SGV KHOA HOC 4

["","","","","","","","","","","Ho\u1ea1t \u0111\u1ed9ng 5: \u0110\u1ed1 em * M\u1ee5c ti\u00eau: HS v\u1eadn d\u1ee5ng \u0111\u01b0\u1ee3c ki\u1ebfn th\u1ee9c v\u1ec1 v\u1eadt cho \u00e1nh s\u00e1ng truy\u1ec1n qua v\u00e0 v\u1eadt c\u1ea3n \u00e1nh s\u00e1ng \u0111\u1ec3 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi li\u00ean quan \u0111\u1ebfn \u0111\u1eddi s\u1ed1ng th\u1ef1c ti\u1ec5n. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV n\u00eau c\u00e2u \u0111\u1ed1 v\u00e0 y\u00eau c\u1ea7u HS tr\u1ea3 l\u1eddi: + R\u00e8m c\u1eeda th\u01b0\u1eddng \u0111\u01b0\u1ee3c d\u00f9ng \u0111\u1ec3 l\u00e0m g\u00ec? + B\u1ec3 nu\u00f4i c\u00e1 c\u1ea3nh th\u01b0\u1eddng \u0111\u01b0\u1ee3c l\u00e0m b\u1eb1ng g\u00ec? V\u00ec sao? \u2013 HS thi \u0111ua tr\u1ea3 l\u1eddi. C\u00e1c HS kh\u00e1c nh\u1eadn x\u00e9t v\u00e0 b\u1ed5 sung. \u2013 GV c\u00f3 th\u1ec3 t\u00ecm v\u00e0 n\u00eau th\u00eam c\u00e1c c\u00e2u \u0111\u1ed1 kh\u00e1c \u0111\u1ec3 HS bi\u1ebft th\u00eam nh\u1eefng \u1ee9ng d\u1ee5ng kh\u00e1c c\u1ee7a v\u1eadt cho \u00e1nh s\u00e1ng truy\u1ec1n qua v\u00e0 v\u1eadt c\u1ea3n \u00e1nh s\u00e1ng trong \u0111\u1eddi s\u1ed1ng th\u1ef1c ti\u1ec5n. G\u1ee3i \u00fd: + R\u00e8m c\u1eeda th\u01b0\u1eddng \u0111\u01b0\u1ee3c l\u00e0m b\u1eb1ng v\u1ea3i. V\u1ea3i l\u00e0 ch\u1ea5t kh\u00f4ng cho \u00e1nh s\u00e1ng truy\u1ec1n qua n\u00ean gi\u00fap che b\u1edbt \u00e1nh s\u00e1ng. + B\u1ec3 nu\u00f4i c\u00e1 c\u1ea3nh th\u01b0\u1eddng \u0111\u01b0\u1ee3c l\u00e0m b\u1eb1ng k\u00ednh trong \u0111\u1ec3 ta c\u00f3 th\u1ec3 quan s\u00e1t \u0111\u01b0\u1ee3c c\u00e1c con c\u00e1 v\u00e0 c\u1ea3nh v\u1eadt b\u00ean trong b\u1ec3. * K\u1ebft lu\u1eadn: Nh\u1eefng v\u1eadt c\u1ea3n \u00e1nh s\u00e1ng ho\u1eb7c cho \u00e1nh s\u00e1ng truy\u1ec1n qua c\u00f3 nhi\u1ec1u \u1ee9ng d\u1ee5ng h\u1eefu \u00edch trong \u0111\u1eddi s\u1ed1ng. Tu\u1ef3 t\u1eebng tr\u01b0\u1eddng h\u1ee3p v\u00e0 nhu c\u1ea7u m\u00e0 con ng\u01b0\u1eddi s\u1eed d\u1ee5ng v\u1eadt cho \u00e1nh s\u00e1ng truy\u1ec1n qua v\u00e0 v\u1eadt c\u1ea3n \u00e1nh s\u00e1ng sao cho h\u1ee3p l\u00ed. * Th\u00f4ng tin d\u00e0nh cho GV: Ngo\u00e0i nh\u1eefng v\u1eadt ho\u1eb7c ch\u1ea5t c\u1ea3n ho\u00e0n to\u00e0n \u00e1nh s\u00e1ng v\u00e0 nh\u1eefng v\u1eadt ho\u1eb7c ch\u1ea5t cho \u00e1nh s\u00e1ng truy\u1ec1n qua (v\u1eadt ho\u1eb7c ch\u1ea5t trong su\u1ed1t), c\u00f2n c\u00f3 nh\u1eefng v\u1eadt ho\u1eb7c ch\u1ea5t trong m\u1edd, t\u1ee9c l\u00e0 ch\u1ec9 cho \u00e1nh s\u00e1ng truy\u1ec1n qua m\u1ed9t ph\u1ea7n, v\u00ed d\u1ee5 nh\u01b0 k\u00ednh m\u1edd, m\u00e0n s\u01b0\u01a1ng,\u2026 \u2013 GV y\u00eau c\u1ea7u HS \u0111\u1ecdc n\u1ed9i dung Em \u0111\u00e3 h\u1ecdc \u0111\u01b0\u1ee3c: \u2022\t Ta nh\u00ecn th\u1ea5y \u0111\u01b0\u1ee3c m\u1ed9t v\u1eadt khi v\u1eadt n\u00e0y ph\u00e1t s\u00e1ng ho\u1eb7c \u0111\u01b0\u1ee3c chi\u1ebfu s\u00e1ng. M\u1eb7t Tr\u1eddi, b\u00f3ng \u0111\u00e8n, ng\u1ecdn l\u1eeda c\u1ee7a n\u1ebfn (\u0111\u00e8n c\u1ea7y),... l\u00e0 c\u00e1c v\u1eadt ph\u00e1t s\u00e1ng. V\u1eadt \u0111\u01b0\u1ee3c chi\u1ebfu s\u00e1ng khi nh\u1eadn \u0111\u01b0\u1ee3c \u00e1nh s\u00e1ng chi\u1ebfu \u0111\u1ebfn. \u2022\t \u00c1nh s\u00e1ng truy\u1ec1n qua \u0111\u01b0\u1ee3c nh\u1eefng ch\u1ea5t trong su\u1ed1t nh\u01b0 thu\u1ef7 tinh, n\u01b0\u1edbc trong, kh\u00f4ng kh\u00ed s\u1ea1ch,... Nh\u1eefng v\u1eadt c\u1ea3n \u00e1nh s\u00e1ng nh\u01b0 b\u1ee9c t\u01b0\u1eddng g\u1ea1ch, mi\u1ebfng g\u1ed7,... kh\u00f4ng cho \u00e1nh s\u00e1ng truy\u1ec1n qua. Ho\u1ea1t \u0111\u1ed9ng ti\u1ebfp n\u1ed1i sau b\u00e0i h\u1ecdc GV y\u00eau c\u1ea7u HS v\u1ec1 nh\u00e0 t\u00ecm th\u00eam c\u00e1c v\u00ed d\u1ee5 v\u1ec1: v\u1eadt ph\u00e1t s\u00e1ng, v\u1eadt \u0111\u01b0\u1ee3c chi\u1ebfu s\u00e1ng, v\u1eadt c\u1ea3n \u00e1nh s\u00e1ng, v\u1eadt cho \u00e1nh s\u00e1ng truy\u1ec1n qua c\u00f3 \u1edf xung quanh em. Ti\u1ebft 2 Ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng * M\u1ee5c ti\u00eau: T\u1ea1o h\u1ee9ng th\u00fa v\u00e0 kh\u01a1i g\u1ee3i nh\u1eefng hi\u1ec3u bi\u1ebft \u0111\u00e3 c\u00f3 c\u1ee7a HS v\u1ec1 s\u1ef1 truy\u1ec1n c\u1ee7a \u00e1nh s\u00e1ng trong kh\u00f4ng kh\u00ed. 60","* C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV \u0111\u1eb7t c\u00e2u h\u1ecfi: \u00c1nh s\u00e1ng truy\u1ec1n \u0111i nh\u01b0 th\u1ebf n\u00e0o trong kh\u00f4ng kh\u00ed (theo \u0111\u01b0\u1eddng th\u1eb3ng, \u0111\u01b0\u1eddng v\u00f2ng hay \u0111\u01b0\u1eddng d\u00edch d\u1eafc)? Ho\u1eb7c GV c\u00f3 th\u1ec3 v\u1ebd h\u00ecnh (ho\u1eb7c chi\u1ebfu h\u00ecnh) \u0111\u1ec3 HS quan s\u00e1t v\u00e0 tr\u1ea3 l\u1eddi c\u00e2u h\u1ecfi: Theo em, \u00e1nh s\u00e1ng truy\u1ec1n \u0111i theo \u0111\u01b0\u1eddng 1, \u0111\u01b0\u1eddng 2 hay \u0111\u01b0\u1eddng 3? 1 2 3 \u2013 HS tr\u1ea3 l\u1eddi c\u00e1 nh\u00e2n. \u2013 GV nh\u1eadn x\u00e9t chung v\u00e0 d\u1eabn d\u1eaft v\u00e0o ti\u1ebft 2 c\u1ee7a b\u00e0i h\u1ecdc. Ho\u1ea1t \u0111\u1ed9ng 1: Th\u1ef1c h\u00e0nh th\u00ed nghi\u1ec7m kh\u00e1m ph\u00e1 s\u1ef1 truy\u1ec1n th\u1eb3ng c\u1ee7a \u00e1nh s\u00e1ng * M\u1ee5c ti\u00eau: HS th\u1ef1c hi\u1ec7n th\u00ed nghi\u1ec7m kh\u00e1m ph\u00e1 s\u1ef1 truy\u1ec1n theo \u0111\u01b0\u1eddng th\u1eb3ng c\u1ee7a \u00e1nh s\u00e1ng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV t\u1ed5 ch\u1ee9c cho HS th\u1ef1c hi\u1ec7n th\u00ed nghi\u1ec7m nh\u01b0 n\u1ed9i dung h\u01b0\u1edbng d\u1eabn trong SGK trang 37. \u2013 GV y\u00eau c\u1ea7u HS quan s\u00e1t th\u00ed nghi\u1ec7m v\u00e0 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: + V\u00ec sao khi ba l\u1ed7 tr\u00f2n th\u1eb3ng h\u00e0ng, ta th\u1ea5y c\u00f3 v\u1ec7t s\u00e1ng tr\u00ean t\u01b0\u1eddng? + V\u00ec sao kh\u00f4ng th\u1ea5y v\u1ec7t s\u00e1ng tr\u00ean t\u01b0\u1eddng khi t\u1ea5m b\u00eca gi\u1eefa b\u1ecb l\u1ec7ch sang m\u1ed9t b\u00ean? + Ch\u00fang ta c\u00f3 th\u1ec3 k\u1ebft lu\u1eadn g\u00ec v\u1ec1 \u0111\u01b0\u1eddng truy\u1ec1n c\u1ee7a \u00e1nh s\u00e1ng? \u2013 HS tr\u1ea3 l\u1eddi v\u00e0 nh\u1eadn x\u00e9t l\u1eabn nhau. G\u1ee3i \u00fd: + Khi ba l\u1ed7 tr\u00f2n th\u1eb3ng h\u00e0ng, ta th\u1ea5y c\u00f3 v\u1ec7t s\u00e1ng tr\u00ean t\u01b0\u1eddng v\u00ec \u00e1nh s\u00e1ng truy\u1ec1n theo \u0111\u01b0\u1eddng th\u1eb3ng. + Khi t\u1ea5m b\u00eca \u1edf gi\u1eefa b\u1ecb l\u1ec7ch sang m\u1ed9t b\u00ean th\u00ec \u00e1nh s\u00e1ng s\u1ebd b\u1ecb c\u1ea3n b\u1edfi t\u1ea5m b\u00eca (kh\u00f4ng th\u1ec3 \u0111i qua l\u1ed7 tr\u00f2n tr\u00ean t\u1ea5m b\u00eca n\u00e0y) n\u00ean ta kh\u00f4ng th\u1ea5y v\u1ec7t s\u00e1ng tr\u00ean t\u01b0\u1eddng. + Ch\u00fang ta c\u00f3 th\u1ec3 k\u1ebft lu\u1eadn l\u00e0 \u00e1nh s\u00e1ng truy\u1ec1n theo \u0111\u01b0\u1eddng th\u1eb3ng. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 d\u1eabn d\u1eaft \u0111\u1ec3 HS r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: \u00c1nh s\u00e1ng truy\u1ec1n trong kh\u00f4ng kh\u00ed theo \u0111\u01b0\u1eddng th\u1eb3ng. Ho\u1ea1t \u0111\u1ed9ng 2: T\u00ecm hi\u1ec3u s\u1ef1 t\u1ea1o th\u00e0nh b\u00f3ng c\u1ee7a v\u1eadt, h\u00ecnh d\u1ea1ng v\u00e0 k\u00edch th\u01b0\u1edbc c\u1ee7a b\u00f3ng * M\u1ee5c ti\u00eau: HS th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c th\u00ed nghi\u1ec7m \u0111\u1ec3 t\u00ecm hi\u1ec3u nguy\u00ean nh\u00e2n t\u1ea1o ra b\u00f3ng c\u1ee7a v\u1eadt v\u00e0 s\u1ef1 thay \u0111\u1ed5i k\u00edch th\u01b0\u1edbc, h\u00ecnh d\u1ea1ng c\u1ee7a b\u00f3ng khi v\u1ecb tr\u00ed c\u1ee7a v\u1eadt ho\u1eb7c c\u1ee7a ngu\u1ed3n s\u00e1ng thay \u0111\u1ed5i. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV t\u1ed5 ch\u1ee9c cho HS th\u1ef1c hi\u1ec7n th\u00ed nghi\u1ec7m theo n\u1ed9i dung m\u00f4 t\u1ea3 \u1edf h\u00ecnh 7 (SGK, trang 38). 61","\u2013 HS th\u1ef1c h\u00e0nh, quan s\u00e1t th\u00ed nghi\u1ec7m \u0111\u1ec3 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: + Em nh\u00ecn th\u1ea5y g\u00ec tr\u00ean t\u1ea5m b\u00eca khi co\u0301 h\u00f4\u0323p bu\u0301t gi\u01b0\u0303a t\u00e2\u0301m bi\u0300a v\u00e0 \u0111\u00e8n pin? Vi\u0300 sao? + Hi\u0300nh da\u0323ng va\u0300 ki\u0301ch th\u01b0\u01a1\u0301c b\u00f3ng c\u1ee7a h\u1ed9p b\u00fat tr\u00ean t\u1ea5m b\u00eca thay \u0111\u00f4\u0309i nh\u01b0 th\u00ea\u0301 na\u0300o khi di chuy\u1ec3n \u0111\u00e8n pin ho\u1eb7c h\u1ed9p b\u00fat ra xa v\u00e0 l\u1ea1i g\u1ea7n t\u1ea5m b\u00eca? + Em r\u00fat ra \u0111\u01b0\u1ee3c k\u1ebft lu\u1eadn g\u00ec v\u1ec1 s\u1ef1 thay \u0111\u1ed5i c\u1ee7a b\u00f3ng khi v\u1ecb tr\u00ed c\u1ee7a v\u1eadt ho\u1eb7c ngu\u1ed3n s\u00e1ng thay \u0111\u1ed5i? G\u1ee3i \u00fd: + Em nh\u00ecn th\u1ea5y b\u00f3ng c\u1ee7a h\u1ed9p b\u00fat tr\u00ean t\u1ea5m b\u00eca. V\u00ec h\u1ed9p b\u00fat c\u1ea3n \u00e1nh s\u00e1ng n\u00ean t\u1ea1o th\u00e0nh b\u00f3ng \u0111en tr\u00ean t\u1ea5m b\u00eca. + Khi di chuy\u1ec3n \u0111\u00e8n pin ho\u1eb7c h\u1ed9p b\u00fat l\u1ea1i g\u1ea7n t\u1ea5m b\u00eca: b\u00f3ng l\u1edbn h\u01a1n; Khi di chuy\u1ec3n \u0111\u00e8n pin ho\u1eb7c h\u1ed9p b\u00fat ra xa t\u1ea5m b\u00eca: b\u00f3ng nh\u1ecf h\u01a1n. \u2013 HS tr\u1ea3 l\u1eddi c\u00e2u h\u1ecfi v\u00e0 nh\u1eadn x\u00e9t l\u1eabn nhau. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 h\u01b0\u1edbng d\u1eabn HS r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: \u00c1nh s\u00e1ng chi\u1ebfu v\u00e0o m\u1ed9t v\u1eadt c\u1ea3n \u00e1nh s\u00e1ng s\u1ebd t\u1ea1o b\u00f3ng \u1edf ph\u00eda sau v\u1eadt \u0111\u00f3. B\u00f3ng c\u1ee7a v\u1eadt c\u1ea3n \u00e1nh s\u00e1ng c\u00f3 h\u00ecnh d\u1ea1ng t\u01b0\u01a1ng t\u1ef1 v\u1edbi v\u1eadt v\u00e0 c\u00f3 th\u1ec3 l\u1edbn ho\u1eb7c nh\u1ecf h\u01a1n v\u1eadt. K\u00edch th\u01b0\u1edbc b\u00f3ng c\u1ee7a v\u1eadt thay \u0111\u1ed5i khi v\u1ecb tr\u00ed c\u1ee7a v\u1eadt ho\u1eb7c c\u1ee7a ngu\u1ed3n s\u00e1ng thay \u0111\u1ed5i. Ho\u1ea1t \u0111\u1ed9ng 3: \u0110\u1ed1 em * M\u1ee5c ti\u00eau: HS v\u1eadn d\u1ee5ng ki\u1ebfn th\u1ee9c v\u1ec1 b\u00f3ng c\u1ee7a v\u1eadt \u0111\u1ec3 gi\u1ea3i th\u00edch \u0111\u01b0\u1ee3c hi\u1ec7n t\u01b0\u1ee3ng trong th\u1ef1c ti\u1ec5n \u0111\u1eddi s\u1ed1ng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS quan s\u00e1t h\u00ecnh 8a v\u00e0 8b (SGK, trang 38) v\u00e0 th\u1ea3o lu\u1eadn nh\u00f3m \u0111\u00f4i \u0111\u1ec3 th\u1ef1c hi\u1ec7n nhi\u1ec7m v\u1ee5: X\u00e1c \u0111\u1ecbnh h\u01b0\u1edbng chi\u1ebfu c\u1ee7a M\u1eb7t Tr\u1eddi \u0111\u1ebfn c\u00e2y trong h\u00ecnh 8a v\u00e0 8b. \u2013 GV h\u1ecfi HS: \u0110\u1ec3 tr\u00e1nh n\u1eafng, em s\u1ebd ch\u1ecdn \u0111\u1ee9ng \u1edf v\u1ecb tr\u00ed n\u00e0o? \u2013 HS th\u1ef1c hi\u1ec7n nhi\u1ec7m v\u1ee5 v\u00e0 tr\u1ea3 l\u1eddi c\u00e2u h\u1ecfi. G\u1ee3i \u00fd: Th\u00e2n c\u00e2y l\u00e0 v\u1eadt c\u1ea3n \u00e1nh s\u00e1ng n\u00ean \u00e1nh s\u00e1ng t\u1eeb M\u1eb7t Tr\u1eddi chi\u1ebfu xu\u1ed1ng \u0111\u1ebfn c\u00e2y s\u1ebd t\u1ea1o b\u00f3ng c\u1ee7a c\u00e2y tr\u00ean m\u1eb7t \u0111\u1ea5t. H\u00ecnh 8a: M\u1eb7t Tr\u1eddi \u1edf ph\u00eda sau th\u00e2n c\u00e2y. H\u00ecnh 8b: M\u1eb7t Tr\u1eddi \u1edf ph\u00eda tr\u00ean th\u00e2n c\u00e2y. \u0110\u1ec3 tr\u00e1nh n\u1eafng, em s\u1ebd ch\u1ecdn \u0111\u1ee9ng \u1edf trong v\u00f9ng b\u00f3ng c\u1ee7a c\u00e2y. Ho\u1ea1t \u0111\u1ed9ng 4: Tr\u00f2 ch\u01a1i \u201cT\u1ea1o b\u00f3ng b\u1eb1ng tay\u201d * M\u1ee5c ti\u00eau: HS v\u1eadn d\u1ee5ng ki\u1ebfn th\u1ee9c v\u1ec1 s\u1ef1 t\u1ea1o b\u00f3ng c\u1ee7a v\u1eadt \u0111\u1ec3 t\u1ea1o h\u00ecnh c\u00e1c con v\u1eadt theo kh\u1ea3 n\u0103ng c\u1ee7a b\u1ea3n th\u00e2n. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV t\u1ed5 ch\u1ee9c cho HS th\u1ef1c hi\u1ec7n tr\u00f2 ch\u01a1i: D\u00f9ng hai b\u00e0n tay t\u1ea1o b\u00f3ng tr\u00ean t\u01b0\u1eddng nh\u01b0 trong c\u00e1c h\u00ecnh 9a, 9b, 9c (SGK, trang 38) v\u00e0 \u0111o\u00e1n \u0111\u00f3 l\u00e0 con v\u1eadt g\u00ec. \u2013 HS th\u1ef1c hi\u1ec7n tr\u00f2 ch\u01a1i. \u2013 GV h\u1ecfi HS: V\u00ec sao c\u00f3 b\u00f3ng gi\u1ed1ng h\u00ecnh d\u1ea1ng c\u00e1c con v\u1eadt tr\u00ean t\u01b0\u1eddng? \u2013 HS tr\u1ea3 l\u1eddi. GV nh\u1eadn x\u00e9t v\u00e0 k\u1ebft lu\u1eadn. 62","* K\u1ebft lu\u1eadn: B\u00f3ng c\u1ee7a v\u1eadt c\u00f3 h\u00ecnh d\u1ea1ng t\u01b0\u01a1ng t\u1ef1 v\u1eadt. \u2013 GV y\u00eau c\u1ea7u HS \u0111\u1ecdc n\u1ed9i dung Em \u0111\u00e3 h\u1ecdc \u0111\u01b0\u1ee3c: \u2022\t Trong kh\u00f4ng kh\u00ed, \u00e1nh s\u00e1ng truy\u1ec1n theo \u0111\u01b0\u1eddng th\u1eb3ng. \u2022\t \u00c1nh s\u00e1ng chi\u1ebfu v\u00e0o m\u1ed9t v\u1eadt c\u1ea3n \u00e1nh s\u00e1ng s\u1ebd t\u1ea1o b\u00f3ng \u1edf ph\u00eda sau v\u1eadt \u0111\u00f3. \u2022\t B\u00f3ng c\u1ee7a v\u1eadt c\u1ea3n \u00e1nh s\u00e1ng c\u00f3 h\u00ecnh d\u1ea1ng t\u01b0\u01a1ng t\u1ef1 v\u1edbi v\u1eadt v\u00e0 c\u00f3 th\u1ec3 l\u1edbn ho\u1eb7c nh\u1ecf h\u01a1n v\u1eadt. K\u00edch th\u01b0\u1edbc b\u00f3ng c\u1ee7a v\u1eadt thay \u0111\u1ed5i khi v\u1ecb tr\u00ed c\u1ee7a v\u1eadt ho\u1eb7c c\u1ee7a ngu\u1ed3n s\u00e1ng thay \u0111\u1ed5i. \u2013 GV d\u1eabn d\u1eaft \u0111\u1ec3 HS n\u00eau \u0111\u01b0\u1ee3c c\u00e1c t\u1eeb kho\u00e1 c\u1ee7a b\u00e0i: V\u1eadt ph\u00e1t s\u00e1ng \u2013 V\u1eadt \u0111\u01b0\u1ee3c chi\u1ebfu s\u00e1ng \u2013 V\u1eadt c\u1ea3n \u00e1nh s\u00e1ng \u2013 Truy\u1ec1n th\u1eb3ng \u2013 B\u00f3ng c\u1ee7a v\u1eadt \u2013 Ngu\u1ed3n s\u00e1ng. Ho\u1ea1t \u0111\u1ed9ng ti\u1ebfp n\u1ed1i sau b\u00e0i h\u1ecdc GV y\u00eau c\u1ea7u HS v\u1ec1 nh\u00e0 t\u00ecm hi\u1ec3u vai tr\u00f2 c\u1ee7a \u00e1nh s\u00e1ng \u0111\u1ed1i v\u1edbi s\u1ef1 s\u1ed1ng \u0111\u1ec3 chu\u1ea9n b\u1ecb cho ti\u1ebft h\u1ecdc sau. B\u00e0i 9. \u00c1NH S\u00c1NG V\u1edaI \u0110\u1edcI S\u1ed0NG (2 ti\u1ebft) I. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t Sau b\u00e0i h\u1ecdc, HS: \u2013 N\u00eau \u0111\u01b0\u1ee3c vai tr\u00f2 c\u1ee7a \u00e1nh s\u00e1ng \u0111\u1ed1i v\u1edbi s\u1ef1 s\u1ed1ng; li\u00ean h\u1ec7 \u0111\u01b0\u1ee3c c\u00e1c t\u00ednh ch\u1ea5t c\u1ee7a \u00e1nh s\u00e1ng v\u1edbi th\u1ef1c t\u1ebf. \u2013 Bi\u1ebft tr\u00e1nh \u00e1nh s\u00e1ng qu\u00e1 m\u1ea1nh chi\u1ebfu v\u00e0o m\u1eaft; kh\u00f4ng \u0111\u1ecdc, vi\u1ebft d\u01b0\u1edbi \u00e1nh s\u00e1ng qu\u00e1 y\u1ebfu; th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c t\u01b0 th\u1ebf ng\u1ed3i h\u1ecdc, gi\u1eef kho\u1ea3ng c\u00e1ch \u0111\u1ecdc, vi\u1ebft ph\u00f9 h\u1ee3p \u0111\u1ec3 b\u1ea3o v\u1ec7 m\u1eaft, tr\u00e1nh b\u1ecb c\u1eadn th\u1ecb. II. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc \u2013 GV: C\u00e1c h\u00ecnh trong b\u00e0i 9 SGK. \u2013 HS: SGK, VBT. III. C\u00c1C Ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc Ti\u1ebft 1 Ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng * M\u1ee5c ti\u00eau: T\u1ea1o h\u1ee9ng th\u00fa v\u00e0 kh\u01a1i g\u1ee3i nh\u1eefng hi\u1ec3u bi\u1ebft \u0111\u00e3 c\u00f3 c\u1ee7a HS v\u1ec1 vai tr\u00f2 c\u1ee7a \u00e1nh s\u00e1ng trong \u0111\u1eddi s\u1ed1ng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV \u0111\u1eb7t c\u00e2u h\u1ecfi: \u0110i\u1ec1u g\u00ec s\u1ebd x\u1ea3y ra \u0111\u1ed1i v\u1edbi sinh v\u1eadt tr\u00ean Tr\u00e1i \u0110\u1ea5t n\u1ebfu kh\u00f4ng c\u00f3 \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi? \u2013 GV m\u1eddi 1 \u2013 2 HS tr\u1ea3 l\u1eddi. \u2013 GV nh\u1eadn x\u00e9t chung v\u00e0 d\u1eabn d\u1eaft v\u00e0o b\u00e0i h\u1ecdc: \u201c\u00c1nh s\u00e1ng v\u1edbi \u0111\u1eddi s\u1ed1ng\u201d. 63","Ho\u1ea1t \u0111\u1ed9ng 1: T\u00ecm hi\u1ec3u vai tr\u00f2 c\u1ee7a \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi \u0111\u1ed1i v\u1edbi s\u1ef1 s\u1ed1ng c\u1ee7a con ng\u01b0\u1eddi, \u0111\u1ed9ng v\u1eadt v\u00e0 th\u1ef1c v\u1eadt * M\u1ee5c ti\u00eau: HS n\u00eau \u0111\u01b0\u1ee3c vai tr\u00f2 c\u1ee7a \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi \u0111\u1ed1i v\u1edbi con ng\u01b0\u1eddi, \u0111\u1ed9ng v\u1eadt v\u00e0 th\u1ef1c v\u1eadt. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chia HS th\u00e0nh c\u00e1c nh\u00f3m 4, y\u00eau c\u1ea7u m\u1ed7i nh\u00f3m quan s\u00e1t c\u00e1c h\u00ecnh t\u1eeb 1 \u0111\u1ebfn 4 (SGK, trang 39), th\u1ea3o lu\u1eadn v\u00e0 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: + \u1ede h\u00ecnh 1, tr\u1ebb em sinh ho\u1ea1t nh\u01b0 th\u1ebf n\u00e0o khi \u0111\u01b0\u1ee3c \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi s\u01b0\u1edfi \u1ea5m? + C\u00e2y tr\u1ed3ng trong h\u00ecnh 2 m\u1ecdc nghi\u00eang v\u1ec1 h\u01b0\u1edbng n\u00e0o? V\u00ec sao? + Lo\u00e0i v\u1eadt c\u00f3 th\u1ec3 sinh ho\u1ea1t, t\u00ecm th\u1ee9c \u0103n trong b\u00f3ng t\u1ed1i \u0111\u01b0\u1ee3c kh\u00f4ng? + Lo\u00e0i v\u1eadt c\u00f3 c\u1ea7n s\u01b0\u1edfi \u1ea5m kh\u00f4ng? + \u00c1nh s\u00e1ng m\u1eb7t tr\u1eddi c\u00f3 vai tr\u00f2 nh\u01b0 th\u00ea\u0301 na\u0300o \u0111\u1ed1i v\u1edbi s\u1ef1 s\u1ed1ng c\u1ee7a con ng\u01b0\u1eddi, \u0111\u1ed9ng v\u1eadt v\u00e0 th\u1ef1c v\u1eadt? \u2013 GV cho HS ti\u1ebfp t\u1ee5c quan s\u00e1t c\u00e1c h\u00ecnh 5 v\u00e0 6 (SGK, trang 40), th\u1ea3o lu\u1eadn v\u00e0 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: + V\u00ec sao tr\u1ea1i gia c\u1ea7m \u0111\u01b0\u1ee3c chi\u1ebfu s\u00e1ng nh\u01b0 \u1edf h\u00ecnh 5? + Ng\u01b0\u1eddi ta th\u1eafp \u0111\u00e8n trong v\u01b0\u1eddn c\u00e2y nh\u01b0 \u1edf h\u00ecnh 6 \u0111\u1ec3 l\u00e0m g\u00ec? + \u00c1nh s\u00e1ng nh\u00e2n t\u1ea1o \u0111em l\u1ea1i l\u1ee3i \u00edch g\u00ec trong vi\u1ec7c ch\u0103n nu\u00f4i v\u00e0 tr\u1ed3ng tr\u1ecdt? \u2013 GV y\u00eau c\u1ea7u HS xem l\u1ea1i s\u01a1 \u0111\u1ed3 v\u00f2ng tu\u1ea7n ho\u00e0n n\u01b0\u1edbc trong t\u1ef1 nhi\u00ean (SGK, trang 12) \u0111\u1ec3 tr\u1ea3 l\u1eddi c\u00e2u h\u1ecfi: \u00c1nh s\u00e1ng m\u1eb7t tr\u1eddi \u0111\u00f3ng vai tr\u00f2 quan tr\u1ecdng \u1edf giai \u0111o\u1ea1n n\u00e0o trong v\u00f2ng tu\u1ea7n ho\u00e0n c\u1ee7a n\u01b0\u1edbc trong t\u1ef1 nhi\u00ean? \u2013 GV \u0111\u1ec1 ngh\u1ecb HS: K\u1ec3 c\u00e1c v\u00ed d\u1ee5 kh\u00e1c th\u1ec3 hi\u1ec7n vai tr\u00f2 c\u1ee7a \u00e1nh s\u00e1ng trong \u0111\u1eddi s\u1ed1ng. \u2013 HS tr\u1ea3 l\u1eddi, GV nh\u1eadn x\u00e9t v\u00e0 ch\u1ed1t l\u1ea1i: \u00c1nh s\u00e1ng m\u1eb7t tr\u1eddi c\u00f3 t\u00e1c d\u1ee5ng s\u01b0\u1edfi \u1ea5m, chi\u1ebfu s\u00e1ng, \u0111\u00f3ng vai tr\u00f2 quan tr\u1ecdng trong v\u00f2ng tu\u1ea7n ho\u00e0n c\u1ee7a n\u01b0\u1edbc trong t\u1ef1 nhi\u00ean. \u00c1nh s\u00e1ng nh\u00e2n t\u1ea1o c\u0169ng c\u00f3 vai tr\u00f2 th\u00fac \u0111\u1ea9y s\u1ef1 sinh s\u1ea3n \u1edf \u0111\u1ed9ng v\u1eadt v\u00e0 s\u1ef1 ph\u00e1t tri\u1ec3n \u1edf th\u1ef1c v\u1eadt. \u2013 GV d\u1eabn d\u1eaft HS c\u00f9ng r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: \u00c1nh s\u00e1ng \u0111\u00f3ng vai tr\u00f2 quan tr\u1ecdng trong s\u1ef1 s\u1ed1ng c\u1ee7a con ng\u01b0\u1eddi, \u0111\u1ed9ng v\u1eadt v\u00e0 th\u1ef1c v\u1eadt. M\u1ecdi ho\u1ea1t \u0111\u1ed9ng c\u1ee7a con ng\u01b0\u1eddi, \u0111\u1ed9ng v\u1eadt v\u00e0 th\u1ef1c v\u1eadt \u0111\u1ec1u c\u1ea7n \u0111\u1ebfn \u00e1nh s\u00e1ng. Ho\u1ea1t \u0111\u1ed9ng 2: C\u00f9ng th\u1ea3o lu\u1eadn * M\u1ee5c ti\u00eau: HS nh\u1eadn th\u1ee9c \u0111\u01b0\u1ee3c t\u1ea7m quan tr\u1ecdng c\u1ee7a \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi \u0111\u1ed1i v\u1edbi \u0111\u1eddi s\u1ed1ng c\u1ee7a con ng\u01b0\u1eddi v\u00e0 s\u1ef1 sinh tr\u01b0\u1edfng, ph\u00e1t tri\u1ec3n c\u1ee7a \u0111\u1ed9ng v\u1eadt v\u00e0 th\u1ef1c v\u1eadt. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 4, y\u00eau c\u1ea7u m\u1ed7i nh\u00f3m th\u1ea3o lu\u1eadn v\u00e0 tr\u1ea3 l\u1eddi c\u00e2u h\u1ecfi: \u0110\u1eddi s\u1ed1ng c\u1ee7a con ng\u01b0\u1eddi v\u00e0 \u0111\u1ed9ng v\u1eadt, th\u1ef1c v\u1eadt s\u1ebd b\u1ecb \u1ea3nh h\u01b0\u1edfng nh\u01b0 th\u1ebf n\u00e0o khi thi\u1ebfu \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi? V\u00ec sao? \u2013 GV m\u1eddi \u0111\u1ea1i di\u1ec7n c\u00e1c nh\u00f3m tr\u1ea3 l\u1eddi. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: \u00c1nh s\u00e1ng m\u1eb7t tr\u1eddi c\u1ea7n cho s\u1ef1 s\u1ed1ng c\u1ee7a con ng\u01b0\u1eddi, \u0111\u1ed9ng v\u1eadt v\u00e0 th\u1ef1c v\u1eadt. 64","Ho\u1ea1t \u0111\u1ed9ng 3: S\u1eed d\u1ee5ng \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi trong \u0111\u1eddi s\u1ed1ng * M\u1ee5c ti\u00eau: HS nh\u1eadn th\u1ee9c \u0111\u01b0\u1ee3c \u00edch l\u1ee3i c\u1ee7a vi\u1ec7c sinh ho\u1ea1t d\u01b0\u1edbi \u00e1nh n\u1eafng m\u1eb7t tr\u1eddi v\u00e0 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c th\u1eddi gian th\u00edch h\u1ee3p nh\u1ea5t trong ng\u00e0y \u0111\u1ec3 ra ngo\u00e0i tr\u1eddi n\u1eafng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS quan s\u00e1t v\u00e0 \u0111\u1ecdc th\u00f4ng tin trong h\u00ecnh 7 (SGK, trang 40), th\u1ea3o lu\u1eadn nh\u00f3m \u0111\u00f4i \u0111\u1ec3 tr\u1ea3 l\u1eddi c\u00e2u h\u1ecfi: Em \u0111\u00f4\u0300ng ti\u0300nh v\u01a1\u0301i y\u0301 ki\u00ea\u0301n cu\u0309a ba\u0323n na\u0300o? V\u00ec sao? \u2013 GV c\u00f3 th\u1ec3 t\u1ed5 ch\u1ee9c cho HS \u0111\u00f3ng vai \u0111\u1ec3 th\u1ec3 hi\u1ec7n n\u1ed9i dung t\u00ecnh hu\u1ed1ng. \u2013 HS tr\u1ea3 l\u1eddi. GV nh\u1eadn x\u00e9t v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: \u00c1nh s\u00e1ng m\u1eb7t tr\u1eddi r\u1ea5t c\u1ea7n thi\u1ebft v\u00e0 t\u1ed1t cho s\u1ee9c khoe\u0309 ch\u00fang ta. Ch\u00fang ta c\u1ea7n th\u01b0\u1eddng xuy\u00ean ra ngo\u00e0i n\u1eafng v\u00e0o nh\u1eefng kho\u1ea3ng th\u1eddi gian th\u00edch h\u1ee3p nh\u1ea5t trong ng\u00e0y. \u2013 GV y\u00eau c\u1ea7u HS \u0111\u1ecdc n\u1ed9i dung m\u1ee5c Em \u0111\u00e3 h\u1ecdc \u0111\u01b0\u1ee3c: \u00c1nh s\u00e1ng \u0111\u00f3ng vai tr\u00f2 quan tr\u1ecdng trong s\u1ef1 s\u1ed1ng c\u1ee7a con ng\u01b0\u1eddi, \u0111\u1ed9ng v\u1eadt v\u00e0 th\u1ef1c v\u1eadt. M\u1ecdi ho\u1ea1t \u0111\u1ed9ng c\u1ee7a con ng\u01b0\u1eddi, \u0111\u1ed9ng v\u1eadt v\u00e0 th\u1ef1c v\u1eadt \u0111\u1ec1u c\u1ea7n \u0111\u1ebfn \u00e1nh s\u00e1ng. * Th\u00f4ng tin d\u00e0nh cho GV: Ng\u00f4i sao l\u00e0 m\u1ed9t kh\u1ed1i kh\u00ed kh\u1ed5ng l\u1ed3, c\u00f3 th\u1ec3 t\u1ef1 ph\u00e1t s\u00e1ng trong v\u0169 tr\u1ee5. Nhi\u1ec1u ng\u00f4i sao t\u1eadp h\u1ee3p th\u00e0nh t\u1eebng nh\u00f3m, g\u1ecdi l\u00e0 thi\u00ean h\u00e0. H\u1ec7 M\u1eb7t Tr\u1eddi n\u1eb1m trong thi\u00ean h\u00e0 c\u00f3 t\u00ean l\u00e0 Ng\u00e2n h\u00e0, ch\u1ee9a h\u00e0ng tr\u0103m t\u1ec9 ng\u00f4i sao. M\u1eb7t Tr\u1eddi l\u00e0 ng\u00f4i sao g\u1ea7n Tr\u00e1i \u0110\u1ea5t nh\u1ea5t, l\u00e0 ngu\u1ed3n n\u0103ng l\u01b0\u1ee3ng h\u1ea7u nh\u01b0 v\u00f4 t\u1eadn, cung c\u1ea5p \u00e1nh s\u00e1ng v\u00e0 nhi\u1ec7t cho Tr\u00e1i \u0110\u1ea5t, nh\u1edd \u0111\u00f3, s\u1ef1 s\u1ed1ng tr\u00ean Tr\u00e1i \u0110\u1ea5t c\u00f3 th\u1ec3 t\u1ed3n t\u1ea1i. \u00c1nh s\u00e1ng m\u1eb7t tr\u1eddi truy\u1ec1n \u0111i v\u1edbi t\u1ed1c \u0111\u1ed9 r\u1ea5t l\u1edbn, kho\u1ea3ng 300 000 km\/s. Do kho\u1ea3ng c\u00e1ch t\u1eeb M\u1eb7t Tr\u1eddi \u0111\u1ebfn Tr\u00e1i \u0110\u1ea5t r\u1ea5t l\u1edbn n\u00ean \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi truy\u1ec1n t\u1eeb M\u1eb7t Tr\u1eddi \u0111\u1ebfn Tr\u00e1i \u0110\u1ea5t m\u1ea5t th\u1eddi gian kho\u1ea3ng 8 ph\u00fat 20 gi\u00e2y. \t\t\t\t(Ngu\u1ed3n: https:\/\/kids.britannica.com\/kids\/article\/star\/353808 \t\t\t\t\t https:\/\/kids.nationalgeographic.com\/space\/article\/sun) Ho\u1ea1t \u0111\u1ed9ng ti\u1ebfp n\u1ed1i sau b\u00e0i h\u1ecdc GV y\u00eau c\u1ea7u HS v\u1ec1 nh\u00e0 t\u00ecm hi\u1ec3u v\u1ec1 nh\u1eefng d\u1ea1ng \u00e1nh s\u00e1ng c\u00f3 th\u1ec3 g\u00e2y h\u1ea1i cho m\u1eaft \u0111\u1ec3 chu\u1ea9n b\u1ecb cho ti\u1ebft h\u1ecdc sau. Ti\u1ebft 2 Ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng * M\u1ee5c ti\u00eau: T\u1ea1o h\u1ee9ng th\u00fa v\u00e0 kh\u01a1i g\u1ee3i nh\u1eefng hi\u1ec3u bi\u1ebft \u0111\u00e3 c\u00f3 c\u1ee7a HS v\u1ec1 c\u00e1ch b\u1ea3o v\u1ec7 m\u1eaft. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS: K\u1ec3 nh\u1eefng tr\u01b0\u1eddng h\u1ee3p \u00e1nh s\u00e1ng l\u00e0m h\u1ea1i m\u1eaft m\u00e0 em bi\u1ebft. \u2013 GV m\u1eddi 1 \u2013 2 HS tr\u1ea3 l\u1eddi. \u2013 GV nh\u1eadn x\u00e9t chung v\u00e0 d\u1eabn d\u1eaft v\u00e0o ti\u1ebft 2 c\u1ee7a b\u00e0i h\u1ecdc. 65","Ho\u1ea1t \u0111\u1ed9ng 1: T\u00ecm hi\u1ec3u nh\u1eefng tr\u01b0\u1eddng h\u1ee3p \u00e1nh s\u00e1ng c\u00f3 th\u1ec3 g\u00e2y h\u1ea1i cho m\u1eaft * M\u1ee5c ti\u00eau: HS nh\u1eadn bi\u1ebft \u0111\u01b0\u1ee3c nh\u1eefng d\u1ea1ng \u00e1nh s\u00e1ng g\u00e2y h\u1ea1i cho m\u1eaft v\u00e0 c\u00e1ch ph\u00f2ng tr\u00e1nh; bi\u1ebft \u0111\u01b0\u1ee3c c\u1ea7n ph\u1ea3i \u0111\u1ecdc s\u00e1ch trong \u0111i\u1ec1u ki\u1ec7n \u00e1nh s\u00e1ng th\u00edch h\u1ee3p \u0111\u1ec3 b\u1ea3o v\u1ec7 m\u1eaft. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV t\u1ed5 ch\u1ee9c cho HS ch\u01a1i tr\u00f2 ch\u01a1i \u201cN\u00ean \u2013 Kh\u00f4ng n\u00ean\u201d. \u2013 GV ph\u1ed5 bi\u1ebfn lu\u1eadt ch\u01a1i: GV chia l\u1edbp th\u00e0nh 2 \u0111\u1ed9i, ph\u00e1t cho m\u1ed7i \u0111\u1ed9i c\u00e1c th\u1ebb h\u00ecnh (GV in c\u00e1c h\u00ecnh \u1edf trang 41 SGK). Trong th\u1eddi gian 1 ph\u00fat, m\u1ed7i \u0111\u1ed9i l\u1ea7n l\u01b0\u1ee3t l\u00ean \u0111\u00ednh c\u00e1c h\u00ecnh v\u00e0o c\u1ed9t \u201cN\u00ean l\u00e0m\u201d ho\u1eb7c \u201cKh\u00f4ng n\u00ean l\u00e0m\u201d tr\u00ean b\u1ea3ng. \u0110\u1ed9i n\u00e0o ho\u00e0n th\u00e0nh nhanh nh\u1ea5t v\u00e0 \u0111\u00fang s\u1ebd gi\u00e0nh chi\u1ebfn th\u1eafng (ho\u1eb7c GV c\u00f3 th\u1ec3 chi\u1ebfu c\u00e1c h\u00ecnh t\u1eeb 8 \u0111\u1ebfn 13 \u1edf trang 41 SGK cho HS quan s\u00e1t. HS m\u1ed7i nh\u00f3m s\u1ebd \u0111i\u1ec1n s\u1ed1 th\u1ee9 t\u1ef1 c\u1ee7a m\u1ed7i h\u00ecnh v\u00e0o c\u1ed9t \u201cN\u00ean l\u00e0m\u201d ho\u1eb7c \u201cKh\u00f4ng n\u00ean l\u00e0m\u201d). \u2013 GV m\u1eddi \u0111\u1ea1i di\u1ec7n c\u00e1c nh\u00f3m l\u00ean chia s\u1ebb v\u00e0 gi\u1ea3i th\u00edch k\u1ebft qu\u1ea3 c\u1ee7a nh\u00f3m m\u00ecnh. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: Ta n\u00ean tr\u00e1nh nh\u00ecn tr\u1ef1c ti\u1ebfp v\u00e0o \u00e1nh n\u1eafng m\u1eb7t tr\u1eddi, tia l\u1eeda h\u00e0n v\u00ec nh\u1eefng \u00e1nh s\u00e1ng n\u00e0y c\u00f3 th\u1ec3 g\u00e2y h\u1ea1i cho m\u1eaft. Ch\u00fang ta c\u1ea7n \u0111\u1ecdc s\u00e1ch, xem m\u00e0n h\u00ecnh thi\u1ebft b\u1ecb \u0111i\u1ec7n t\u1eed \u1edf n\u01a1i c\u00f3 \u00e1nh s\u00e1ng th\u00edch h\u1ee3p \u0111\u1ec3 tr\u00e1nh g\u00e2y h\u1ea1i cho m\u1eaft. \u2013 GV \u0111\u1eb7t c\u00e2u h\u1ecfi \u0111\u1ec3 m\u1edf r\u1ed9ng th\u00eam ki\u1ebfn th\u1ee9c cho HS: + C\u00e1c em c\u00f3 bao gi\u1edd th\u1ea5y ho\u1eb7c s\u1eed d\u1ee5ng b\u00fat la-de ch\u01b0a? Tia s\u00e1ng ph\u00e1t ra t\u1eeb b\u00fat n\u00e0y c\u00f3 \u0111\u1ed9 s\u00e1ng nh\u01b0 th\u1ebf n\u00e0o? + Tia s\u00e1ng la-de c\u00f3 th\u1ec3 g\u00e2y h\u1ea1i cho m\u1eaft kh\u00f4ng? V\u00ec sao? + C\u1ea7n l\u00e0m g\u00ec \u0111\u1ec3 tr\u00e1nh t\u00e1c h\u1ea1i c\u1ee7a tia s\u00e1ng la-de cho b\u1ea3n th\u00e2n v\u00e0 cho m\u1ecdi ng\u01b0\u1eddi xung quanh? \u2013 GV m\u1eddi HS tr\u1ea3 l\u1eddi theo kh\u1ea3 n\u0103ng hi\u1ec3u bi\u1ebft c\u1ee7a b\u1ea3n th\u00e2n. \u2013 GV ch\u1ed1t l\u1ea1i: B\u00fat la-de l\u00e0 m\u1ed9t ngu\u1ed3n s\u00e1ng r\u1ea5t m\u1ea1nh, c\u00f3 th\u1ec3 l\u00e0m t\u1ed5n th\u01b0\u01a1ng m\u1eaft. Ch\u00fang ta c\u1ea7n tr\u00e1nh \u00e1nh s\u00e1ng la-de chi\u1ebfu th\u1eb3ng v\u00e0o m\u1eaft; tuy\u1ec7t \u0111\u1ed1i kh\u00f4ng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng b\u00fat la-de \u0111\u1ec3 chi\u1ebfu v\u00e0o ng\u01b0\u1eddi kh\u00e1c. * Th\u00f4ng tin d\u00e0nh cho GV: T\u00e1c h\u1ea1i c\u00f3 th\u1ec3 c\u00f3 c\u1ee7a tia la-de: \u2022\t Tia la-de v\u1edbi c\u01b0\u1eddng \u0111\u1ed9 th\u1ea5p c\u0169ng c\u00f3 th\u1ec3 g\u00e2y nguy hi\u1ec3m cho m\u1eaft ng\u01b0\u1eddi. Tia la-de c\u00f3 t\u00ednh \u0111\u1ecbnh h\u01b0\u1edbng cao n\u00ean c\u00f3 th\u1ec3 t\u1eadp trung v\u00e0o m\u1ed9t \u0111i\u1ec3m c\u1ef1c nh\u1ecf tr\u00ean v\u00f5ng m\u1ea1c. K\u1ebft qu\u1ea3 l\u00e0 g\u00e2y ra m\u1ed9t v\u1ebft ch\u00e1y t\u1eadp trung, ph\u00e1 hu\u1ef7 c\u00e1c t\u1ebf b\u00e0o m\u1eaft v\u0129nh vi\u1ec5n trong v\u00e0i gi\u00e2y, th\u1eadm ch\u00ed c\u00f3 th\u1ec3 nhanh h\u01a1n. \u2022\t \u0110\u1ed9 an to\u00e0n c\u1ee7a la-de \u0111\u01b0\u1ee3c x\u1ebfp t\u1eeb I \u0111\u1ebfn IV. V\u1edbi \u0111\u1ed9 I, tia la-de t\u01b0\u01a1ng \u0111\u1ed1i an to\u00e0n. V\u1edbi \u0111\u1ed9 IV, tia la-de c\u00f3 th\u1ec3 l\u00e0m h\u1ecfng m\u1eaft hay b\u1ecfng da. C\u00e1c s\u1ea3n ph\u1ea9m la-de cho \u0111\u1ed3 d\u00e2n d\u1ee5ng nh\u01b0 m\u00e1y \u0111\u1ecdc CD v\u00e0 b\u00fat la-de d\u00f9ng trong l\u1edbp h\u1ecdc \u0111\u01b0\u1ee3c x\u1ebfp h\u1ea1ng an to\u00e0n t\u1eeb I, II, hay III. \t\t\t\t\t\t\t(Ngu\u1ed3n: https:\/\/vi.wikipedia.org\/wiki\/Laser) 66","Ho\u1ea1t \u0111\u1ed9ng 2: C\u00f9ng th\u1ea3o lu\u1eadn * M\u1ee5c ti\u00eau: HS nh\u1eadn bi\u1ebft t\u01b0 th\u1ebf ng\u1ed3i \u0111\u00fang v\u00e0 c\u1ea7n c\u00f3 \u00e1nh s\u00e1ng th\u00edch h\u1ee3p \u0111\u1ec3 h\u1ecdc t\u1eadp. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS quan s\u00e1t h\u00ecnh 14a v\u00e0 14b (SGK, trang 42), th\u1ea3o lu\u1eadn nh\u00f3m 4 \u0111\u1ec3 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: + B\u1ea1n n\u00e0o trong c\u00e1c h\u00ecnh c\u00f3 t\u01b0 th\u1ebf ng\u1ed3i \u0111\u00fang v\u00e0 c\u00f3 \u00e1nh s\u00e1ng th\u00edch h\u1ee3p \u0111\u1ec3 h\u1ecdc t\u1eadp? V\u00ec sao? + Em \u0111\u00e3 th\u1ef1c hi\u1ec7n t\u01b0 th\u1ebf ng\u1ed3i ho\u0323c nh\u01b0 th\u1ebf n\u00e0o \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o kho\u1ea3ng c\u00e1ch ph\u00f9 h\u1ee3p t\u1eeb m\u1eaft \u0111\u1ebfn s\u00e1ch, v\u1edf,... khi \u0111o\u0323c, vi\u1ebft v\u00e0 c\u00f3 \u0111\u1ee7 \u00e1nh s\u00e1ng \u0111\u1ec3 gi\u00fap b\u1ea3o v\u1ec7 m\u1eaft, ph\u00f2ng tr\u00e1nh b\u1ecb c\u1eadn th\u1ecb? + N\u00ean v\u00e0 kh\u00f4ng n\u00ean l\u00e0m g\u00ec \u0111\u1ec3 b\u1ea3o v\u1ec7 m\u1eaft kh\u1ecfi t\u00e1c h\u1ea1i do \u00e1nh s\u00e1ng qu\u00e1 m\u1ea1nh hay \u00e1nh s\u00e1ng qu\u00e1 y\u1ebfu g\u00e2y ra? \u2013 GV m\u1eddi \u0111\u1ea1i di\u1ec7n c\u00e1c nh\u00f3m l\u00ean chia s\u1ebb c\u00e2u tr\u1ea3 l\u1eddi. HS d\u01b0\u1edbi l\u1edbp nh\u1eadn x\u00e9t, b\u1ed5 sung. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: Em ch\u1ecdn t\u01b0 th\u1ebf ng\u1ed3i \u0111\u00fang, \u0111\u1ea3m b\u1ea3o kho\u1ea3ng c\u00e1ch \u0111\u1ecdc, vi\u1ebft ph\u00f9 h\u1ee3p v\u00e0 c\u00f3 \u0111\u1ee7 \u00e1nh s\u00e1ng \u0111\u1ec3 b\u1ea3o v\u1ec7 m\u1eaft, tr\u00e1nh b\u1ecb c\u1eadn th\u1ecb. * Th\u00f4ng tin d\u00e0nh cho GV: T\u00e1c d\u1ee5ng c\u1ee7a \u00e1nh s\u00e1ng: \u2022\t \u00c1nh s\u00e1ng m\u00e0 m\u1eaft con ng\u01b0\u1eddi nh\u00ecn th\u1ea5y (g\u1ecdi l\u00e0 \u00e1nh s\u00e1ng th\u1ea5y \u0111\u01b0\u1ee3c hay \u00e1nh s\u00e1ng kh\u1ea3 ki\u1ebfn) ch\u1ec9 chi\u1ebfm m\u1ed9t v\u00f9ng r\u1ea5t nh\u1ecf c\u1ee7a \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi. Ngo\u00e0i v\u00f9ng \u00e1nh s\u00e1ng th\u1ea5y \u0111\u01b0\u1ee3c n\u00e0y, c\u00f3 nh\u1eefng \u00e1nh s\u00e1ng m\u00e0 m\u1eaft ng\u01b0\u1eddi kh\u00f4ng th\u1ea5y, mang n\u0103ng l\u01b0\u1ee3ng nh\u1ecf h\u01a1n \u00e1nh s\u00e1ng th\u1ea5y \u0111\u01b0\u1ee3c (tia h\u1ed3ng ngo\u1ea1i) ho\u1eb7c l\u1edbn h\u01a1n \u00e1nh s\u00e1ng th\u1ea5y \u0111\u01b0\u1ee3c (tia t\u1eed ngo\u1ea1i hay tia c\u1ef1c t\u00edm). \u2022\t \u00c1nh s\u00e1ng h\u1ed3ng ngo\u1ea1i \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong \u0111\u1eddi s\u1ed1ng h\u1eb1ng ng\u00e0y nh\u01b0 \u0111\u1ec3 s\u1ea5y kh\u00f4 th\u1ef1c ph\u1ea9m, s\u01b0\u1edfi \u1ea5m, chi\u1ebfu trong nh\u1eefng b\u1ed9 \u0111i\u1ec1u khi\u1ec3n t\u1eeb xa nh\u01b0 camera trong b\u00f3ng t\u1ed1i,\u2026 \u2022\t Tia t\u1eed ngo\u1ea1i mang n\u0103ng l\u01b0\u1ee3ng l\u1edbn n\u00ean \u0111\u01b0\u1ee3c d\u00f9ng \u0111\u1ec3 kh\u1eed khu\u1ea9n, k\u00edch th\u00edch s\u1ef1 ph\u00e1t tri\u1ec3n c\u1ee7a x\u01b0\u01a1ng (v\u1edbi li\u1ec1u l\u01b0\u1ee3ng h\u1ee3p l\u00ed),\u2026 Tuy nhi\u00ean, n\u1ebfu b\u1ecb ph\u01a1i d\u01b0\u1edbi n\u1eafng g\u1eaft, c\u01a1 th\u1ec3 s\u1ebd ch\u1ecbu nhi\u1ec1u t\u00e1c h\u1ea1i: b\u1ecb ung th\u01b0 da, ch\u00e1y n\u1eafng, v\u00e0 nh\u1ea5t l\u00e0 t\u0103ng nguy c\u01a1 l\u00e0m t\u1ed5n th\u01b0\u01a1ng v\u00f5ng m\u1ea1c v\u00e0 c\u01b0\u1eddm m\u1eaft. Th\u1eadm ch\u00ed g\u00e2y ra t\u00ecnh tr\u1ea1ng lo\u00e0 hay m\u00f9 m\u1eaft. Ho\u1ea1t \u0111\u1ed9ng 3: B\u1ed1 tr\u00ed g\u00f3c h\u1ecdc t\u1eadp c\u00f3 \u00e1nh s\u00e1ng th\u00edch h\u1ee3p * M\u1ee5c ti\u00eau: HS v\u1eadn d\u1ee5ng ki\u1ebfn th\u1ee9c \u0111\u00e3 h\u1ecdc v\u00e0o vi\u1ec7c b\u1ed1 tr\u00ed g\u00f3c h\u1ecdc t\u1eadp c\u00f3 \u00e1nh s\u00e1ng th\u00edch h\u1ee3p \u0111\u1ec3 tr\u00e1nh b\u1ecb c\u1eadn th\u1ecb. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS: H\u00e3y ki\u1ec3m tra \u0111i\u1ec1u ki\u1ec7n chi\u1ebfu s\u00e1ng \u1edf g\u00f3c h\u1ecdc t\u1eadp c\u1ee7a em. \u2013 GV h\u1ecfi HS: C\u1ea7n l\u00e0m g\u00ec \u0111\u1ec3 g\u00f3c h\u1ecdc t\u1eadp c\u00f3 \u0111\u1ee7 \u00e1nh s\u00e1ng? \u2013 HS tr\u1ea3 l\u1eddi. GV nh\u1eadn x\u00e9t v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: G\u00f3c h\u1ecdc t\u1eadp c\u1ee7a em c\u1ea7n c\u00f3 \u00e1nh s\u00e1ng th\u00edch h\u1ee3p \u0111\u1ec3 tr\u00e1nh b\u1ecb c\u1eadn th\u1ecb. 67","* Th\u00f4ng tin d\u00e0nh cho GV: \u0110i\u1ec1u ki\u1ec7n th\u00edch h\u1ee3p \u0111\u1ec3 \u0111\u1ecdc s\u00e1ch ho\u1eb7c xem m\u00e0n h\u00ecnh c\u00e1c thi\u1ebft b\u1ecb \u0111i\u1ec7n t\u1eed: \u2022\t \u00c1nh s\u00e1ng d\u00f9ng l\u00e0m vi\u1ec7c g\u1ea7n ph\u1ea3i c\u00f3 c\u01b0\u1eddng \u0111\u1ed9 l\u1edbn g\u1ea5p 3 l\u1ea7n c\u01b0\u1eddng \u0111\u1ed9 \u00e1nh s\u00e1ng trong ph\u00f2ng. Kh\u00f4ng n\u00ean ch\u1ec9 d\u00f9ng m\u1ed9t ng\u1ecdn \u0111\u00e8n \u0111\u1ec3 \u0111\u1ecdc s\u00e1ch trong ph\u00f2ng t\u1ed1i. \u2022\t Vi\u1ec7c chi\u1ebfu s\u00e1ng \u0111\u01b0\u1ee3c xem l\u00e0 t\u1ed1t nh\u1ea5t cho vi\u1ec7c \u0111\u1ecdc s\u00e1ch l\u00e0 chi\u1ebfu s\u00e1ng t\u1eeb ph\u00eda tr\u00ean xu\u1ed1ng v\u00e0 t\u1eeb tr\u01b0\u1edbc. \u2022\t Kho\u1ea3ng c\u00e1ch trung b\u00ecnh \u0111\u1ec3 \u0111\u1ecdc s\u00e1ch \u0111\u1ed1i v\u1edbi ng\u01b0\u1eddi l\u1edbn l\u00e0 35 \u2013 40 cm (\u0111\u1ed1i v\u1edbi tr\u1ebb em kho\u1ea3ng c\u00e1ch n\u00e0y s\u1ebd g\u1ea7n h\u01a1n). \u2022\t T\u01b0 th\u1ebf: Ng\u1ed3i ngay ng\u1eafn tr\u00ean b\u00e0n h\u1ecdc ho\u1eb7c b\u00e0n l\u00e0m vi\u1ec7c, ng\u1ef1c v\u00e0 l\u01b0ng th\u1eb3ng khi \u0111\u00f3 m\u1eaft s\u1ebd c\u00e1ch s\u00e1ch ho\u1eb7c m\u00e0n h\u00ecnh m\u00e1y t\u00ednh m\u1ed9t kho\u1ea3ng c\u00e1ch gi\u1ed1ng nhau. \u2022\t Xem truy\u1ec1n h\u00ecnh: Kho\u1ea3ng c\u00e1ch t\u1eeb m\u00e0n h\u00ecnh \u0111\u1ebfn m\u1eaft b\u1eb1ng 7 l\u1ea7n chi\u1ec1u r\u1ed9ng c\u1ee7a m\u00e0n h\u00ecnh ti vi (kho\u1ea3ng 2,5 \u2013 3 m). \t\t\t\t\t(Ngu\u1ed3n: https:\/\/tuoitre.vn\/ve-sinh-thi-giac-169093.htm) \u2013 GV y\u00eau c\u1ea7u HS \u0111\u1ecdc n\u1ed9i dung m\u1ee5c Em \u0111\u00e3 h\u1ecdc \u0111\u01b0\u1ee3c: \u0110\u1ec3 b\u1ea3o v\u1ec7 m\u0103\u0301t v\u00e0 ph\u00f2ng tr\u00e1nh b\u1ecb c\u1eadn th\u1ecb em c\u1ea7n: tr\u00e1nh \u00e1nh s\u00e1ng qu\u00e1 m\u1ea1nh chi\u1ebfu v\u00e0o m\u0103\u0301t; \u0111\u1ecdc, vi\u1ebft d\u01b0\u1edbi \u00e1nh s\u00e1ng th\u00edch h\u1ee3p; th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c t\u01b0 th\u1ebf ng\u1ed3i h\u1ecdc \u0111u\u0301ng, gi\u1eef kho\u1ea3ng c\u00e1ch t\u1eeb m\u0103\u0301t \u0111\u1ebfn s\u00e1ch, v\u1edf,... khi \u0111\u1ecdc, vi\u1ebft ph\u00f9 h\u1ee3p. \u2013 GV y\u00eau c\u1ea7u HS \u0111\u1ecdc c\u00e1c t\u1eeb kho\u00e1 trong b\u00e0i: Chi\u1ebfu s\u00e1ng \u2013 C\u1eadn th\u1ecb \u2013 B\u1ea3o v\u1ec7 m\u1eaft. Ho\u1ea1t \u0111\u1ed9ng ti\u1ebfp n\u1ed1i sau b\u00e0i h\u1ecdc GV y\u00eau c\u1ea7u HS v\u1ec1 nh\u00e0 t\u00ecm hi\u1ec3u v\u1ec1 \u00e2m thanh v\u00e0 s\u1ef1 truy\u1ec1n c\u1ee7a \u00e2m thanh trong kh\u00f4ng kh\u00ed, trong n\u01b0\u1edbc, trong v\u1eadt r\u1eafn. B\u00e0i 10. \u00c2m thanh (2 ti\u1ebft) I. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t Sau b\u00e0i h\u1ecdc, HS: \u2013 L\u1ea5y \u0111\u01b0\u1ee3c v\u00ed d\u1ee5 th\u1ef1c t\u1ebf ho\u1eb7c l\u00e0m th\u00ed nghi\u1ec7m \u0111\u1ec3 minh ho\u1ea1 c\u00e1c v\u1eadt ph\u00e1t ra \u00e2m thanh \u0111\u1ec1u rung \u0111\u1ed9ng. \u2013 N\u00eau \u0111\u01b0\u1ee3c d\u1eabn ch\u1ee9ng v\u1ec1 \u00e2m thanh c\u00f3 th\u1ec3 truy\u1ec1n qua ch\u1ea5t kh\u00ed, ch\u1ea5t l\u1ecfng, ch\u1ea5t r\u1eafn. \u2013 So s\u00e1nh \u0111\u01b0\u1ee3c \u0111\u1ed9 to c\u1ee7a \u00e2m thanh khi l\u1ea1i g\u1ea7n ho\u1eb7c ra xa ngu\u1ed3n \u00e2m. II. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc \u2013 GV: C\u00e1c h\u00ecnh trong b\u00e0i 10 SGK, c\u00e1c d\u1ee5ng c\u1ee5 li\u1ec7t k\u00ea trong b\u00e0i: + Ti\u1ebft 1: Th\u01b0\u1edbc nh\u1ef1a c\u1ee9ng, m\u1ecfng, d\u00e2y cao su. Th\u00eca (mu\u1ed7ng), ch\u1eadu ho\u1eb7c n\u1ed3i b\u1eb1ng kim lo\u1ea1i, s\u00e1u c\u1ed1c thu\u1ef7 tinh gi\u1ed1ng nhau, m\u1ed9t chai n\u01b0\u1edbc, m\u1ed9t th\u00eca kim lo\u1ea1i. + Ti\u1ebft 2: M\u1ed9t ch\u1eadu n\u01b0\u1edbc, hai chi\u1ebfc th\u00eca kim lo\u1ea1i, m\u1ed9t b\u00e0n g\u1ed7. \u1ed0ng gi\u1ea5y ho\u1eb7c \u1ed1ng nh\u1ef1a, hai ph\u1ec5u, b\u0103ng d\u00e1n, k\u00e9o. 68","+ Ghi ch\u00fa: GV c\u00f3 th\u1ec3 kh\u00f4ng th\u1ef1c hi\u1ec7n m\u1ed9t s\u1ed1 th\u00ed nghi\u1ec7m m\u00e0 thay b\u1eb1ng ho\u1ea1t \u0111\u1ed9ng xem video clip v\u1ec1 c\u00e1c th\u00ed nghi\u1ec7m. \u2013 HS: SGK, VBT. III. C\u00c1C Ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc Ti\u1ebft 1 Ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng * M\u1ee5c ti\u00eau: T\u1ea1o h\u1ee9ng th\u00fa v\u00e0 kh\u01a1i g\u1ee3i nh\u1eefng hi\u1ec3u bi\u1ebft \u0111\u00e3 c\u00f3 c\u1ee7a HS v\u1ec1 vai tr\u00f2 c\u1ee7a \u00e2m thanh. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV t\u1ed5 ch\u1ee9c cho HS ch\u01a1i tr\u00f2 ch\u01a1i: \u201cAi n\u00f3i \u0111\u1ea5y?\u201d \u2013 GV ph\u1ed5 bi\u1ebfn lu\u1eadt ch\u01a1i: M\u1ed9t b\u1ea1n l\u1ea5y tay b\u1ecbt m\u1eaft, b\u1ed1n b\u1ea1n kh\u00e1c \u0111\u1ee9ng xung quanh. M\u1ed9t trong b\u1ed1n b\u1ea1n n\u00e0y g\u1ecdi t\u00ean b\u1ea1n \u0111ang b\u1ecbt m\u1eaft. B\u1ea1n b\u1ecbt m\u1eaft \u0111o\u00e1n t\u00ean c\u1ee7a b\u1ea1n v\u1eeba g\u1ecdi m\u00ecnh. N\u1ebfu \u0111o\u00e1n \u0111\u00fang, HS b\u1ecbt m\u1eaft s\u1ebd \u0111\u01b0\u1ee3c b\u00f4ng hoa khen ng\u1ee3i. \u2013 GV \u0111\u1eb7t c\u00e2u h\u1ecfi: Nh\u1edd v\u00e0o \u0111\u00e2u m\u00e0 b\u1ea1n b\u1ecbt m\u1eaft \u0111o\u00e1n \u0111\u01b0\u1ee3c ai v\u1eeba g\u1ecdi t\u00ean m\u00ecnh? \u2013 GV y\u00eau c\u1ea7u m\u1ed9t v\u00e0i HS tr\u1ea3 l\u1eddi. \u2013 GV nh\u1eadn x\u00e9t chung v\u00e0 d\u1eabn d\u1eaft v\u00e0o b\u00e0i h\u1ecdc: \u201c\u00c2m thanh\u201d. Ho\u1ea1t \u0111\u1ed9ng 1: Th\u00ed nghi\u1ec7m: Khi n\u00e0o th\u00ec m\u1ed9t v\u1eadt ph\u00e1t ra \u00e2m thanh? * M\u1ee5c ti\u00eau: HS l\u00e0m \u0111\u01b0\u1ee3c th\u00ed nghi\u1ec7m minh ho\u1ea1 c\u00e1c v\u1eadt ph\u00e1t ra \u00e2m thanh \u0111\u1ec1u rung \u0111\u1ed9ng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 4 v\u00e0 giao nhi\u1ec7m v\u1ee5 cho m\u1ed7i nh\u00f3m th\u1ef1c hi\u1ec7n th\u00ed nghi\u1ec7m nh\u01b0 h\u00ecnh 2 v\u00e0 3 (SGK, trang 43). \u2013 GV quan s\u00e1t c\u00e1c nh\u00f3m l\u00e0m th\u00ed nghi\u1ec7m, \u0111\u1eb7t c\u00e1c c\u00e2u h\u1ecfi: + Em c\u00f3 nghe th\u1ea5y \u00e2m thanh t\u1eeb c\u00e2y th\u01b0\u1edbc v\u00e0 t\u1eeb d\u00e2y cao su kh\u00f4ng? + Th\u01b0\u1edbc v\u00e0 d\u00e2y cao su c\u00f3 rung \u0111\u1ed9ng kh\u00f4ng? Em c\u00f3 th\u1ec3 k\u1ebft lu\u1eadn g\u00ec v\u1ec1 m\u1ed1i li\u00ean h\u1ec7 gi\u1eefa s\u1ef1 ph\u00e1t ra \u00e2m thanh v\u00e0 s\u1ef1 rung \u0111\u1ed9ng c\u1ee7a v\u1eadt? \u2013 GV m\u1eddi HS tr\u1ea3 l\u1eddi. \u2013 HS nh\u1eadn x\u00e9t l\u1eabn nhau. GV h\u01b0\u1edbng d\u1eabn HS r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: V\u1eadt rung \u0111\u1ed9ng khi ph\u00e1t ra \u00e2m thanh. Ho\u1ea1t \u0111\u1ed9ng 2: C\u00f9ng th\u1ea3o lu\u1eadn: X\u00e1c \u0111\u1ecbnh ngu\u1ed3n \u00e2m * M\u1ee5c ti\u00eau: HS nh\u1eadn x\u00e9t v\u00e0 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c ngu\u1ed3n \u00e2m trong m\u1ed9t s\u1ed1 tr\u01b0\u1eddng h\u1ee3p c\u1ee5 th\u1ec3. * C\u00e1ch ti\u1ebfn h\u00e0nh: a) V\u1eadt rung khi ph\u00e1t ra \u00e2m thanh \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 6 v\u00e0 giao nhi\u1ec7m v\u1ee5 cho m\u1ed7i nh\u00f3m th\u1ef1c h\u00e0nh th\u00ed nghi\u1ec7m nh\u01b0 h\u00ecnh 4 (SGK, trang 44), sau \u0111\u00f3 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: + V\u1eadt n\u00e0o l\u00e0 ngu\u1ed3n \u00e2m? + V\u1eadt n\u00e0y c\u00f3 rung \u0111\u1ed9ng khi ph\u00e1t ra \u00e2m thanh kh\u00f4ng? 69","G\u1ee3i \u00fd: Ch\u1eadu ho\u1eb7c n\u1ed3i b\u1eb1ng kim lo\u1ea1i l\u00e0 ngu\u1ed3n \u00e2m. V\u1eadt n\u00e0y rung \u0111\u1ed9ng khi ph\u00e1t ra \u00e2m thanh. \u2013 GV m\u1eddi HS tr\u1ea3 l\u1eddi. \u2013 HS nh\u1eadn x\u00e9t l\u1eabn nhau. b) \u00c2m thanh ph\u00e1t ra t\u1eeb hai d\u00e2y thanh trong thanh qu\u1ea3n \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 6 v\u00e0 giao nhi\u1ec7m v\u1ee5 cho m\u1ed7i nh\u00f3m th\u1ef1c h\u00e0nh th\u00ed nghi\u1ec7m nh\u01b0 h\u00ecnh 5 (SGK, trang 44), sau \u0111\u00f3 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: + Khi ch\u00fang ta n\u00f3i th\u00ec b\u1ed9 ph\u1eadn n\u00e0o c\u1ee7a c\u01a1 th\u1ec3 \u0111\u00f3ng vai tr\u00f2 l\u00e0 ngu\u1ed3n \u00e2m? + Hai d\u00e2y thanh trong thanh qu\u1ea3n n\u00e0y c\u00f3 rung \u0111\u1ed9ng khi ta n\u00f3i kh\u00f4ng? L\u00e0m c\u00e1ch n\u00e0o \u0111\u1ec3 bi\u1ebft \u0111i\u1ec1u n\u00e0y? \u2013 GV m\u1eddi HS tr\u1ea3 l\u1eddi. \u2013 HS nh\u1eadn x\u00e9t l\u1eabn nhau. GV h\u01b0\u1edbng d\u1eabn HS r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: Ngu\u1ed3n \u00e2m (nh\u01b0 hai d\u00e2y thanh) rung \u0111\u1ed9ng khi ph\u00e1t ra \u00e2m thanh. * Th\u00f4ng tin d\u00e0nh cho GV: Ch\u1ee9c n\u0103ng v\u00e0 ho\u1ea1t \u0111\u1ed9ng c\u1ee7a thanh qu\u1ea3n: \u2022\t Thanh qu\u1ea3n l\u00e0 c\u01a1 quan trong c\u1ed5, chi\u1ebfm m\u1ed9t \u0111o\u1ea1n c\u1ee7a h\u1ec7 h\u00f4 h\u1ea5p \u1edf ng\u01b0\u1eddi v\u00e0 m\u1ed9t s\u1ed1 \u0111\u1ed9ng v\u1eadt b\u1ed1n ch\u00e2n, \u0111\u1ec3 ph\u00e1t \u00e2m v\u00e0 \u0111\u1ec3 th\u1edf. \u2022\t Ngo\u00e0i ch\u1ee9c n\u0103ng h\u00f4 h\u1ea5p, b\u1ea3o v\u1ec7 \u0111\u01b0\u1eddng h\u00f4 h\u1ea5p d\u01b0\u1edbi (ph\u00f2ng ng\u1eeba d\u1ecb v\u1eadt x\u00e2m nh\u1eadp v\u00e0o ph\u1ed5i b\u1eb1ng c\u00e1ch ho v\u00e0 c\u00e1c h\u00e0nh \u0111\u1ed9ng ph\u1ea3n x\u1ea1 kh\u00e1c nh\u1eb1m \u0111\u1ea9y d\u1ecb v\u1eadt ra kh\u1ecfi \u0111\u01b0\u1eddng h\u00f4 h\u1ea5p), thanh qu\u1ea3n c\u00f3 ch\u1ee9c n\u0103ng quan tr\u1ecdng l\u00e0 g\u00f3p ph\u1ea7n t\u1ea1o n\u00ean gi\u1ecdng n\u00f3i \u2013 ng\u00f4n ng\u1eef \u0111\u1ec3 con ng\u01b0\u1eddi giao ti\u1ebfp. \u2022\t Lu\u1ed3ng kh\u00ed \u0111\u01b0\u1ee3c \u0111\u1ea9y t\u1eeb ph\u1ed5i ra ngo\u00e0i l\u00e0m rung chuy\u1ec3n d\u00e2y thanh t\u1eeb \u0111\u00f3 ph\u00e1t ra \u00e2m thanh. \u00c2m thanh ph\u00e1t ra thay \u0111\u1ed5i khi n\u00f3 \u0111i qua \u0111\u01b0\u1eddng h\u00f4 h\u1ea5p, \u0111\u01b0\u1ee3c c\u1ea5u h\u00ecnh kh\u00e1c nhau d\u1ef1a tr\u00ean v\u1ecb tr\u00ed c\u1ee7a l\u01b0\u1ee1i, m\u00f4i, mi\u1ec7ng v\u00e0 h\u1ea7u h\u1ecdng (h\u00ecnh 1 d\u01b0\u1edbi \u0111\u00e2y). \t\t\t (Ngu\u1ed3n: https:\/\/www.vinmec.com\/vi\/co\u2013the\u2013nguoi\/thanh\u2013quan\u201352\/) Thanh qu\u1ea3n D\u00e2y thanh 2 1 \u2013 GV c\u00f3 th\u1ec3 h\u01b0\u1edbng d\u1eabn HS l\u00e0m th\u00ed nghi\u1ec7m m\u00f4 ph\u1ecfng hai d\u00e2y thanh nh\u01b0 sau: + D\u1ee5ng c\u1ee5: Hai m\u1ea3nh cao su m\u1ecfng c\u00f9ng k\u00edch th\u01b0\u1edbc ho\u1eb7c m\u1ed9t m\u1ea3nh gi\u1ea5y c\u00f3 kho\u00e9t l\u1ed7 tr\u00f2n, g\u1ea5p nh\u01b0 h\u00ecnh 2. + Th\u1ef1c hi\u1ec7n: K\u1eb9p hai m\u1ea3nh cao su ho\u1eb7c hai \u0111\u1ea7u m\u1ea3nh gi\u1ea5y s\u00e1t nhau v\u00e0 th\u1ed5i qua khe h\u1edf. 70","Ho\u1ea1t \u0111\u1ed9ng 3: \u0110i\u1ec7u nh\u1ea1c trong c\u00e1c c\u1ed1c thu\u1ef7 tinh * M\u1ee5c ti\u00eau: HS th\u1ef1c h\u00e0nh th\u00ed nghi\u1ec7m t\u1ea1o \u00e2m thanh v\u1edbi c\u00e1c c\u1ed1c ch\u1ee9a n\u01b0\u1edbc. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 6 v\u00e0 y\u00eau c\u1ea7u HS th\u1ef1c hi\u1ec7n th\u00ed nghi\u1ec7m nh\u01b0 h\u01b0\u1edbng d\u1eabn \u1edf trang 44 SGK. \u2013 GV \u0111\u1eb7t c\u00e1c c\u00e2u h\u1ecfi \u0111\u1ec3 HS th\u1ea3o lu\u1eadn: + Khi g\u00f5 th\u00eca v\u00e0o m\u1ed7i c\u1ed1c, \u00e2m thanh \u1edf m\u1ed7i c\u1ed1c ph\u00e1t ra nh\u01b0 th\u1ebf n\u00e0o? + V\u00ec sao \u00e2m thanh ph\u00e1t ra t\u1eeb m\u1ed7i c\u1ed1c l\u1ea1i kh\u00e1c nhau? * K\u1ebft lu\u1eadn: \u00c2m thanh ph\u00e1t ra t\u1eeb m\u1ed7i c\u1ed1c kh\u00e1c nhau khi l\u01b0\u1ee3ng n\u01b0\u1edbc trong m\u1ed7i c\u1ed1c kh\u00e1c nhau. \u2013 GV y\u00eau c\u1ea7u HS \u0111\u1ecdc n\u1ed9i dung Em \u0111\u00e3 h\u1ecdc \u0111\u01b0\u1ee3c: C\u00e1c v\u1eadt ph\u00e1t ra \u00e2m thanh \u0111\u1ec1u rung \u0111\u1ed9ng. V\u1eadt ph\u00e1t ra \u00e2m thanh \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 ngu\u1ed3n \u00e2m. \u2013 GV t\u1ed5 ch\u1ee9c cho HS \u0111\u1ecdc m\u1ee5c Em t\u00ecm hi\u1ec3u th\u00eam \u0111\u1ec3 HS hi\u1ec3u c\u01a1 ch\u1ebf c\u1ee7a vi\u1ec7c nghe \u0111\u01b0\u1ee3c do m\u00e0ng nh\u0129 trong tai. \u2013 GV \u0111\u1eb7t th\u00eam c\u00e2u h\u1ecfi m\u1edf r\u1ed9ng v\u00e0 y\u00eau c\u1ea7u HS tr\u1ea3 l\u1eddi: + Tai ch\u00fang ta nghe \u0111\u01b0\u1ee3c nh\u1edd b\u1ed9 ph\u1eadn n\u00e0o c\u00f3 trong tai? B\u1ed9 ph\u1eadn n\u00e0y c\u00f3 rung \u0111\u1ed9ng khi nh\u1eadn \u0111\u01b0\u1ee3c \u00e2m thanh kh\u00f4ng? + Ch\u00fang ta c\u1ea7n b\u1ea3o v\u1ec7 m\u00e0ng nh\u0129 nh\u01b0 th\u1ebf n\u00e0o? G\u1ee3i \u00fd: Khi \u00e2m thanh \u0111\u01b0\u1ee3c truy\u1ec1n v\u00e0o b\u00ean trong tai c\u1ee7a ch\u00fang ta, \u00e2m thanh l\u00e0m m\u00e0ng nh\u0129 trong tai rung \u0111\u1ed9ng gi\u00fap ch\u00fang ta nghe \u0111\u01b0\u1ee3c. Ch\u00fang ta c\u1ea7n gi\u1eef v\u1ec7 sinh tai, kh\u00f4ng l\u00e0m m\u00e0ng nh\u0129 b\u1ecb t\u1ed5n th\u01b0\u01a1ng \u0111\u1ec3 tr\u00e1nh b\u1ecb b\u1ec7nh \u0111i\u1ebfc. Ti\u1ebft 2 Ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng * M\u1ee5c ti\u00eau: T\u1ea1o h\u1ee9ng th\u00fa v\u00e0 kh\u01a1i g\u1ee3i nh\u1eefng hi\u1ec3u bi\u1ebft \u0111\u00e3 c\u00f3 c\u1ee7a HS v\u1ec1 s\u1ef1 lan truy\u1ec1n c\u1ee7a \u00e2m thanh. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV \u0111\u1eb7t c\u00e2u h\u1ecfi: \u00c2m thanh c\u00f3 th\u1ec3 truy\u1ec1n trong nh\u1eefng m\u00f4i tr\u01b0\u1eddng n\u00e0o? \u2013 GV m\u1eddi m\u1ed9t v\u00e0i HS tr\u1ea3 l\u1eddi c\u00e1 nh\u00e2n. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 d\u1eabn d\u1eaft v\u00e0o ti\u1ebft 2 c\u1ee7a b\u00e0i. Ho\u1ea1t \u0111\u1ed9ng 1: Th\u00ed nghi\u1ec7m: \u00c2m thanh c\u00f3 th\u1ec3 truy\u1ec1n \u0111\u01b0\u1ee3c trong c\u00e1c m\u00f4i tr\u01b0\u1eddng kh\u00e1c nhau * M\u1ee5c ti\u00eau: HS th\u1ef1c hi\u1ec7n m\u1ed9t s\u1ed1 th\u00ed nghi\u1ec7m \u0111\u1ec3 t\u00ecm hi\u1ec3u v\u1ec1 nh\u1eefng m\u00f4i tr\u01b0\u1eddng m\u00e0 \u00e2m thanh c\u00f3 th\u1ec3 truy\u1ec1n trong \u0111\u00f3. * C\u00e1ch ti\u1ebfn h\u00e0nh: a) \u00c2m thanh c\u00f3 truy\u1ec1n \u0111\u01b0\u1ee3c trong v\u1eadt r\u1eafn kh\u00f4ng? \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 6 v\u00e0 y\u00eau c\u1ea7u HS th\u1ef1c hi\u1ec7n th\u00ed nghi\u1ec7m nh\u01b0 h\u01b0\u1edbng d\u1eabn \u1edf h\u00ecnh 7 (SGK, trang 45). 71","\u2013 GV \u0111\u1eb7t c\u00e2u h\u1ecfi \u0111\u1ec3 c\u00e1c nh\u00f3m th\u1ea3o lu\u1eadn: + Em c\u00f3 nghe ti\u1ebfng g\u00f5 c\u1ee7a tay kh\u00f4ng? L\u00fac \u0111\u00f3, m\u1eb7t b\u00e0n c\u00f3 rung \u0111\u1ed9ng kh\u00f4ng? + T\u1eeb th\u00ed nghi\u1ec7m tr\u00ean, em k\u1ebft lu\u1eadn \u0111\u01b0\u1ee3c g\u00ec v\u1ec1 s\u1ef1 lan truy\u1ec1n c\u1ee7a \u00e2m thanh qua g\u1ed7? * K\u1ebft lu\u1eadn: \u00c2m thanh truy\u1ec1n \u0111\u01b0\u1ee3c trong g\u1ed7. b) \u00c2m thanh c\u00f3 truy\u1ec1n \u0111\u01b0\u1ee3c trong n\u01b0\u1edbc kh\u00f4ng? \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 6 v\u00e0 y\u00eau c\u1ea7u HS th\u1ef1c hi\u1ec7n th\u00ed nghi\u1ec7m nh\u01b0 h\u01b0\u1edbng d\u1eabn \u1edf h\u00ecnh 8 (SGK, trang 45). \u2013 GV \u0111\u1eb7t c\u00e2u h\u1ecfi \u0111\u1ec3 c\u00e1c nh\u00f3m th\u1ea3o lu\u1eadn: + Em c\u00f3 nghe ti\u1ebfng hai chi\u1ebfc th\u00eca trong n\u01b0\u1edbc ch\u1ea1m nhau kh\u00f4ng? + \u0110i\u1ec1u \u0111\u00f3 ch\u1ee9ng t\u1ecf \u00e2m thanh truy\u1ec1n \u0111\u01b0\u1ee3c trong nh\u1eefng m\u00f4i tr\u01b0\u1eddng n\u00e0o? \u2013 GV y\u00eau c\u1ea7u HS r\u00fat ra k\u1ebft lu\u1eadn v\u1ec1 s\u1ef1 lan truy\u1ec1n c\u1ee7a \u00e2m thanh trong ch\u1ea5t l\u1ecfng nh\u01b0 n\u01b0\u1edbc v\u00e0 trong ch\u1ea5t r\u1eafn nh\u01b0 g\u1ed7 t\u1eeb c\u00e1c th\u00ed nghi\u1ec7m tr\u00ean. * K\u1ebft lu\u1eadn: \u00c2m thanh truy\u1ec1n \u0111\u01b0\u1ee3c trong n\u01b0\u1edbc, v\u1eadt r\u1eafn. Ho\u1ea1t \u0111\u1ed9ng 2: C\u00f9ng th\u1ea3o lu\u1eadn * M\u1ee5c ti\u00eau: HS bi\u1ebft v\u1eadn d\u1ee5ng nh\u1eefng ki\u1ebfn th\u1ee9c v\u1ec1 s\u1ef1 truy\u1ec1n c\u1ee7a \u00e2m thanh trong c\u00e1c m\u00f4i tr\u01b0\u1eddng kh\u00e1c nhau \u0111\u1ec3 gi\u1ea3i th\u00edch \u0111\u01b0\u1ee3c m\u1ed9t s\u1ed1 t\u00ecnh hu\u1ed1ng th\u1ef1c t\u1ebf c\u1ee7a \u0111\u1eddi s\u1ed1ng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV t\u1ed5 ch\u1ee9c cho HS l\u00e0m vi\u1ec7c nh\u00f3m \u0111\u00f4i, th\u1ea3o lu\u1eadn v\u00e0 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: Trong c\u00e1c tr\u01b0\u1eddng h\u1ee3p sau, \u00e2m thanh c\u00f3 th\u1ec3 truy\u1ec1n \u0111\u01b0\u1ee3c trong m\u00f4i tr\u01b0\u1eddng n\u00e0o? + Nghe ti\u1ebfng th\u1ea7y c\u00f4 gi\u1ea3ng b\u00e0i trong l\u1edbp. (G\u1ee3i \u00fd: \u00c2m thanh truy\u1ec1n \u0111\u01b0\u1ee3c trong kh\u00f4ng kh\u00ed). + Nghe \u0111\u01b0\u1ee3c ti\u1ebfng n\u00f3i v\u1edbi \u0111i\u1ec7n tho\u1ea1i t\u1ef1 l\u00e0m b\u1eb1ng d\u00e2y v\u00e0 h\u1ed9p. (G\u1ee3i \u00fd: \u00c2m thanh truy\u1ec1n \u0111\u01b0\u1ee3c trong v\u1eadt r\u1eafn (d\u00e2y v\u00e0 h\u1ed9p)). * K\u1ebft lu\u1eadn: \u00c2m thanh truy\u1ec1n \u0111\u01b0\u1ee3c qua ch\u1ea5t kh\u00ed, ch\u1ea5t l\u1ecfng v\u00e0 ch\u1ea5t r\u1eafn. Ho\u1ea1t \u0111\u1ed9ng 3: \u00c2m thanh nghe l\u1edbn khi ngu\u1ed3n \u00e2m \u1edf g\u1ea7n v\u00e0 nghe nh\u1ecf khi ngu\u1ed3n \u00e2m \u1edf xa * M\u1ee5c ti\u00eau: HS so s\u00e1nh \u0111\u01b0\u1ee3c \u0111\u1ed9 to c\u1ee7a \u00e2m thanh khi l\u1ea1i g\u1ea7n ho\u1eb7c ra xa ngu\u1ed3n \u00e2m. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV t\u1ed5 ch\u1ee9c cho HS quan s\u00e1t h\u00ecnh 10 (SGK, trang 46) v\u00e0 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: + Khi b\u1ea1n H\u00f9ng n\u00f3i chuy\u1ec7n, b\u1ea1n An hay b\u1ea1n Hoa nghe r\u00f5 h\u01a1n? V\u00ec sao? + Em k\u1ebft lu\u1eadn \u0111\u01b0\u1ee3c g\u00ec v\u1ec1 \u0111\u1ed9 to c\u1ee7a \u00e2m thanh khi ng\u01b0\u1eddi nghe \u1edf g\u1ea7n ngu\u1ed3n \u00e2m h\u01a1n? * K\u1ebft lu\u1eadn: \u00c2m thanh nghe l\u1edbn khi ngu\u1ed3n \u00e2m \u1edf g\u1ea7n v\u00e0 nghe nh\u1ecf khi ngu\u1ed3n \u00e2m \u1edf xa. * Th\u00f4ng tin d\u00e0nh cho GV: \u0110\u1eb7c tr\u01b0ng c\u1ee7a \u00e2m thanh v\u00e0 s\u1ef1 lan truy\u1ec1n c\u1ee7a \u00e2m thanh: \u2022\t \u00c2m thanh l\u00e0 m\u1ed9t d\u1ea1ng c\u1ee7a n\u0103ng l\u01b0\u1ee3ng, c\u0169ng nh\u01b0 \u00e1nh s\u00e1ng v\u00e0 nhi\u1ec7t. \u00c2m thanh sinh ra do dao \u0111\u1ed9ng c\u1ee7a c\u00e1c ph\u1ea7n t\u1eed (nguy\u00ean t\u1eed, ph\u00e2n t\u1eed) trong m\u00f4i tr\u01b0\u1eddng \u0111\u00e0n h\u1ed3i. 72","\u2022\t Do trong ch\u00e2n kh\u00f4ng kh\u00f4ng t\u1ed3n t\u1ea1i b\u1ea5t c\u1ee9 ph\u1ea7n t\u1eed n\u00e0o n\u00ean \u00e2m thanh kh\u00f4ng truy\u1ec1n \u0111\u01b0\u1ee3c trong ch\u00e2n kh\u00f4ng. \u2022\t \u00c2m thanh truy\u1ec1n trong ch\u1ea5t r\u1eafn v\u1edbi t\u1ed1c \u0111\u1ed9 l\u1edbn h\u01a1n trong ch\u1ea5t l\u1ecfng v\u00e0 ch\u1ea5t kh\u00ed do c\u00e1c ph\u1ea7n t\u1eed c\u1ee7a ch\u1ea5t r\u1eafn li\u00ean k\u1ebft v\u1edbi nhau ch\u1eb7t ch\u1ebd h\u01a1n v\u00e0 ch\u1ea5t r\u1eafn \u0111\u1eadm \u0111\u1eb7c h\u01a1n ch\u1ea5t l\u1ecfng v\u00e0 ch\u1ea5t kh\u00ed. \u2022\t T\u1ed1c \u0111\u1ed9 lan truy\u1ec1n c\u1ee7a \u00e2m thanh trong kh\u00f4ng kh\u00ed ph\u1ee5 thu\u1ed9c nhi\u1ec1u y\u1ebfu t\u1ed1 kh\u00e1c nhau nh\u01b0 nhi\u1ec7t \u0111\u1ed9, \u00e1p su\u1ea5t,\u2026 nh\u01b0ng t\u1ed5ng qu\u00e1t th\u00ec kho\u1ea3ng b\u1eb1ng 340 m\/s. T\u1ed1c \u0111\u1ed9 lan truy\u1ec1n c\u1ee7a \u00e2m thanh trong \u0111\u1ed3ng l\u00ean \u0111\u1ebfn 4 600 m\/s. \u2022\t M\u1ed7i \u00e2m thanh \u0111\u01b0\u1ee3c \u0111\u1eb7c tr\u01b0ng b\u1edfi c\u00e1c \u0111\u1ea1i l\u01b0\u1ee3ng nh\u01b0 \u0111\u1ed9 cao, \u0111\u1ed9 to v\u00e0 \u00e2m s\u1eafc (c\u00e1ch th\u1ee9c dao \u0111\u1ed9ng). V\u00ed d\u1ee5: \u1ede h\u00ecnh b\u00ean d\u01b0\u1edbi, ta th\u1ea5y d\u1ea1ng dao \u0111\u1ed9ng c\u1ee7a k\u00e8n c\u1edd-la-ri-n\u00e9t (clarinet) v\u00e0 k\u00e8n tr\u00f4ng-pet (trompette) kh\u00f4ng gi\u1ed1ng nhau. \u00c2m s\u1eafc l\u00e0 c\u01a1 s\u1edf \u0111\u1ec3 ta c\u00f3 th\u1ec3 ph\u00e2n bi\u1ec7t \u0111\u01b0\u1ee3c gi\u1ecdng n\u00f3i c\u1ee7a hai ng\u01b0\u1eddi kh\u00e1c nhau. K\u00e8n clarinet K\u00e8n trompette Ho\u1ea1t \u0111\u1ed9ng 4: C\u00f9ng s\u00e1ng t\u1ea1o: T\u1ef1 l\u00e0m \u1ed1ng nghe y t\u1ebf * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 4 v\u00e0 t\u1ed5 ch\u1ee9c cho m\u1ed7i nh\u00f3m th\u1ef1c h\u00e0nh l\u00e0m \u1ed1ng nghe y t\u1ebf \u0111\u01a1n nh\u01b0 h\u01b0\u1edbng d\u1eabn \u1edf SGK trang 46. \u2013 GV \u0111\u1ec1 ngh\u1ecb c\u00e1c nh\u00f3m d\u00f9ng \u1ed1ng nghe \u0111\u1ec3 \u0111\u1ebfm nh\u1ecbp tim. \u2013 GV \u0111\u1eb7t c\u00e1c c\u00e2u h\u1ecfi v\u00e0 \u0111\u1ec1 ngh\u1ecb c\u00e1c nh\u00f3m th\u1ea3o lu\u1eadn \u0111\u1ec3 tr\u1ea3 l\u1eddi: + Ti\u1ebfng \u0111\u1ed9ng em nghe \u0111\u01b0\u1ee3c l\u00e0 ti\u1ebfng g\u00ec? + V\u00ec sao em nghe \u0111\u01b0\u1ee3c ti\u1ebfng \u0111\u1ed9ng \u0111\u00f3? + Em c\u00f3 th\u1ec3 \u0111\u1ebfm nh\u1ecbp \u0111\u1eadp c\u1ee7a tim kh\u00f4ng? \u2013 GV m\u1eddi \u0111\u1ea1i di\u1ec7n c\u1ee7a m\u1ed9t v\u00e0i nh\u00f3m chia s\u1ebb n\u1ed9i dung th\u1ea3o lu\u1eadn c\u1ee7a nh\u00f3m m\u00ecnh. L\u01b0u \u00fd: GV c\u00f3 th\u1ec3 y\u00eau c\u1ea7u HS t\u1ef1 l\u00e0m \u1ed1ng nghe y t\u1ebf n\u00e0y \u1edf nh\u00e0 v\u00e0 \u0111em l\u00ean l\u1edbp tr\u00ecnh b\u00e0y. \u2013 GV y\u00eau c\u1ea7u HS \u0111\u1ecdc m\u1ee5c Em \u0111\u00e3 h\u1ecdc \u0111\u01b0\u1ee3c: \u00c2m thanh truy\u1ec1n \u0111\u01b0\u1ee3c qua ch\u1ea5t kh\u00ed, ch\u1ea5t l\u1ecfng v\u00e0 ch\u1ea5t r\u0103\u0301n. Khi \u00e2m thanh lan truy\u1ec1n ra c\u00e0ng xa th\u00ec \u0111\u1ed9 to c\u00e0ng gi\u1ea3m. \u2013 GV d\u1eabn d\u1eaft \u0111\u1ec3 HS n\u00eau \u0111\u01b0\u1ee3c c\u00e1c t\u1eeb kho\u00e1 c\u1ee7a b\u00e0i: \u00c2m thanh \u2013 Ngu\u1ed3n \u00e2m \u2013 Rung \u0111\u1ed9ng. Ho\u1ea1t \u0111\u1ed9ng ti\u1ebfp n\u1ed1i sau b\u00e0i h\u1ecdc GV y\u00eau c\u1ea7u HS v\u1ec1 nh\u00e0 t\u00ecm hi\u1ec3u v\u1ec1 vi\u1ec7c s\u1eed d\u1ee5ng \u00e2m thanh trong \u0111\u1eddi s\u1ed1ng \u0111\u1ec3 chu\u1ea9n b\u1ecb cho ti\u1ebft h\u1ecdc sau. 73","B\u00e0i 11. \u00c2M THANH TRONG \u0110\u1edcI S\u1ed0NG (2 ti\u1ebft) I. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t Sau b\u00e0i h\u1ecdc, HS: \u2013 Tr\u00ecnh b\u00e0y \u0111\u01b0\u1ee3c \u00edch l\u1ee3i c\u1ee7a \u00e2m thanh trong cu\u1ed9c s\u1ed1ng. \u2013 Thu th\u1eadp, so s\u00e1nh v\u00e0 tr\u00ecnh b\u00e0y \u0111\u01b0\u1ee3c \u1edf m\u1ee9c \u0111\u1ed9 \u0111\u01a1n gi\u1ea3n th\u00f4ng tin v\u1ec1 m\u1ed9t s\u1ed1 nh\u1ea1c c\u1ee5 th\u01b0\u1eddng g\u1eb7p (m\u1ed9t s\u1ed1 b\u1ed9 ph\u1eadn ch\u00ednh, c\u00e1ch l\u00e0m ph\u00e1t ra \u00e2m thanh). \u2013 Tr\u00ecnh b\u00e0y \u0111\u01b0\u1ee3c t\u00e1c h\u1ea1i c\u1ee7a ti\u1ebfng \u1ed3n v\u00e0 m\u1ed9t s\u1ed1 bi\u1ec7n ph\u00e1p ch\u1ed1ng \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n. \u2013 Th\u1ef1c hi\u1ec7n c\u00e1c quy \u0111\u1ecbnh gi\u1eef tr\u1eadt t\u1ef1 n\u01a1i c\u00f4ng c\u1ed9ng; bi\u1ebft c\u00e1ch ph\u00f2ng ch\u1ed1ng \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n trong cu\u1ed9c s\u1ed1ng. II. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc \u2013 GV: C\u00e1c h\u00ecnh trong b\u00e0i 11 SGK; c\u00e1c d\u1ee5ng c\u1ee5 d\u00f9ng cho ti\u1ebft 1 nh\u01b0 \u0111\u00e0n ghi ta, k\u00e8n ha-m\u00f4-ni-ca (harmonica) ho\u1eb7c s\u00e1o, m\u1ed9t v\u00e0i nh\u1ea1c c\u1ee5 kh\u00e1c nh\u01b0 tr\u1ed1ng, k\u1ebbng tam gi\u00e1c,\u2026 M\u1ed9t h\u1ed9p gi\u1ea5y k\u00edn, k\u00e9o, m\u1ed9t t\u1edd gi\u1ea5y, b\u1ed1n s\u1ee3i d\u00e2y cao su v\u1edbi \u0111\u1ed9 d\u00e0y kh\u00e1c nhau v\u00e0 \u0111\u1ee7 d\u00e0i \u0111\u1ec3 bao quanh h\u1ed9p gi\u1ea5y, hai chi\u1ebfc b\u00fat ch\u00ec. Ghi ch\u00fa: GV c\u00f3 th\u1ec3 l\u01b0\u1ee3c b\u1ecf m\u1ed9t s\u1ed1 th\u00ed nghi\u1ec7m v\u00e0 thay b\u1eb1ng video clip. \u2013 HS: SGK, VBT. III. C\u00c1C Ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc Ti\u1ebft 1 Ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng * M\u1ee5c ti\u00eau: T\u1ea1o h\u1ee9ng th\u00fa v\u00e0 kh\u01a1i g\u1ee3i nh\u1eefng hi\u1ec3u bi\u1ebft \u0111\u00e3 c\u00f3 c\u1ee7a HS v\u1ec1 nh\u1eefng \u00e2m thanh nghe \u0111\u01b0\u1ee3c h\u1eb1ng ng\u00e0y. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV \u0111\u1eb7t c\u00e2u h\u1ecfi: Em th\u01b0\u1eddng nghe \u0111\u01b0\u1ee3c nh\u1eefng \u00e2m thanh g\u00ec m\u1ed7i ng\u00e0y? \u2013 GV m\u1eddi m\u1ed9t v\u00e0i HS tr\u1ea3 l\u1eddi. \u2013 GV nh\u1eadn x\u00e9t chung v\u00e0 d\u1eabn d\u1eaft v\u00e0o b\u00e0i h\u1ecdc: \u201c\u00c2m thanh trong \u0111\u1eddi s\u1ed1ng\u201d. Ho\u1ea1t \u0111\u1ed9ng 1: T\u00ecm hi\u1ec3u vai tr\u00f2 v\u00e0 \u1ee9ng d\u1ee5ng c\u1ee7a \u00e2m thanh trong \u0111\u1eddi s\u1ed1ng * M\u1ee5c ti\u00eau: HS nh\u1eadn th\u1ee9c \u0111\u01b0\u1ee3c m\u1ed9t s\u1ed1 c\u00f4ng d\u1ee5ng c\u1ee7a \u00e2m thanh trong \u0111\u1eddi s\u1ed1ng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS quan s\u00e1t c\u00e1c h\u00ecnh 1, 2, 3, 4 (SGK, trang 47) v\u00e0 cho bi\u1ebft vai tr\u00f2 c\u1ee7a \u00e2m thanh trong \u0111\u1eddi s\u1ed1ng. \u2013 HS tr\u1ea3 l\u1eddi v\u00e0 nh\u1eadn x\u00e9t l\u1eabn nhau. 74","G\u1ee3i \u00fd: + H\u00ecnh 1: \u00c2m thanh d\u00f9ng khi n\u00f3i chuy\u1ec7n v\u00e0 th\u1ea3o lu\u1eadn v\u1edbi nhau. + H\u00ecnh 2: \u00c2m thanh d\u00f9ng \u0111\u1ec3 gi\u1ea3ng b\u00e0i cho HS. + H\u00ecnh 3: \u00c2m thanh d\u00f9ng trong ca h\u00e1t v\u0103n ngh\u1ec7. + H\u00ecnh 4: \u00c2m thanh d\u00f9ng trong c\u00f2i b\u00e1o hi\u1ec7u c\u1ee7a xe c\u1ee9u th\u01b0\u01a1ng. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: Trong \u0111\u1eddi s\u1ed1ng, \u00e2m thanh \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng khi n\u00f3i chuy\u1ec7n, th\u1ea3o lu\u1eadn, gi\u1ea3ng b\u00e0i, tr\u00ecnh di\u1ec5n v\u0103n ngh\u1ec7, b\u00e1o hi\u1ec7u giao th\u00f4ng (ti\u1ebfng c\u00f2i xe),\u2026 Ho\u1ea1t \u0111\u1ed9ng 2: C\u00f9ng th\u1ea3o lu\u1eadn * M\u1ee5c ti\u00eau: HS tr\u00ecnh b\u00e0y \u0111\u01b0\u1ee3c l\u1ee3i \u00edch c\u1ee7a \u00e2m thanh trong cu\u1ed9c s\u1ed1ng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 4, y\u00eau c\u1ea7u HS th\u1ea3o lu\u1eadn nh\u00f3m v\u00e0 ho\u00e0n th\u00e0nh c\u00e1c nhi\u1ec7m v\u1ee5 sau: + K\u1ec3 m\u1ed9t s\u1ed1 t\u00ecnh hu\u1ed1ng \u00e2m thanh \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong \u0111\u1eddi s\u1ed1ng. + L\u1ea5y m\u1ed9t s\u1ed1 v\u00ed d\u1ee5 \u0111\u1ed9ng v\u1eadt c\u0169ng s\u1eed d\u1ee5ng \u00e2m thanh \u0111\u1ec3 giao ti\u1ebfp. \u2013 GV m\u1eddi \u0111\u1ea1i di\u1ec7n c\u00e1c nh\u00f3m chia s\u1ebb c\u00e2u tr\u1ea3 l\u1eddi. \u2013 GV v\u00e0 HS c\u00f9ng nh\u1eadn x\u00e9t, r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: \u00c2m thanh \u0111\u00f3ng vai tr\u00f2 quan tr\u1ecdng trong \u0111\u1eddi s\u1ed1ng h\u1eb1ng ng\u00e0y nh\u01b0 h\u1ecdc t\u1eadp, giao ti\u1ebfp, th\u01b0\u1edfng th\u1ee9c \u00e2m nh\u1ea1c, b\u00e1o hi\u1ec7u,\u2026 Lo\u00e0i v\u1eadt c\u0169ng s\u1eed d\u1ee5ng \u00e2m thanh \u0111\u1ec3 giao ti\u1ebfp. * Th\u00f4ng tin d\u00e0nh cho GV: Khi \u00e2m thanh \u0111\u01b0\u1ee3c ph\u00e1t ra \u1edf \u0111\u1ed9 cao qu\u00e1 l\u1edbn, tai ng\u01b0\u1eddi kh\u00f4ng nghe \u0111\u01b0\u1ee3c n\u1eefa, \u0111\u00f3 l\u00e0 s\u00f3ng si\u00eau \u00e2m. Tuy v\u1eady, c\u00e1c nh\u00e0 khoa h\u1ecdc t\u00ecm th\u1ea5y b\u1eb1ng ch\u1ee9ng cho th\u1ea5y m\u1ed9t s\u1ed1 con v\u1eadt v\u00e0 c\u00f4n tr\u00f9ng nh\u01b0 c\u00e1 heo, d\u01a1i, b\u01b0\u1edbm \u0111\u00eam,\u2026 c\u00f3 th\u1ec3 c\u1ea3m th\u1ee5 \u0111\u01b0\u1ee3c si\u00eau \u00e2m v\u00e0 nh\u1edd v\u1eady ch\u00fang c\u00f3 th\u1ec3 di chuy\u1ec3n trong b\u00f3ng t\u1ed1i. Tuy kh\u00f4ng nghe \u0111\u01b0\u1ee3c si\u00eau \u00e2m, con ng\u01b0\u1eddi l\u1ea1i c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng lo\u1ea1i \u00e2m thanh n\u00e0y trong nhi\u1ec1u l\u0129nh v\u1ef1c kh\u00e1c nhau. V\u00ed d\u1ee5: s\u1eed d\u1ee5ng si\u00eau \u00e2m trong vi\u1ec7c ch\u1ea9n \u0111o\u00e1n h\u00ecnh \u1ea3nh trong y khoa: si\u00eau \u00e2m tim, si\u00eau \u00e2m \u1ed5 b\u1ee5ng, si\u00eau \u00e2m x\u01b0\u01a1ng, si\u00eau \u00e2m thai,\u2026 Nh\u1edd \u0111\u00f3, b\u00e1c s\u0129 s\u1ebd x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c ch\u00ednh x\u00e1c nguy\u00ean nh\u00e2n g\u00e2y b\u1ec7nh c\u0169ng nh\u01b0 t\u00ecm ra ph\u01b0\u01a1ng ph\u00e1p \u0111i\u1ec1u tr\u1ecb th\u00edch h\u1ee3p cho b\u1ec7nh nh\u00e2n. Ho\u1ea1t \u0111\u1ed9ng 3: T\u00ecm hi\u1ec3u t\u00ean v\u00e0 c\u00e1ch ph\u00e1t ra \u00e2m thanh c\u1ee7a m\u1ed9t s\u1ed1 nh\u1ea1c c\u1ee5 * M\u1ee5c ti\u00eau: HS tr\u00ecnh b\u00e0y \u0111\u01b0\u1ee3c t\u00ean v\u00e0 c\u00e1ch ph\u00e1t ra \u00e2m thanh c\u1ee7a m\u1ed9t s\u1ed1 nh\u1ea1c c\u1ee5. * C\u00e1ch ti\u1ebfn h\u00e0nh: C\u00e1ch 1: \u2013 GV t\u1ed5 ch\u1ee9c cho HS ch\u01a1i tr\u00f2 ch\u01a1i \u201c\u0110o\u00e1n t\u00ean nh\u1ea1c c\u1ee5\u201d. \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 6 v\u00e0 ph\u1ed5 bi\u1ebfn lu\u1eadt ch\u01a1i: M\u1ed7i \u0111\u1ed9i s\u1ebd c\u1eed \u0111\u1ea1i di\u1ec7n l\u00ean nh\u1eadn v\u00e0 ch\u01a1i m\u1ed9t lo\u1ea1i nh\u1ea1c c\u1ee5 (nh\u01b0 tr\u1ed1ng, k\u00e8n, k\u1ebbng tam gi\u00e1c,\u2026) t\u1eeb GV. 75","C\u00e1c nh\u00f3m c\u00f2n l\u1ea1i quay m\u1eb7t \u0111i \u0111\u1ec3 kh\u00f4ng nh\u00ecn th\u1ea5y nh\u1ea1c c\u1ee5 v\u00e0 \u0111o\u00e1n xem \u0111\u00f3 l\u00e0 lo\u1ea1i nh\u1ea1c c\u1ee5 g\u00ec v\u1eeba \u0111\u01b0\u1ee3c ch\u01a1i. N\u00eau c\u00e1ch l\u00e0m \u0111\u1ec3 c\u00e1c nh\u1ea1c c\u1ee5 n\u00e0y ph\u00e1t ra \u00e2m thanh. \u2013 GV t\u1ed5 ch\u1ee9c cho c\u00e1c nh\u00f3m l\u1ea7n l\u01b0\u1ee3t l\u00ean ch\u01a1i. \u2013 GV y\u00eau c\u1ea7u HS: So s\u00e1nh c\u00e1ch l\u00e0m ph\u00e1t ra \u00e2m thanh c\u1ee7a m\u1ed7i nh\u1ea1c c\u1ee5. C\u00e1ch 2: \u2013 GV y\u00eau c\u1ea7u HS quan s\u00e1t c\u00e1c h\u00ecnh 5, 6, 7 (SGK, trang 48) v\u00e0 cho bi\u1ebft: + T\u00ean c\u1ee7a m\u1ed7i nh\u1ea1c c\u1ee5. + C\u00e1ch l\u00e0m \u0111\u1ec3 c\u00e1c nh\u1ea1c c\u1ee5 n\u00e0y ph\u00e1t ra \u00e2m thanh. + So s\u00e1nh c\u00e1ch l\u00e0m ph\u00e1t ra \u00e2m thanh c\u1ee7a m\u1ed7i nh\u1ea1c c\u1ee5. \u2013 GV m\u1eddi 2 \u2013 3 HS chia s\u1ebb c\u00e2u tr\u1ea3 l\u1eddi. \u2013 GV v\u00e0 HS c\u00f9ng nh\u1eadn x\u00e9t, r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: D\u1ef1a v\u00e0o c\u00e1ch l\u00e0m ph\u00e1t ra \u00e2m thanh, ng\u01b0\u1eddi ta ph\u00e2n nh\u1ea1c c\u1ee5 th\u00e0nh c\u00e1c nh\u00f3m nh\u01b0 nh\u1ea1c c\u1ee5 d\u00e2y (\u0111\u00e0n ghi-ta), nh\u1ea1c c\u1ee5 h\u01a1i (s\u00e1o, k\u00e8n), nh\u1ea1c c\u1ee5 g\u00f5 (tr\u1ed1ng, \u0111\u00e0n \u0111\u00e1, c\u1ed3ng, chi\u00eang),\u2026 \u2013 GV y\u00eau c\u1ea7u HS li\u00ean h\u1ec7 th\u1ef1c t\u1ebf \u0111\u1ec3 t\u00ecm t\u00ean m\u1ed9t s\u1ed1 nh\u1ea1c c\u1ee5 v\u00e0 thu th\u1eadp th\u00f4ng tin v\u1ec1 c\u00e1c nh\u1ea1c c\u1ee5 n\u00e0y theo g\u1ee3i \u00fd sau: T\u00ean nh\u1ea1c c\u1ee5 C\u00e1c b\u1ed9 ph\u1eadn ch\u00ednh C\u00e1ch l\u00e0m ph\u00e1t ra \u00e2m thanh Tr\u1ed1ng M\u1eb7t tr\u1ed1ng G\u00f5 ?? ? \u2013 GV t\u1ed5 ch\u1ee9c cho HS chia s\u1ebb v\u1edbi b\u1ea1n k\u1ebft qu\u1ea3 v\u00e0 so s\u00e1nh c\u00e1ch l\u00e0m ph\u00e1t ra \u00e2m thanh c\u1ee7a c\u00e1c nh\u1ea1c c\u1ee5 v\u1eeba t\u00ecm \u0111\u01b0\u1ee3c. G\u1ee3i \u00fd: M\u1ed9t s\u1ed1 nh\u1ea1c c\u1ee5 kh\u00e1c nh\u01b0: tr\u1ed1ng, \u0111\u00e0n d\u01b0\u01a1ng c\u1ea7m (piano), k\u00e8n,\u2026 * Th\u00f4ng tin d\u00e0nh cho GV: Nh\u1ea1c c\u1ee5 c\u1ed5 x\u01b0a nh\u1ea5t c\u1ee7a lo\u00e0i ng\u01b0\u1eddi \u0111\u00e3 c\u00f3 t\u1eeb c\u00e1ch \u0111\u00e2y kho\u1ea3ng n\u0103m m\u01b0\u01a1i ng\u00e0n n\u0103m. C\u00e1c nh\u00e0 kh\u1ea3o c\u1ed5 \u0111\u00e3 t\u00ecm th\u1ea5y nh\u1ea1c c\u1ee5 n\u00e0y l\u00e0 m\u1ed9t c\u00e2y s\u00e1o l\u00e0m t\u1eeb x\u01b0\u01a1ng c\u1ee7a m\u1ed9t con g\u1ea5u s\u1ed1ng trong hang \u0111\u1ed9ng. M\u1ed9t s\u1ed1 nh\u1ea1c c\u1ee5 c\u1ed5 truy\u1ec1n c\u1ee7a ng\u01b0\u1eddi Vi\u1ec7t Nam nh\u01b0 \u0111\u00e0n b\u1ea7u (l\u00e0 lo\u1ea1i \u0111\u00e0n m\u1ed9t d\u00e2y, g\u1ea3y b\u1eb1ng que ho\u1eb7c mi\u1ebfng g\u1ea3y), \u0111\u00e0n \u0111\u00e1 (l\u00e0 nh\u1ea1c c\u1ee5 g\u00f5 c\u1ed5 nh\u1ea5t c\u1ee7a Vi\u1ec7t Nam v\u00e0 l\u00e0 m\u1ed9t trong nh\u1eefng lo\u1ea1i nh\u1ea1c c\u1ee5 c\u1ed5 s\u01a1 nh\u1ea5t c\u1ee7a lo\u00e0i ng\u01b0\u1eddi. \u0110\u00e0n \u0111\u01b0\u1ee3c l\u00e0m b\u1eb1ng c\u00e1c thanh \u0111\u00e1 v\u1edbi k\u00edch th\u01b0\u1edbc d\u00e0i, ng\u1eafn, d\u00e0y, m\u1ecfng kh\u00e1c nhau), \u0111\u00e0n \u0111\u00e1y, tr\u1ed1ng c\u01a1m,\u2026 (Ngu\u1ed3n: https:\/\/vi.wikipedia.org\/wiki\/Nh%E1%BA%A1c_c%E1%BB%A5_ Vi%E1%BB%87t_Nam) 76","Ho\u1ea1t \u0111\u1ed9ng 4: C\u00f9ng s\u00e1ng t\u1ea1o \u201cT\u1ef1 l\u00e0m \u0111\u00e0n\u201d * M\u1ee5c ti\u00eau: HS v\u1eadn d\u1ee5ng ki\u1ebfn th\u1ee9c \u0111\u00e3 h\u1ecdc \u0111\u01b0\u1ee3c \u0111\u1ec3 t\u1ef1 l\u00e0m m\u1ed9t nh\u1ea1c c\u1ee5 \u0111\u00e1nh d\u00e2y \u0111\u01a1n gi\u1ea3n. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 6 v\u00e0 giao nhi\u1ec7m v\u1ee5 cho m\u1ed7i nh\u00f3m: Th\u1ef1c hi\u1ec7n l\u00e0m m\u00f4 h\u00ecnh nh\u01b0 n\u1ed9i dung h\u01b0\u1edbng d\u1eabn \u1edf h\u00ecnh 8 (SGK, trang 48). \u2013 GV quan s\u00e1t v\u00e0 h\u1ed7 tr\u1ee3 c\u00e1c nh\u00f3m khi c\u1ea7n thi\u1ebft. \u2013 GV t\u1ed5 ch\u1ee9c cho HS l\u00ean chia s\u1ebb s\u1ea3n ph\u1ea9m c\u1ee7a nh\u00f3m. \u2013 GV \u0111\u1eb7t th\u00eam c\u00e2u h\u1ecfi cho HS: + Em c\u1ea7n l\u00e0m g\u00ec \u0111\u1ec3 \u0111\u00e0n ph\u00e1t ra \u00e2m thanh? + B\u1ed9 ph\u1eadn n\u00e0o c\u1ee7a \u0111\u00e0n ph\u00e1t ra \u00e2m thanh? + \u00c2m thanh ph\u00e1t ra khi g\u1ea3y t\u1eebng d\u00e2y cao su c\u00f3 kh\u00e1c nhau kh\u00f4ng? G\u1ee3i \u00fd: N\u1ebfu d\u00e2y cao su c\u00f3 b\u1ec1 d\u00e0y kh\u00e1c nhau th\u00ec s\u1ebd ph\u00e1t ra \u00e2m thanh kh\u00e1c nhau khi g\u1ea3y. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 ch\u1ed1t \u00fd: Ch\u00fang ta c\u00f3 th\u1ec3 t\u1ea1o ra nh\u1ea1c c\u1ee5 b\u1eb1ng m\u1ed9t s\u1ed1 v\u1eadt d\u1ee5ng \u0111\u01a1n gi\u1ea3n. Ghi ch\u00fa: GV c\u00f3 th\u1ec3 y\u00eau c\u1ea7u HS t\u1ef1 th\u1ef1c hi\u1ec7n ph\u1ea7n n\u00e0y \u1edf nh\u00e0. \u2013 GV y\u00eau c\u1ea7u HS \u0111\u1ecdc n\u1ed9i dung Em \u0111\u00e3 h\u1ecdc \u0111\u01b0\u1ee3c: \u2022\t \u00c2m thanh \u0111\u00f3ng vai tr\u00f2 quan tr\u1ecdng trong \u0111\u1eddi s\u1ed1ng h\u1eb1ng ng\u00e0y nh\u01b0 h\u1ecdc t\u1eadp, giao ti\u1ebfp, th\u01b0\u1edfng th\u1ee9c \u00e2m nh\u1ea1c, b\u00e1o hi\u1ec7u,\u2026 \u2022\t D\u1ef1a v\u00e0o c\u00e1ch l\u00e0m ph\u00e1t ra \u00e2m thanh, ng\u01b0\u1eddi ta ph\u00e2n nh\u1ea1c c\u1ee5 th\u00e0nh c\u00e1c nh\u00f3m nh\u01b0 nh\u1ea1c c\u1ee5 d\u00e2y (\u0111\u00e0n ghi-ta), nh\u1ea1c c\u1ee5 h\u01a1i (s\u00e1o, k\u00e8n), nh\u1ea1c c\u1ee5 g\u00f5 (tr\u1ed1ng, \u0111\u00e0n \u0111\u00e1, c\u1ed3ng, chi\u00eang),\u2026 Ho\u1ea1t \u0111\u1ed9ng ti\u1ebfp n\u1ed1i sau b\u00e0i h\u1ecdc GV y\u00eau c\u1ea7u HS v\u1ec1 nh\u00e0 t\u00ecm hi\u1ec3u v\u1ec1 m\u1ed9t s\u1ed1 ngu\u1ed3n g\u00e2y \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n \u0111\u1ec3 chu\u1ea9n b\u1ecb cho ti\u1ebft h\u1ecdc ti\u1ebfp theo. Ti\u1ebft 2 Ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng * M\u1ee5c ti\u00eau: T\u1ea1o h\u1ee9ng th\u00fa v\u00e0 kh\u01a1i g\u1ee3i nh\u1eefng hi\u1ec3u bi\u1ebft \u0111\u00e3 c\u00f3 c\u1ee7a HS v\u1ec1 t\u00e1c h\u1ea1i c\u1ee7a \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n v\u00e0 c\u00e1ch ph\u00f2ng ch\u1ed1ng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV \u0111\u1eb7t c\u00e2u h\u1ecfi: Em \u0111\u00e3 t\u1eebng kh\u00f3 ch\u1ecbu v\u00ec nh\u1eefng ti\u1ebfng \u1ed3n xung quanh ch\u01b0a? \u0110\u00f3 l\u00e0 nh\u1eefng ti\u1ebfng \u1ed3n n\u00e0o? \u2013 GV m\u1eddi m\u1ed9t v\u00e0i HS chia s\u1ebb c\u00e2u tr\u1ea3 l\u1eddi. \u2013 GV nh\u1eadn x\u00e9t chung v\u00e0 d\u1eabn d\u1eaft v\u00e0o ti\u1ebft 2 c\u1ee7a b\u00e0i h\u1ecdc. Ho\u1ea1t \u0111\u1ed9ng 1: T\u00ecm hi\u1ec3u nguy\u00ean nh\u00e2n v\u00e0 t\u00e1c h\u1ea1i c\u1ee7a ti\u1ebfng \u1ed3n * M\u1ee5c ti\u00eau: HS tr\u00ecnh b\u00e0y \u0111\u01b0\u1ee3c m\u1ed9t s\u1ed1 ngu\u1ed3n g\u00e2y ra ti\u1ebfng \u1ed3n v\u00e0 nh\u1eefng t\u00e1c h\u1ea1i do ti\u1ebfng \u1ed3n g\u00e2y ra trong \u0111\u1eddi s\u1ed1ng. 77","* C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS l\u00e0m vi\u1ec7c nh\u00f3m \u0111\u00f4i: Quan s\u00e1t c\u00e1c h\u00ecnh 9, 10, 11, 12 (SGK, trang 49), th\u1ea3o lu\u1eadn nh\u00f3m v\u00e0 cho bi\u1ebft nguy\u00ean nh\u00e2n g\u00e2y ra ti\u1ebfng \u1ed3n v\u00e0 nh\u1eefng t\u00e1c h\u1ea1i do ti\u1ebfng \u1ed3n g\u00e2y ra. \u2013 HS chia s\u1ebb c\u00e2u tr\u1ea3 l\u1eddi tr\u01b0\u1edbc l\u1edbp. G\u1ee3i \u00fd: + H\u00ecnh 9: Ti\u1ebfng \u1ed3n do c\u00e1c ph\u01b0\u01a1ng ti\u1ec7n giao th\u00f4ng tr\u00ean \u0111\u01b0\u1eddng ph\u1ed1. + H\u00ecnh 10: Ti\u1ebfng \u1ed3n do c\u00e1c loa c\u00f4ng su\u1ea5t l\u1edbn, v\u00ed d\u1ee5 nh\u01b0 loa c\u1ee7a d\u00e0n karaoke. + H\u00ecnh 11: Ti\u1ebfng \u1ed3n do c\u00e1c s\u00fac v\u1eadt nu\u00f4i. + H\u00ecnh 12: Ti\u1ebfng \u1ed3n do s\u1eeda ch\u1eefa nh\u00e0 c\u1eeda, vi\u1ec7c x\u00e2y d\u1ef1ng c\u00e1c c\u00f4ng tr\u00ecnh trong khu d\u00e2n c\u01b0. \u2013 GV y\u00eau c\u1ea7u HS: K\u1ec3 t\u00ean v\u00e0 n\u00eau t\u00e1c h\u1ea1i c\u1ee7a nh\u1eefng ti\u1ebfng \u1ed3n kh\u00e1c. \u2013 HS tr\u1ea3 l\u1eddi v\u00e0 nh\u1eadn x\u00e9t l\u1eabn nhau. \u2013 GV h\u1ecfi HS: Em v\u00e0 gia \u0111\u00ecnh th\u01b0\u1eddng ph\u1ea3i nghe nh\u1eefng ti\u1ebfng \u1ed3n n\u00e0o? \u2013 HS tr\u1ea3 l\u1eddi. GV nh\u1eadn x\u00e9t v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: Ngu\u1ed3n g\u00e2y ra ti\u1ebfng \u1ed3n trong \u0111\u1eddi s\u1ed1ng th\u01b0\u1eddng l\u00e0: c\u00e1c ph\u01b0\u01a1ng ti\u1ec7n giao th\u00f4ng tr\u00ean \u0111\u01b0\u1eddng ph\u1ed1, loa c\u00f4ng su\u1ea5t l\u1edbn, c\u00e1c s\u00fac v\u1eadt nu\u00f4i, ho\u1ea1t \u0111\u1ed9ng s\u1eeda ch\u1eefa nh\u00e0 c\u1eeda, c\u00f4ng tr\u01b0\u1eddng x\u00e2y d\u1ef1ng. T\u00e1c h\u1ea1i c\u1ee7a nh\u1eefng ti\u1ebfng \u1ed3n n\u00e0y l\u00e0 l\u00e0m m\u1ea5t ng\u1ee7, h\u1ea1i tim m\u1ea1ch, nh\u1ee9c \u0111\u1ea7u,... \u2013 GV t\u1ed5 ch\u1ee9c cho HS \u0111\u1ecdc th\u00f4ng tin \u1edf m\u1ee5c Em t\u00ecm hi\u1ec3u th\u00eam \u0111\u1ec3 HS c\u00f3 th\u00eam ki\u1ebfn th\u1ee9c v\u1ec1 \u0111\u1ed9 to c\u1ee7a \u00e2m thanh v\u00e0 quy chu\u1ea9n v\u1ec1 ti\u1ebfng \u1ed3n. \u2013 GV m\u1eddi HS \u0111\u1ecdc n\u1ed9i dung m\u1ee5c Em t\u00ecm hi\u1ec3u th\u00eam v\u00e0 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: + Ng\u01b0\u1eddi ta \u0111o \u0111\u1ed9 to c\u1ee7a \u00e2m thanh b\u1eb1ng \u0111\u01a1n v\u1ecb g\u00ec? + Ti\u1ebfng n\u00f3i chuy\u1ec7n b\u00ecnh th\u01b0\u1eddng c\u00f3 \u0111\u1ed9 to b\u1eb1ng bao nhi\u00eau \u0111\u1ec1-xi-ben? + \u0110\u1ed9 to c\u1ee7a \u00e2m thanh b\u1eb1ng bao nhi\u00eau th\u00ec \u0111\u01b0\u1ee3c xem nh\u01b0 l\u00e0 ti\u1ebfng \u1ed3n? + Ti\u1ebfp x\u00fac th\u01b0\u1eddng xuy\u00ean v\u1edbi ti\u1ebfng \u1ed3n c\u00f3 th\u1ec3 g\u00e2y nh\u1eefng t\u00e1c h\u1ea1i g\u00ec? * Th\u00f4ng tin d\u00e0nh cho GV: \u0110\u1ed9 to c\u1ee7a \u00e2m thanh \u0111\u01b0\u1ee3c \u0111o b\u1eb1ng \u0111\u01a1n v\u1ecb \u0111\u1ec1-xi-ben (decibel \u2013 dB). \u0110\u1ec3 c\u00f3 kh\u00e1i ni\u1ec7m v\u1ec1 \u0111\u01a1n v\u1ecb dB n\u00e0y, ta c\u00f3 th\u1ec3 n\u00eau v\u00e0i v\u00ed d\u1ee5: 0 dB (ho\u00e0n to\u00e0n kh\u00f4ng nghe), 20 dB (ti\u1ebfng l\u00e1 r\u01a1i), 50 \u2013 60 dB (ti\u1ebfng n\u00f3i chuy\u1ec7n b\u00ecnh th\u01b0\u1eddng), 90 dB (nh\u00e0 m\u00e1y s\u1ea3n xu\u1ea5t),\u2026 Ti\u1ebfng \u1ed3n thu\u1ed9c ph\u1ea1m vi t\u1eeb 76 dB \u0111\u00e3 b\u1eaft \u0111\u1ea7u g\u00e2y kh\u00f3 ch\u1ecbu cho con ng\u01b0\u1eddi v\u00e0 \u0111\u1ed9ng v\u1eadt. Ng\u01b0\u1ee1ng \u00e2m thanh t\u1ed1i \u0111a cho ph\u00e9p con ng\u01b0\u1eddi c\u00f3 th\u1ec3 ch\u1ecbu \u0111\u1ef1ng \u0111\u01b0\u1ee3c l\u00e0 110 dB, n\u1ebfu nh\u01b0 v\u01b0\u1ee3t qua m\u1ee9c n\u00e0y th\u00ec con ng\u01b0\u1eddi c\u00f3 th\u1ec3 b\u1ecb \u0111i\u1ebfc. N\u0103m 2016, B\u1ed9 Y t\u1ebf \u0111\u00e3 ban h\u00e0nh Th\u00f4ng t\u01b0 quy \u0111\u1ecbnh Quy chu\u1ea9n k\u0129 thu\u1eadt qu\u1ed1c gia v\u1ec1 ti\u1ebfng \u1ed3n nh\u01b0 sau: Gi\u1edbi h\u1ea1n cho ph\u00e9p m\u1ee9c \u00e1p su\u1ea5t \u00e2m t\u1ea1i c\u00e1c v\u1ecb tr\u00ed lao \u0111\u1ed9ng: T\u1ea1i v\u1ecb tr\u00ed l\u00e0m vi\u1ec7c, lao \u0111\u1ed9ng, s\u1ea3n xu\u1ea5t tr\u1ef1c ti\u1ebfp: kh\u00f4ng \u0111\u01b0\u1ee3c v\u01b0\u1ee3t qu\u00e1 85 dBA; C\u00e1c ph\u00f2ng ch\u1ee9c n\u0103ng, h\u00e0nh ch\u00ednh, k\u1ebf to\u00e1n, k\u1ebf ho\u1ea1ch: kh\u00f4ng \u0111\u01b0\u1ee3c v\u01b0\u1ee3t qu\u00e1 65 dBA; C\u00e1c ph\u00f2ng lao \u0111\u1ed9ng tr\u00ed \u00f3c, nghi\u00ean c\u1ee9u thi\u1ebft k\u1ebf, th\u1ed1ng k\u00ea, l\u1eadp ch\u01b0\u01a1ng tr\u00ecnh m\u00e1y t\u00ednh, ph\u00f2ng th\u00ed nghi\u1ec7m l\u00ed thuy\u1ebft: kh\u00f4ng \u0111\u01b0\u1ee3c v\u01b0\u1ee3t qu\u00e1 55 dBA.\u00a0 78","Ho\u1ea1t \u0111\u1ed9ng 2: C\u00e1ch gi\u1ea3m \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n v\u00e0 nh\u1eefng n\u01a1i kh\u00f4ng n\u00ean g\u00e2y ti\u1ebfng \u1ed3n * M\u1ee5c ti\u00eau: HS bi\u1ebft \u0111\u01b0\u1ee3c nh\u1eefng c\u00e1ch c\u00f3 th\u1ec3 l\u00e0m gi\u1ea3m ti\u1ebfng \u1ed3n v\u00e0 nh\u1eefng n\u01a1i kh\u00f4ng n\u00ean g\u00e2y ti\u1ebfng \u1ed3n. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS quan s\u00e1t c\u00e1c h\u00ecnh 13 v\u00e0 14 (SGK, trang 50), th\u1ea3o lu\u1eadn nh\u00f3m \u0111\u00f4i v\u00e0 chia s\u1ebb v\u1edbi b\u1ea1n v\u1ec1 c\u00e1ch gi\u1ea3m \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n trong c\u00e1c h\u00ecnh. \u2013 GV t\u1ed5 ch\u1ee9c cho HS l\u00ean chia s\u1ebb c\u00e2u tr\u1ea3 l\u1eddi. G\u1ee3i \u00fd: H\u00ecnh 13: \u0111\u00f3ng k\u00edn c\u1eeda; H\u00ecnh 14: \u0111eo ch\u1ee5p tai. \u2013 GV h\u1ecfi HS: Em c\u00f2n bi\u1ebft nh\u1eefng c\u00e1ch n\u00e0o kh\u00e1c c\u00f3 th\u1ec3 l\u00e0m gi\u1ea3m \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n? \u2013 HS tr\u1ea3 l\u1eddi. GV nh\u1eadn x\u00e9t v\u00e0 g\u1ee3i \u00fd th\u00eam cho HS m\u1ed9t s\u1ed1 c\u00e1ch gi\u00fap gi\u1ea3m \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n nh\u01b0: + X\u00e2y t\u01b0\u1eddng nh\u00e0 c\u00f3 \u0111\u1ed9 d\u00e0y nh\u1ea5t \u0111\u1ecbnh \u0111\u1ec3 gi\u1ea3m ti\u1ebfng \u1ed3n. + L\u1eafp c\u1eeda ch\u1ed1ng \u1ed3n, c\u00e1ch \u00e2m \u0111\u1ec3 h\u1ea1n ch\u1ebf b\u1edbt ti\u1ebfng \u1ed3n. + D\u00e1n t\u01b0\u1eddng b\u1eb1ng x\u1ed1p ch\u1ed1ng \u1ed3n, ti\u00eau \u00e2m. + S\u1eed d\u1ee5ng r\u00e8m c\u1eeda ch\u1ed1ng \u1ed3n. + Tr\u1ed3ng c\u00e2y xanh gi\u1ea3m thi\u1ec3u \u0111\u1ed9 \u1ed3n trong m\u00f4i tr\u01b0\u1eddng. \u2013 GV y\u00eau c\u1ea7u HS ti\u1ebfp t\u1ee5c quan s\u00e1t c\u00e1c h\u00ecnh 15a, 15b, 15c, 15d (SGK, trang 50), th\u1ea3o lu\u1eadn nh\u00f3m \u0111\u00f4i v\u00e0 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: + \u1ede nh\u1eefng n\u01a1i n\u00e0o em kh\u00f4ng n\u00ean g\u00e2y ti\u1ebfng \u1ed3n? V\u00ec sao? + Em l\u00e0m g\u00ec \u0111\u1ec3 tr\u00e1nh g\u00e2y ti\u1ebfng \u1ed3n \u1edf nh\u1eefng n\u01a1i n\u00e0y? \u2013 HS tr\u1ea3 l\u1eddi. GV nh\u1eadn x\u00e9t v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: Nh\u1eefng c\u00e1ch \u0111\u01a1n gi\u1ea3n \u0111\u1ec3 l\u00e0m gi\u1ea3m ti\u1ebfng \u1ed3n: \u0111\u00f3ng c\u1eeda, \u0111eo ch\u1ee5p tai ch\u1ed1ng ti\u1ebfng \u1ed3n. Nh\u1eefng n\u01a1i kh\u00f4ng n\u00ean g\u00e2y ti\u1ebfng \u1ed3n nh\u01b0 b\u1ec7nh vi\u1ec7n, l\u1edbp h\u1ecdc, th\u01b0 vi\u1ec7n, tr\u00ean c\u00e1c ph\u01b0\u01a1ng ti\u1ec7n giao th\u00f4ng c\u00f4ng c\u1ed9ng. Ho\u1ea1t \u0111\u1ed9ng 3: T\u00ecm hi\u1ec3u c\u00e1c ngu\u1ed3n g\u00e2y \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n \u1edf \u0111\u1ecba ph\u01b0\u01a1ng * M\u1ee5c ti\u00eau: HS x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c m\u1ed9t s\u1ed1 ngu\u1ed3n g\u00e2y \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n \u1edf \u0111\u1ecba ph\u01b0\u01a1ng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS th\u1ea3o lu\u1eadn nh\u00f3m 4 \u0111\u1ec3 chia s\u1ebb v\u1ec1 c\u00e1c nguy\u00ean nh\u00e2n g\u00e2y \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n \u1edf \u0111\u1ecba ph\u01b0\u01a1ng. \u2013 GV m\u1eddi \u0111\u1ea1i di\u1ec7n c\u1ee7a 1 \u2013 2 nh\u00f3m l\u00ean chia s\u1ebb tr\u01b0\u1edbc l\u1edbp. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: Nguy\u00ean nh\u00e2n g\u00e2y \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n \u1edf m\u1ed7i \u0111\u1ecba ph\u01b0\u01a1ng kh\u00e1c nhau do tu\u1ef3 thu\u1ed9c v\u00e0o n\u01a1i \u1edf l\u00e0 th\u00e0nh ph\u1ed1 hay n\u00f4ng th\u00f4n, khu d\u00e2n c\u01b0 hay chung c\u01b0, g\u1ea7n hay xa khu c\u00f4ng nghi\u1ec7p, c\u00f4ng tr\u01b0\u1eddng \u0111ang x\u00e2y d\u1ef1ng,\u2026 79","GV y\u00eau c\u1ea7u HS \u0111\u1ecdc n\u1ed9i dung Em \u0111\u00e3 h\u1ecdc \u0111\u01b0\u1ee3c: \u2022\t \u00d4 nhi\u1ec5m ti\u1ebfng \u1ed3n g\u00e2y t\u00e1c h\u1ea1i cho s\u1ee9c kho\u1ebb nh\u01b0 g\u00e2y c\u0103ng th\u1eb3ng v\u00e0 m\u1ec7t m\u1ecfi, \u0111au \u0111\u1ea7u, m\u1ea5t ng\u1ee7, suy nh\u01b0\u1ee3c, gi\u1ea3m th\u00ednh gi\u00e1c,... \u2022\t \u0110\u1ec3 gi\u1ea3m t\u00e1c h\u1ea1i c\u1ee7a ti\u1ebfng \u1ed3n, ch\u00fang ta c\u00f3 th\u1ec3 \u0111\u00f3ng c\u1eeda, mang ch\u1ee5p tai ho\u1eb7c n\u00fat b\u1ecbt tai, di chuy\u1ec3n ra xa ngu\u1ed3n \u00e2m,... \u2022\t M\u1ecdi ng\u01b0\u1eddi c\u1ea7n th\u1ef1c hi\u1ec7n c\u00e1c quy \u0111\u1ecbnh gi\u1eef tr\u1eadt t\u1ef1 n\u01a1i c\u00f4ng c\u1ed9ng v\u00e0 c\u00f3 \u00fd th\u1ee9c kh\u00f4ng g\u00e2y ti\u1ebfng \u1ed3n cho nh\u01b0\u0303ng ng\u01b0\u1eddi xung quanh. GV y\u00eau c\u1ea7u HS \u0111\u1ecdc c\u00e1c t\u1eeb kho\u00e1 c\u1ee7a b\u00e0i: Giao ti\u1ebfp \u2013 Nh\u1ea1c c\u1ee5 \u2013 \u00d4 nhi\u1ec5m ti\u1ebfng \u1ed3n. Ho\u1ea1t \u0111\u1ed9ng ti\u1ebfp n\u1ed1i sau b\u00e0i h\u1ecdc GV y\u00eau c\u1ea7u HS v\u1ec1 nh\u00e0 t\u00ecm hi\u1ec3u v\u1ec1 m\u1ed1i li\u00ean h\u1ec7 gi\u1eefa c\u00e1c kh\u00e1i ni\u1ec7m n\u00f3ng, l\u1ea1nh v\u00e0 nhi\u1ec7t \u0111\u1ed9; d\u1ee5ng c\u1ee5 \u0111o nhi\u1ec7t \u0111\u1ed9 \u0111\u1ec3 chu\u1ea9n b\u1ecb cho b\u00e0i h\u1ecdc sau. B\u00e0i 12. NHI\u1ec6T \u0110\u1ed8 V\u00c0 NHI\u1ec6T K\u1ebe (2 ti\u1ebft) I. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t Sau b\u00e0i h\u1ecdc, HS: \u2013 Tr\u00ecnh b\u00e0y \u0111\u01b0\u1ee3c v\u1eadt n\u00f3ng h\u01a1n th\u00ec c\u00f3 nhi\u1ec7t \u0111\u1ed9 cao h\u01a1n, v\u1eadt l\u1ea1nh h\u01a1n th\u00ec c\u00f3 nhi\u1ec7t \u0111\u1ed9 th\u1ea5p h\u01a1n. \u2013 S\u1eed d\u1ee5ng \u0111\u01b0\u1ee3c nhi\u1ec7t k\u1ebf \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh nhi\u1ec7t \u0111\u1ed9 c\u01a1 th\u1ec3, nhi\u1ec7t \u0111\u1ed9 kh\u00f4ng kh\u00ed. II. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc \u2013 GV: C\u00e1c h\u00ecnh trong b\u00e0i 12 SGK; c\u00e1c lo\u1ea1i nhi\u1ec7t k\u1ebf: nhi\u1ec7t k\u1ebf thu\u1ef7 ng\u00e2n, nhi\u1ec7t k\u1ebf r\u01b0\u1ee3u, nhi\u1ec7t k\u1ebf \u0111i\u1ec7n t\u1eed (hay nhi\u1ec7t k\u1ebf s\u1ed1) v\u00e0 nhi\u1ec7t k\u1ebf h\u1ed3ng ngo\u1ea1i. \u2013 HS: SGK, VBT. III. C\u00c1C Ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc Ti\u1ebft 1 Ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng * M\u1ee5c ti\u00eau: T\u1ea1o h\u1ee9ng th\u00fa v\u00e0 kh\u01a1i g\u1ee3i nh\u1eefng hi\u1ec3u bi\u1ebft \u0111\u00e3 c\u00f3 c\u1ee7a HS v\u1ec1 kh\u00e1i ni\u1ec7m nhi\u1ec7t \u0111\u1ed9. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV \u0111\u1eb7t c\u00e2u h\u1ecfi: Trong \u0111\u1eddi s\u1ed1ng, ch\u00fang ta d\u00f9ng d\u1ee5ng c\u1ee5 g\u00ec \u0111\u1ec3 bi\u1ebft ch\u00ednh x\u00e1c m\u1ed9t v\u1eadt n\u00f3ng h\u01a1n hay l\u1ea1nh h\u01a1n m\u1ed9t v\u1eadt kh\u00e1c? \u2013 GV m\u1eddi 1 \u2013 2 HS tr\u1ea3 l\u1eddi. \u2013 HS tr\u1ea3 l\u1eddi theo kh\u1ea3 n\u0103ng hi\u1ec3u bi\u1ebft c\u1ee7a b\u1ea3n th\u00e2n. \u2013 GV nh\u1eadn x\u00e9t chung v\u00e0 d\u1eabn d\u1eaft v\u00e0o b\u00e0i h\u1ecdc: \u201cNhi\u1ec7t \u0111\u1ed9 v\u00e0 nhi\u1ec7t k\u1ebf\u201d. 80","Ho\u1ea1t \u0111\u1ed9ng 1: T\u00ecm hi\u1ec3u v\u1ec1 n\u00f3ng, l\u1ea1nh v\u00e0 nhi\u1ec7t \u0111\u1ed9 * M\u1ee5c ti\u00eau: HS tr\u00ecnh b\u00e0y \u0111\u01b0\u1ee3c nhi\u1ec7t \u0111\u1ed9 cao h\u01a1n khi v\u1eadt n\u00f3ng h\u01a1n v\u00e0 nhi\u1ec7t \u0111\u1ed9 th\u1ea5p h\u01a1n khi v\u1eadt l\u1ea1nh h\u01a1n. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS quan s\u00e1t c\u00e1c h\u00ecnh 1a, 1b, 2, 3 (SGK, trang 51) v\u00e0 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: + C\u1ed1c n\u01b0\u1edbc trong h\u00ecnh 1a hay c\u1ed1c n\u01b0\u1edbc trong h\u00ecnh 1b c\u00f3 nhi\u1ec7t \u0111\u1ed9 cao h\u01a1n? + B\u1ea3n tin d\u1ef1 b\u00e1o th\u1eddi ti\u1ebft trong h\u00ecnh 2 hay h\u00ecnh 3 cho bi\u1ebft th\u1eddi ti\u1ebft ngo\u00e0i tr\u1eddi n\u00f3ng h\u01a1n? V\u00ec sao em bi\u1ebft? \u2013 GV m\u1eddi 2 \u2013 3 HS tr\u1ea3 l\u1eddi. \u2013 HS tr\u1ea3 l\u1eddi v\u00e0 nh\u1eadn x\u00e9t l\u1eabn nhau. G\u1ee3i \u00fd: + C\u1ed1c n\u01b0\u1edbc trong h\u00ecnh 1a c\u00f3 n\u01b0\u1edbc \u0111\u00e1; c\u1ed1c n\u01b0\u1edbc trong h\u00ecnh 1b c\u00f3 h\u01a1i b\u1ed1c l\u00ean. V\u1eady n\u01b0\u1edbc trong h\u00ecnh 1b n\u00f3ng h\u01a1n. V\u00ec n\u01b0\u1edbc c\u00e0ng n\u00f3ng th\u00ec nhi\u1ec7t \u0111\u1ed9 c\u1ee7a n\u01b0\u1edbc c\u00e0ng cao n\u00ean ta c\u00f3 th\u1ec3 k\u1ebft lu\u1eadn: n\u01b0\u1edbc trong h\u00ecnh 1b c\u00f3 nhi\u1ec7t \u0111\u1ed9 cao h\u01a1n. + B\u1ea3n tin th\u00f4ng b\u00e1o cho bi\u1ebft nhi\u1ec7t \u0111\u1ed9 ngo\u00e0i tr\u1eddi \u1edf h\u00ecnh 2 l\u00e0 36 oC, c\u00f2n \u1edf h\u00ecnh 3 l\u00e0 12 oC n\u00ean ta k\u1ebft lu\u1eadn th\u1eddi ti\u1ebft ngo\u00e0i tr\u1eddi trong h\u00ecnh 2 n\u00f3ng h\u01a1n. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: V\u1eadt ho\u1eb7c kh\u00f4ng kh\u00ed n\u00f3ng h\u01a1n c\u00f3 nhi\u1ec7t \u0111\u1ed9 cao h\u01a1n. V\u1eadt ho\u1eb7c kh\u00f4ng kh\u00ed l\u1ea1nh h\u01a1n c\u00f3 nhi\u1ec7t \u0111\u1ed9 th\u1ea5p h\u01a1n. Ho\u1ea1t \u0111\u1ed9ng 2: C\u00f9ng th\u1ea3o lu\u1eadn * M\u1ee5c ti\u00eau: HS th\u1ea3o lu\u1eadn \u0111\u1ec3 t\u00ecm hi\u1ec3u v\u1ec1 nhi\u1ec7t \u0111\u1ed9 trong m\u1ed9t ng\u00e0y t\u1ea1i \u0111\u1ecba ph\u01b0\u01a1ng em th\u00f4ng qua c\u00e1c ph\u01b0\u01a1ng ti\u1ec7n truy\u1ec1n th\u00f4ng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chia HS th\u00e0nh c\u00e1c nh\u00f3m 6. GV chi\u1ebfu cho HS xem d\u1eef li\u1ec7u th\u1eddi ti\u1ebft t\u1ea1i \u0111\u1ecba ph\u01b0\u01a1ng v\u00e0 m\u1ed9t v\u00e0i t\u1ec9nh kh\u00e1c trong ng\u00e0y (v\u00ed d\u1ee5: Th\u00e0nh ph\u1ed1 H\u1ed3 Ch\u00ed Minh, Ti\u1ec1n Giang, Long An, \u0110\u1ed3ng Th\u00e1p, C\u1ea7n Th\u01a1, B\u1ebfn Tre,\u2026). GV y\u00eau c\u1ea7u HS: + Th\u1ea3o lu\u1eadn nh\u00f3m v\u00e0 n\u00eau nh\u1eadn x\u00e9t v\u1ec1 nhi\u1ec7t \u0111\u1ed9 trong m\u1ed9t ng\u00e0y t\u1ea1i \u0111\u1ecba ph\u01b0\u01a1ng. + So s\u00e1nh nhi\u1ec7t \u0111\u1ed9 trong m\u1ed9t ng\u00e0y t\u1ea1i \u0111\u1ecba ph\u01b0\u01a1ng v\u1edbi t\u1ec9nh kh\u00e1c. \u2013 GV t\u1ed5 ch\u1ee9c cho c\u00e1c nh\u00f3m l\u00ean chia s\u1ebb k\u1ebft qu\u1ea3 th\u1ea3o lu\u1eadn c\u1ee7a nh\u00f3m. \u2013 GV h\u1ecfi th\u00eam HS: Vi\u1ec7c theo d\u00f5i v\u00e0 bi\u1ebft \u0111\u01b0\u1ee3c nhi\u1ec7t \u0111\u1ed9 trong ng\u00e0y c\u00f3 \u00edch l\u1ee3i g\u00ec? \u2013 HS tr\u1ea3 l\u1eddi. GV nh\u1eadn x\u00e9t v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn. G\u1ee3i \u00fd: Ch\u00fang ta c\u1ea7n theo d\u00f5i nhi\u1ec7t \u0111\u1ed9 trong ng\u00e0y \u0111\u1ec3 ch\u1ecdn trang ph\u1ee5c ph\u00f9 h\u1ee3p khi ra ngo\u00e0i. * K\u1ebft lu\u1eadn: Ch\u00fang ta c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng c\u00e1c c\u00e1c ph\u01b0\u01a1ng ti\u1ec7n truy\u1ec1n th\u00f4ng \u0111\u1ec3 bi\u1ebft nhi\u1ec7t \u0111\u1ed9 trong m\u1ed9t ng\u00e0y t\u1ea1i \u0111\u1ecba ph\u01b0\u01a1ng. 81","Ho\u1ea1t \u0111\u1ed9ng 3: T\u00ecm hi\u1ec3u c\u00f4ng d\u1ee5ng c\u1ee7a nhi\u1ec7t k\u1ebf v\u00e0 c\u00e1c lo\u1ea1i nhi\u1ec7t k\u1ebf * M\u1ee5c ti\u00eau: HS bi\u1ebft \u0111\u01b0\u1ee3c c\u00f4ng d\u1ee5ng c\u1ee7a nhi\u1ec7t k\u1ebf v\u00e0 c\u00e1c lo\u1ea1i nhi\u1ec7t k\u1ebf kh\u00e1c nhau. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS \u0111\u1ecdc th\u00f4ng tin v\u00e0 quan s\u00e1t c\u00e1c h\u00ecnh 4, 5, 6 (SGK, trang 52) \u0111\u1ec3 tr\u1ea3 l\u1eddi c\u00e2u h\u1ecfi: C\u00f4ng d\u1ee5ng c\u1ee7a nhi\u1ec7t k\u1ebf l\u00e0 g\u00ec? \u2013 GV c\u00f3 th\u1ec3 \u0111\u1eb7t th\u00eam c\u00e2u h\u1ecfi g\u1ee3i m\u1edf cho HS nh\u01b0: Ch\u00fang ta d\u00f9ng d\u1ee5ng c\u1ee5 g\u00ec \u0111\u1ec3 \u0111o nhi\u1ec7t \u0111\u1ed9 c\u1ee7a ng\u01b0\u1eddi, m\u1ed9t v\u1eadt ho\u1eb7c kh\u00f4ng kh\u00ed? C\u00f3 nh\u1eefng lo\u1ea1i nhi\u1ec7t k\u1ebf n\u00e0o? C\u00f4ng d\u1ee5ng c\u1ee7a m\u1ed7i lo\u1ea1i nhi\u1ec7t k\u1ebf l\u00e0 g\u00ec? \u2013 HS tr\u1ea3 l\u1eddi. GV nh\u1eadn x\u00e9t v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: Nhi\u1ec7t k\u1ebf l\u00e0 d\u1ee5ng c\u1ee5 d\u00f9ng \u0111\u1ec3 \u0111o nhi\u1ec7t \u0111\u1ed9 c\u1ee7a ng\u01b0\u1eddi, m\u1ed9t v\u1eadt hay kh\u00f4ng kh\u00ed. C\u00f3 nhi\u1ec1u lo\u1ea1i nhi\u1ec7t k\u1ebf kh\u00e1c nhau nh\u01b0 nhi\u1ec7t k\u1ebf thu\u1ef7 ng\u00e2n, nhi\u1ec7t k\u1ebf r\u01b0\u1ee3u, nhi\u1ec7t k\u1ebf \u0111i\u1ec7n t\u1eed (hay nhi\u1ec7t k\u1ebf s\u1ed1) v\u00e0 nhi\u1ec7t k\u1ebf h\u1ed3ng ngo\u1ea1i. M\u1ed7i lo\u1ea1i nhi\u1ec7t k\u1ebf \u0111\u01b0\u1ee3c d\u00f9ng tu\u1ef3 theo m\u1ee5c \u0111\u00edch. * Th\u00f4ng tin d\u00e0nh cho GV: Khi \u0111o nhi\u1ec7t \u0111\u1ed9 c\u01a1 th\u1ec3, ng\u01b0\u1eddi ta th\u01b0\u1eddng d\u00f9ng nhi\u1ec7t k\u1ebf thu\u1ef7 ng\u00e2n. Tuy nhi\u00ean, khi \u0111o nhi\u1ec7t \u0111\u1ed9 kh\u00f4ng kh\u00ed (nhi\u1ec7t \u0111\u1ed9 th\u1eddi ti\u1ebft) v\u00e0 nhi\u1ec7t \u0111\u1ed9 n\u01b0\u1edbc th\u00ec nhi\u1ec7t k\u1ebf th\u01b0\u1eddng d\u00f9ng l\u00e0 nhi\u1ec7t k\u1ebf r\u01b0\u1ee3u. Thu\u1ef7 ng\u00e2n ho\u1eb7c r\u01b0\u1ee3u l\u00e0 ch\u1ea5t h\u1ea5p th\u1ee5 nhi\u1ec7t v\u00e0 d\u00e3n n\u1edf n\u00ean khi nhi\u1ec7t \u0111\u1ed9 t\u0103ng hay gi\u1ea3m, m\u1ee9c thu\u1ef7 ng\u00e2n ho\u1eb7c r\u01b0\u1ee3u trong nhi\u1ec7t k\u1ebf s\u1ebd cao l\u00ean ho\u1eb7c th\u1ea5p xu\u1ed1ng so v\u1edbi m\u1ee9c ban \u0111\u1ea7u. Nhi\u1ec7t k\u1ebf r\u01b0\u1ee3u th\u01b0\u1eddng d\u00f9ng \u0111\u1ec3 \u0111o nh\u1eefng nhi\u1ec7t \u0111\u1ed9 th\u1ea5p v\u00ec r\u01b0\u1ee3u ch\u1ec9 \u0111\u00f4ng \u0111\u1eb7c \u1edf nhi\u1ec7t \u0111\u1ed9 th\u1ea5p h\u01a1n \u2013100 oC. Trong khi \u1edf nhi\u1ec7t \u0111\u1ed9 kho\u1ea3ng \u201330 oC, thu\u1ef7 ng\u00e2n \u0111\u00e3 b\u1eaft \u0111\u1ea7u \u0111\u00f4ng \u0111\u1eb7c n\u00ean nhi\u1ec7t k\u1ebf thu\u1ef7 ng\u00e2n ch\u1ec9 d\u00f9ng \u0111\u1ec3 \u0111o nh\u1eefng nhi\u1ec7t \u0111\u1ed9 kh\u00f4ng qu\u00e1 th\u1ea5p. \u0110\u1ec3 \u0111o nhi\u1ec7t \u0111\u1ed9 s\u00f4i v\u00e0 nhi\u1ec7t \u0111\u1ed9 \u0111\u00f4ng \u0111\u1eb7c c\u1ee7a m\u1ed9t ch\u1ea5t, ng\u01b0\u1eddi ta d\u00f9ng nhi\u1ec7t k\u1ebf ph\u00f2ng th\u00ed nghi\u1ec7m. Lo\u1ea1i nhi\u1ec7t k\u1ebf n\u00e0y c\u00f3 th\u1ec3 \u0111o \u0111\u01b0\u1ee3c nhi\u1ec7t \u0111\u1ed9 trong kho\u1ea3ng \u201310 oC \u0111\u1ebfn 110 oC. Nhi\u1ec7t k\u1ebf ph\u00f2ng th\u00ed nghi\u1ec7m c\u00f3 th\u1ec3 l\u00e0 nhi\u1ec7t k\u1ebf thu\u1ef7 ng\u00e2n, nhi\u1ec7t k\u1ebf r\u01b0\u1ee3u, nhi\u1ec7t k\u1ebf b\u1ea3n l\u01b0\u1ee1ng kim (g\u1ed3m hai m\u1ea3nh kim lo\u1ea1i c\u00f3 \u0111\u1ed9 d\u00e3n n\u1edf kh\u00e1c nhau), nhi\u1ec7t k\u1ebf \u0111i\u1ec7n t\u1eed hay nhi\u1ec7t k\u1ebf h\u1ed3ng ngo\u1ea1i. Ho\u1ea1t \u0111\u1ed9ng ti\u1ebfp n\u1ed1i sau b\u00e0i h\u1ecdc GV y\u00eau c\u1ea7u HS v\u1ec1 nh\u00e0 t\u00ecm hi\u1ec3u v\u1ec1 c\u00e1ch s\u1eed d\u1ee5ng nhi\u1ec7t k\u1ebf \u0111\u1ec3 chu\u1ea9n b\u1ecb cho ti\u1ebft h\u1ecdc ti\u1ebfp theo. Ti\u1ebft 2 Ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng * M\u1ee5c ti\u00eau: T\u1ea1o h\u1ee9ng th\u00fa v\u00e0 \u00f4n l\u1ea1i c\u00e1c ki\u1ebfn th\u1ee9c \u0111\u00e3 h\u1ecdc v\u1ec1 nhi\u1ec7t k\u1ebf v\u00e0 c\u00f4ng d\u1ee5ng c\u1ee7a c\u00e1c lo\u1ea1i nhi\u1ec7t k\u1ebf. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS: K\u1ec3 t\u00ean c\u00e1c lo\u1ea1i nhi\u1ec7t k\u1ebf m\u00e0 em \u0111\u00e3 h\u1ecdc v\u00e0 cho bi\u1ebft c\u00f4ng d\u1ee5ng c\u1ee7a ch\u00fang. \u2013 GV m\u1eddi m\u1ed9t v\u00e0i HS tr\u1ea3 l\u1eddi. \u2013 HS tr\u1ea3 l\u1eddi t\u1ef1 do theo kh\u1ea3 n\u0103ng nh\u1edb c\u1ee7a b\u1ea3n th\u00e2n. \u2013 GV nh\u1eadn x\u00e9t chung v\u00e0 d\u1eabn d\u1eaft v\u00e0o ti\u1ebft 2 c\u1ee7a b\u00e0i h\u1ecdc. 82","Ho\u1ea1t \u0111\u1ed9ng 1: Th\u1ef1c h\u00e0nh \u0111o nhi\u1ec7t \u0111\u1ed9 c\u01a1 th\u1ec3 * M\u1ee5c ti\u00eau: HS bi\u1ebft s\u1eed d\u1ee5ng m\u1ed9t s\u1ed1 nhi\u1ec7t k\u1ebf th\u00edch h\u1ee3p \u0111\u1ec3 \u0111o nhi\u1ec7t \u0111\u1ed9 c\u01a1 th\u1ec3. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 4, ph\u00e1t cho m\u1ed7i nh\u00f3m m\u1ed9t s\u1ed1 lo\u1ea1i nhi\u1ec7t k\u1ebf (nhi\u1ec7t k\u1ebf thu\u1ef7 ng\u00e2n, nhi\u1ec7t k\u1ebf \u0111i\u1ec7n t\u1eed, nhi\u1ec7t k\u1ebf h\u1ed3ng ngo\u1ea1i,... tu\u1ef3 \u0111i\u1ec1u ki\u1ec7n c\u1ee7a tr\u01b0\u1eddng, l\u1edbp) v\u00e0 m\u1ed9t phi\u1ebfu h\u1ecdc t\u1eadp c\u00f3 n\u1ed9i dung nh\u01b0 sau: T\u00ean h\u1ecdc sinh Nhi\u1ec7t \u0111\u1ed9 c\u01a1 th\u1ec3 ?? ?? ?? \u2013 GV h\u01b0\u1edbng d\u1eabn HS c\u00e1ch s\u1eed d\u1ee5ng c\u00e1c lo\u1ea1i nhi\u1ec7t k\u1ebf. GV l\u01b0u \u00fd HS: Thu\u1ef7 ng\u00e2n l\u00e0 ch\u1ea5t \u0111\u1ed9c v\u00ec v\u1eady HS kh\u00f4ng \u0111\u01b0\u1ee3c t\u1ef1 \u00fd s\u1eed d\u1ee5ng nhi\u1ec7t k\u1ebf thu\u1ef7 ng\u00e2n \u0111\u1ec3 tr\u00e1nh g\u00e2y nguy hi\u1ec3m cho b\u1ea3n th\u00e2n v\u00e0 b\u1ea1n b\u00e8 xung quanh. \u2013 GV t\u1ed5 ch\u1ee9c cho HS trong m\u1ed7i nh\u00f3m l\u1ea7n l\u01b0\u1ee3t th\u1ef1c h\u00e0nh \u0111o nhi\u1ec7t \u0111\u1ed9 c\u01a1 th\u1ec3 v\u00e0 ghi k\u1ebft qu\u1ea3 v\u00e0o phi\u1ebfu h\u1ecdc t\u1eadp. \u2013 GV y\u00eau c\u1ea7u HS: + So s\u00e1nh k\u1ebft qu\u1ea3 \u0111o \u0111\u01b0\u01a1\u0323c v\u01a1\u0301i nhi\u1ec7t \u0111\u1ed9 trung b\u00ecnh c\u1ee7a c\u01a1 th\u1ec3 ng\u01b0\u1eddi kho\u1ebb m\u1ea1nh l\u00e0 kho\u1ea3ng 37 oC. + Ghi ch\u00fa l\u1ea1i t\u00ean nh\u1eefng b\u1ea1n trong nh\u00f3m c\u00f3 nhi\u1ec7t \u0111\u1ed9 c\u01a1 th\u1ec3 cao h\u01a1n ho\u1eb7c th\u1ea5p h\u01a1n nhi\u1ec7t \u0111\u1ed9 c\u01a1 th\u1ec3 b\u00ecnh th\u01b0\u1eddng l\u00e0 37 oC. + B\u00e1o c\u00e1o k\u1ebft qu\u1ea3 \u0111o \u0111\u01b0\u1ee3c c\u1ee7a nh\u00f3m. \u2013 GV m\u1eddi \u0111\u1ea1i di\u1ec7n c\u00e1c nh\u00f3m l\u00ean b\u00e1o c\u00e1o k\u1ebft qu\u1ea3 th\u1ef1c h\u00e0nh. \u2013 GV nh\u1eadn x\u00e9t, gi\u1ea3i \u0111\u00e1p th\u1eafc m\u1eafc v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: Ch\u00fang ta c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng c\u00e1c lo\u1ea1i nhi\u1ec7t k\u1ebf kh\u00e1c nhau \u0111\u1ec3 \u0111o th\u00e2n nhi\u1ec7t b\u1eb1ng nh\u1eefng c\u00e1ch kh\u00e1c nhau. Nhi\u1ec7t \u0111\u1ed9 trung b\u00ecnh c\u1ee7a c\u01a1 th\u1ec3 ng\u01b0\u1eddi kho\u1ebb m\u1ea1nh l\u00e0 kho\u1ea3ng 37 oC. \u2013 GV \u0111\u1ec1 ngh\u1ecb HS \u0111\u1ecdc ph\u1ea7n C\u1ea3nh b\u00e1o trong SGK: Kh\u00f4ng t\u1ef1 \u00fd s\u1eed d\u1ee5ng nhi\u1ec7t k\u1ebf thu\u1ef7 ng\u00e2n. Thu\u1ef7 ng\u00e2n l\u00e0 ch\u1ea5t \u0111\u1ed9c. Ho\u1ea1t \u0111\u1ed9ng 2: \u0110o nhi\u1ec7t \u0111\u1ed9 c\u1ee7a kh\u00f4ng kh\u00ed trong ph\u00f2ng * M\u1ee5c ti\u00eau: HS th\u1ef1c h\u00e0nh \u0111o nhi\u1ec7t \u0111\u1ed9 c\u1ee7a kh\u00f4ng kh\u00ed trong ph\u00f2ng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 4, ph\u00e1t cho m\u1ed7i nh\u00f3m m\u1ed9t nhi\u1ec7t k\u1ebf r\u01b0\u1ee3u v\u00e0 h\u01b0\u1edbng d\u1eabn HS th\u1ef1c h\u00e0nh: \u0110\u1eb7t nhi\u1ec7t k\u1ebf r\u01b0\u1ee3u l\u00ean m\u1eb7t b\u00e0n \u1edf gi\u1eefa ph\u00f2ng. \u0110\u1ee3i kho\u1ea3ng 3 ph\u00fat v\u00e0 \u0111\u1ecdc k\u1ebft qu\u1ea3 tr\u00ean nhi\u1ec7t k\u1ebf. 83","\u2013 HS c\u00e1c nh\u00f3m th\u1ef1c h\u00e0nh v\u00e0 ghi l\u1ea1i k\u1ebft qu\u1ea3 \u0111o \u0111\u01b0\u1ee3c. \u2013 GV m\u1eddi \u0111\u1ea1i di\u1ec7n t\u1eebng nh\u00f3m b\u00e1o c\u00e1o k\u1ebft qu\u1ea3 th\u1ef1c h\u00e0nh c\u1ee7a nh\u00f3m m\u00ecnh. \u2013 GV c\u00f3 th\u1ec3 t\u1ed5 ch\u1ee9c th\u00eam cho HS th\u1ef1c h\u00e0nh \u0111o nhi\u1ec7t \u0111\u1ed9 c\u1ee7a n\u01b0\u1edbc. GV chu\u1ea9n b\u1ecb cho m\u1ed7i nh\u00f3m hai c\u1ed1c n\u01b0\u1edbc (c\u1ed1c 1 ch\u1ee9a n\u01b0\u1edbc l\u1ea1nh, c\u1ed1c 2 ch\u1ee9a n\u01b0\u1edbc \u1ea5m); m\u1ed9t nhi\u1ec7t k\u1ebf r\u01b0\u1ee3u. GV h\u01b0\u1edbng d\u1eabn HS d\u00f9ng nhi\u1ec7t k\u1ebf r\u01b0\u1ee3u \u0111\u1ec3 \u0111o nhi\u1ec7t \u0111\u1ed9 c\u1ee7a n\u01b0\u1edbc trong m\u1ed7i c\u1ed1c. HS th\u1ef1c h\u00e0nh, ghi l\u1ea1i k\u1ebft qu\u1ea3 \u0111o \u0111\u01b0\u1ee3c v\u00e0 chia s\u1ebb v\u1edbi c\u00e1c b\u1ea1n. \u2013 GV nh\u1eadn x\u00e9t, gi\u1ea3i \u0111\u00e1p th\u1eafc m\u1eafc v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: Ch\u00fang ta c\u00f3 th\u1ec3 \u0111o tr\u1ef1c ti\u1ebfp nhi\u1ec7t \u0111\u1ed9 c\u1ee7a kh\u00f4ng kh\u00ed trong ph\u00f2ng, c\u1ee7a n\u01b0\u1edbc b\u1eb1ng lo\u1ea1i nhi\u1ec7t k\u1ebf ph\u00f9 h\u1ee3p. \u2013 GV y\u00eau c\u1ea7u HS \u0111\u1ecdc n\u1ed9i dung Em \u0111\u00e3 h\u1ecdc \u0111\u01b0\u1ee3c: \u2022\t V\u1eadt ho\u1eb7c kh\u00f4ng kh\u00ed n\u00f3ng h\u01a1n c\u00f3 nhi\u1ec7t \u0111\u1ed9 cao h\u01a1n. V\u1eadt ho\u1eb7c kh\u00f4ng kh\u00ed l\u1ea1nh h\u01a1n c\u00f3 nhi\u1ec7t \u0111\u1ed9 th\u1ea5p h\u01a1n. \u2022\t Nhi\u1ec7t k\u1ebf l\u00e0 d\u1ee5ng c\u1ee5 d\u00f9ng \u0111\u1ec3 \u0111o nhi\u1ec7t \u0111\u1ed9 c\u1ee7a ng\u01b0\u1eddi, m\u1ed9t v\u1eadt hay nhi\u1ec7t \u0111\u1ed9 kh\u00f4ng kh\u00ed. C\u00f3 c\u00e1c lo\u1ea1i nhi\u1ec7t k\u1ebf kh\u00e1c nhau. M\u1ed7i lo\u1ea1i nhi\u1ec7t k\u1ebf \u0111\u01b0\u1ee3c d\u00f9ng tu\u1ef3 theo m\u1ee5c \u0111\u00edch. \u2022\t Nhi\u1ec7t \u0111\u1ed9 trung b\u00ecnh c\u1ee7a c\u01a1 th\u1ec3 ng\u01b0\u1eddi kho\u1ebb m\u1ea1nh l\u00e0 kho\u1ea3ng 37 oC. \u2013 GV d\u1eabn d\u1eaft \u0111\u1ec3 HS n\u00eau \u0111\u01b0\u1ee3c t\u1eeb kho\u00e1 c\u1ee7a b\u00e0i: Nhi\u1ec7t \u0111\u1ed9 \u2013 Nhi\u1ec7t k\u1ebf. Ho\u1ea1t \u0111\u1ed9ng ti\u1ebfp n\u1ed1i sau b\u00e0i h\u1ecdc GV y\u00eau c\u1ea7u HS v\u1ec1 nh\u00e0 t\u00ecm hi\u1ec3u v\u1ec1 s\u1ef1 truy\u1ec1n nhi\u1ec7t v\u00e0 v\u1eadt d\u1eabn nhi\u1ec7t \u0111\u1ec3 chu\u1ea9n b\u1ecb cho b\u00e0i h\u1ecdc sau. B\u00e0i 13. S\u1ef0 TRUY\u1ec0N NHI\u1ec6T V\u00c0 V\u1eacT D\u1eaaN NHI\u1ec6T (2 ti\u1ebft) I. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t Sau b\u00e0i h\u1ecdc, HS: \u2013 V\u1eadn d\u1ee5ng \u0111\u01b0\u1ee3c ki\u1ebfn th\u1ee9c nhi\u1ec7t truy\u1ec1n t\u1eeb v\u1eadt n\u00f3ng h\u01a1n sang v\u1eadt l\u1ea1nh h\u01a1n \u0111\u1ec3 gi\u1ea3i th\u00edch, \u0111\u01b0a ra c\u00e1ch l\u00e0m v\u1eadt n\u00f3ng l\u00ean hay l\u1ea1nh \u0111i trong t\u00ecnh hu\u1ed1ng \u0111\u01a1n gi\u1ea3n. \u2013 \u0110\u1ec1 xu\u1ea5t \u0111\u01b0\u1ee3c c\u00e1ch l\u00e0m th\u00ed nghi\u1ec7m \u0111\u1ec3 t\u00ecm hi\u1ec3u t\u00ednh d\u1eabn nhi\u1ec7t c\u1ee7a v\u1eadt (d\u1eabn nhi\u1ec7t t\u1ed1t hay d\u1eabn nhi\u1ec7t k\u00e9m). \u2013 V\u1eadn d\u1ee5ng \u0111\u01b0\u1ee3c ki\u1ebfn th\u1ee9c v\u1ec1 v\u1eadt d\u1eabn nhi\u1ec7t t\u1ed1t ho\u1eb7c k\u00e9m \u0111\u1ec3 gi\u1ea3i th\u00edch m\u1ed9t s\u1ed1 hi\u1ec7n t\u01b0\u1ee3ng t\u1ef1 nhi\u00ean; \u0111\u1ec3 gi\u1ea3i quy\u1ebft m\u1ed9t s\u1ed1 v\u1ea5n \u0111\u1ec1 \u0111\u01a1n gi\u1ea3n trong cu\u1ed9c s\u1ed1ng. II. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc \u2013 GV: C\u00e1c h\u00ecnh trong b\u00e0i 13 SGK; c\u00e1c v\u1eadt d\u1ee5ng: m\u1ed9t c\u1ed1c n\u01b0\u1edbc n\u00f3ng, m\u1ed9t th\u00eca b\u1eb1ng kim lo\u1ea1i v\u00e0 m\u1ed9t th\u00eca g\u1ed7 c\u00f3 k\u00edch th\u01b0\u1edbc v\u00e0 h\u00ecnh d\u1ea1ng g\u1ea7n nh\u01b0 nhau, hai chai thu\u1ef7 tinh 330 ml, m\u1ed9t s\u1ed1 kh\u0103n gi\u1ea5y ho\u1eb7c v\u1ea3i, b\u0103ng d\u00ednh. \u2013 HS: SGK, VBT. 84","III. C\u00c1C Ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc Ti\u1ebft 1 Ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng * M\u1ee5c ti\u00eau: T\u1ea1o h\u1ee9ng th\u00fa v\u00e0 kh\u01a1i g\u1ee3i nh\u1eefng hi\u1ec3u bi\u1ebft \u0111\u00e3 c\u00f3 c\u1ee7a HS v\u1ec1 s\u1ef1 truy\u1ec1n nhi\u1ec7t. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chi\u1ebfu cho HS xem h\u00ecnh 1 (SGK, trang 53) v\u00e0 y\u00eau c\u1ea7u HS: H\u00e3y d\u1ef1 \u0111o\u00e1n s\u1ef1 thay \u0111\u00f4\u0309i nhi\u1ec7t \u0111\u1ed9 c\u1ee7a c\u1ed1c tra\u0300 n\u00f3ng \u1edf h\u00ecnh 1 sau m\u1ed9t kho\u1ea3ng th\u1eddi gian. \u2013 GV m\u1eddi 2 \u2013 3 HS n\u00eau d\u1ef1 \u0111o\u00e1n. \u2013 GV nh\u1eadn x\u00e9t chung v\u00e0 d\u1eabn d\u1eaft v\u00e0o b\u00e0i h\u1ecdc: \u201cS\u1ef1 truy\u1ec1n nhi\u1ec7t v\u00e0 v\u1eadt d\u1eabn nhi\u1ec7t\u201d. Ho\u1ea1t \u0111\u1ed9ng 1: T\u00ecm hi\u1ec3u s\u1ef1 truy\u1ec1n nhi\u1ec7t * M\u1ee5c ti\u00eau: HS nh\u1eadn th\u1ee9c \u0111\u01b0\u1ee3c nhi\u1ec7t truy\u1ec1n t\u1eeb v\u1eadt n\u00f3ng h\u01a1n sang v\u1eadt l\u1ea1nh h\u01a1n. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 4. GV ph\u00e1t cho m\u1ed7i nh\u00f3m m\u1ed9t b\u00e1t n\u01b0\u1edbc n\u00f3ng v\u00e0 m\u1ed9t th\u00eca kim lo\u1ea1i. GV t\u1ed5 ch\u1ee9c v\u00e0 h\u01b0\u1edbng d\u1eabn cho HS th\u1ef1c hi\u1ec7n th\u00ed nghi\u1ec7m nh\u01b0 sau: + L\u1ea5y tay c\u1ea7m th\u00eca kim lo\u1ea1i. Nh\u1eadn x\u00e9t nhi\u1ec7t \u0111\u1ed9 c\u1ee7a th\u00eca. + \u0110\u1eb7t th\u00eca n\u00e0y v\u00e0o b\u00e1t n\u01b0\u1edbc n\u00f3ng trong v\u00e0i ph\u00fat. Khi ch\u1ea1m tay v\u00e0o th\u00eca, tay em c\u1ea3m th\u1ea5y th\u1ebf n\u00e0o so v\u1edbi khi th\u00eca ch\u01b0a nh\u00fang v\u00e0o n\u01b0\u1edbc? \u2013 HS th\u1ef1c hi\u1ec7n th\u00ed nghi\u1ec7m v\u00e0 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: + Nhi\u1ec7t \u0111\u00e3 truy\u1ec1n t\u1eeb v\u1eadt n\u00e0o sang v\u1eadt n\u00e0o? V\u00ec sao? + Em k\u1ebft lu\u1eadn \u0111\u01b0\u1ee3c g\u00ec v\u1ec1 chi\u1ec1u truy\u1ec1n nhi\u1ec7t gi\u1eefa v\u1eadt n\u00f3ng v\u00e0 v\u1eadt l\u1ea1nh? \u2013 GV m\u1eddi HS tr\u1ea3 l\u1eddi v\u00e0 nh\u1eadn x\u00e9t l\u1eabn nhau. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: Nhi\u1ec7t \u0111\u01b0\u1ee3c truy\u1ec1n t\u1eeb v\u1eadt n\u00f3ng h\u01a1n sang v\u1eadt l\u1ea1nh h\u01a1n. Sau m\u1ed9t th\u1eddi gian, khi hai v\u1eadt c\u00f3 c\u00f9ng nhi\u1ec7t \u0111\u1ed9, s\u1ebd kh\u00f4ng c\u00f2n s\u1ef1 truy\u1ec1n nhi\u1ec7t. Ho\u1ea1t \u0111\u1ed9ng 2: C\u00f9ng th\u1ea3o lu\u1eadn * M\u1ee5c ti\u00eau: HS v\u1eadn d\u1ee5ng ki\u1ebfn th\u1ee9c v\u1ec1 s\u1ef1 truy\u1ec1n nhi\u1ec7t \u0111\u1ec3 gi\u1ea3i th\u00edch t\u00ecnh hu\u1ed1ng th\u1ef1c t\u1ebf trong \u0111\u1eddi s\u1ed1ng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS quan s\u00e1t h\u00ecnh 3 (SGK, trang 53), th\u1ea3o lu\u1eadn nh\u00f3m \u0111\u00f4i \u0111\u1ec3 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi sau: + V\u00ec sao b\u00e0n tay em l\u1ea1nh khi \u00e1p v\u00e0o c\u1ed1c n\u01b0\u1edbc \u0111\u00e1 l\u1ea1nh? + Nhi\u1ec7t \u0111\u01b0\u1ee3c truy\u1ec1n t\u1eeb v\u1eadt n\u00e0o \u0111\u1ebfn v\u1eadt n\u00e0o? 85","\u2013 GV m\u1eddi \u0111\u1ea1i di\u1ec7n c\u00e1c nh\u00f3m tr\u1ea3 l\u1eddi. \u2013 GV v\u00e0 HS nh\u1eadn x\u00e9t, r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: Nhi\u1ec7t s\u1ebd truy\u1ec1n t\u1eeb b\u00e0n tay sang c\u1ed1c n\u01b0\u1edbc n\u00ean tay l\u1ea1nh \u0111i. Nhi\u1ec7t truy\u1ec1n t\u1eeb tay (c\u00f3 nhi\u1ec7t \u0111\u1ed9 n\u00f3ng h\u01a1n) sang c\u1ed1c n\u01b0\u1edbc l\u1ea1nh (c\u00f3 nhi\u1ec7t \u0111\u1ed9 l\u1ea1nh h\u01a1n). Ho\u1ea1t \u0111\u1ed9ng 3: T\u00ecm hi\u1ec3u v\u1eadt d\u1eabn nhi\u1ec7t t\u1ed1t v\u00e0 v\u1eadt d\u1eabn nhi\u1ec7t k\u00e9m * M\u1ee5c ti\u00eau: HS nh\u1eadn bi\u1ebft \u0111\u01b0\u1ee3c v\u1eadt d\u1eabn nhi\u1ec7t t\u1ed1t v\u00e0 v\u1eadt d\u1eabn nhi\u1ec7t k\u00e9m h\u01a1n qua th\u00ed nghi\u1ec7m. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS \u0111\u1ec1 xu\u1ea5t th\u00ed nghi\u1ec7m v\u1edbi m\u1ed9t th\u00eca b\u1eb1ng kim lo\u1ea1i (nh\u01b0 s\u1eaft), m\u1ed9t th\u00eca b\u1eb1ng g\u1ed7 c\u00f3 k\u00edch th\u01b0\u1edbc v\u00e0 h\u00ecnh d\u1ea1ng g\u1ea7n gi\u1ed1ng nhau \u0111\u1ec3 bi\u1ebft th\u00eca n\u00e0o d\u1eabn nhi\u1ec7t t\u1ed1t h\u01a1n, th\u00eca n\u00e0o d\u1eabn nhi\u1ec7t k\u00e9m h\u01a1n. \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 4, ph\u00e1t cho m\u1ed7i nh\u00f3m: m\u1ed9t c\u1ed1c n\u01b0\u1edbc n\u00f3ng, m\u1ed9t th\u00eca g\u1ed7, m\u1ed9t th\u00eca kim lo\u1ea1i c\u00f3 k\u00edch th\u01b0\u1edbc v\u00e0 h\u00ecnh d\u1ea1ng g\u1ea7n gi\u1ed1ng nhau. GV t\u1ed5 ch\u1ee9c v\u00e0 h\u01b0\u1edbng d\u1eabn cho HS th\u1ef1c hi\u1ec7n th\u00ed nghi\u1ec7m nh\u01b0 sau: + Nh\u00fang hai th\u00eca v\u00e0o c\u1ed1c n\u01b0\u1edbc. \u0110\u1ee3i kho\u1ea3ng 2 \u2013 3 ph\u00fat. + Ch\u1ea1m nh\u1eb9 tay v\u00e0o m\u1ed7i th\u00eca. \u2013 HS th\u1ef1c hi\u1ec7n th\u00ed nghi\u1ec7m v\u00e0 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: + Em th\u1ea5y th\u00eca n\u00e0o n\u00f3ng h\u01a1n? + Em r\u00fat ra k\u1ebft lu\u1eadn g\u00ec v\u1ec1 t\u00ednh d\u1eabn nhi\u1ec7t c\u1ee7a g\u1ed7 v\u00e0 c\u1ee7a kim lo\u1ea1i (nh\u01b0 s\u1eaft)? \u2013 GV m\u1eddi HS tr\u1ea3 l\u1eddi v\u00e0 nh\u1eadn x\u00e9t l\u1eabn nhau. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: S\u1eaft l\u00e0 v\u1eadt li\u1ec7u d\u1eabn nhi\u1ec7t t\u1ed1t. G\u1ed7 d\u1eabn nhi\u1ec7t r\u1ea5t k\u00e9m (h\u1ea7u nh\u01b0 kh\u00f4ng d\u1eabn nhi\u1ec7t). Ho\u1ea1t \u0111\u1ed9ng 4: Nh\u1eadn bi\u1ebft m\u1ed9t s\u1ed1 v\u1eadt d\u1ee5ng d\u1eabn nhi\u1ec7t t\u1ed1t v\u00e0 v\u1eadt d\u1ee5ng d\u1eabn nhi\u1ec7t k\u00e9m trong \u0111\u1eddi s\u1ed1ng * M\u1ee5c ti\u00eau: HS nh\u1eadn bi\u1ebft \u0111\u01b0\u1ee3c m\u1ed9t s\u1ed1 v\u1eadt d\u1ee5ng d\u1eabn nhi\u1ec7t t\u1ed1t v\u00e0 v\u1eadt d\u1ee5ng d\u1eabn nhi\u1ec7t k\u00e9m trong \u0111\u1eddi s\u1ed1ng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV t\u1ed5 ch\u1ee9c cho HS quan s\u00e1t h\u00ecnh 5 (SGK, trang 54), th\u1ea3o lu\u1eadn theo nh\u00f3m 4 v\u00e0 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi sau: + C\u00e1c d\u1ee5ng c\u1ee5 \u0111un n\u1ea5u trong b\u1ebfp th\u01b0\u1eddng l\u00e0m b\u1eb1ng g\u00ec? Tay c\u1ea7m c\u1ee7a c\u00e1c d\u1ee5ng c\u1ee5 n\u00e0y th\u01b0\u1eddng l\u00e0m b\u1eb1ng g\u00ec? Gi\u1ea3i th\u00edch. + Ch\u00fang ta th\u01b0\u1eddng m\u1eb7c trang ph\u1ee5c l\u00e0m b\u1eb1ng ch\u1ea5t li\u1ec7u g\u00ec \u0111\u1ec3 gi\u1eef \u1ea5m c\u01a1 th\u1ec3 khi th\u1eddi ti\u1ebft l\u1ea1nh? V\u00ec sao? \u2013 GV m\u1eddi \u0111\u1ea1i di\u1ec7n c\u00e1c nh\u00f3m chia s\u1ebb c\u00e2u tr\u1ea3 l\u1eddi. \u2013 GV y\u00eau c\u1ea7u HS: K\u1ec3 t\u00ean nh\u1eefng v\u1eadt d\u1ee5ng gi\u00fap gi\u1eef cho n\u01b0\u1edbc \u0111\u01b0\u1ee3c n\u00f3ng l\u00e2u trong gia \u0111\u00ecnh em. T\u00ecm hi\u1ec3u v\u1ec1 c\u00e1ch gi\u1eef nhi\u1ec7t c\u1ee7a c\u00e1c v\u1eadt d\u1ee5ng \u0111\u00f3. \u2013 HS chia s\u1ebb c\u00e2u tr\u1ea3 l\u1eddi. GV nh\u1eadn x\u00e9t v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn. 86","* K\u1ebft lu\u1eadn: Nh\u1eefng v\u1eadt b\u1eb1ng kim lo\u1ea1i nh\u01b0 s\u1eaft, \u0111\u1ed3ng,... d\u1eabn nhi\u1ec7t t\u1ed1t. Nh\u1eefng v\u1eadt b\u1eb1ng v\u1ea3i, g\u1ed7, thu\u1ef7 tinh,... d\u1eabn nhi\u1ec7t k\u00e9m. Ch\u00fang ta ch\u1ecdn v\u1eadt li\u1ec7u d\u1eabn nhi\u1ec7t t\u1ed1t ho\u1eb7c d\u1eabn nhi\u1ec7t k\u00e9m \u0111\u1ec3 l\u00e0m c\u00e1c v\u1eadt d\u1ee5ng tu\u1ef3 theo nhu c\u1ea7u c\u1ea7n s\u1eed d\u1ee5ng trong \u0111\u1eddi s\u1ed1ng. * Th\u00f4ng tin d\u00e0nh cho GV: 1. Hi\u1ec7n t\u01b0\u1ee3ng truy\u1ec1n nhi\u1ec7t: M\u1ed9t c\u00e1ch t\u1ed5ng qu\u00e1t, hi\u1ec7n t\u01b0\u1ee3ng truy\u1ec1n nhi\u1ec7t (hay trao \u0111\u1ed5i nhi\u1ec7t gi\u1eefa hai hay nhi\u1ec1u v\u1eadt) \u0111\u01b0\u1ee3c ph\u00e2n l\u00e0m 3 h\u00ecnh th\u1ee9c kh\u00e1c nhau, tu\u1ef3 theo c\u01a1 ch\u1ebf. \u0110\u00f3 l\u00e0 hi\u1ec7n t\u01b0\u1ee3ng d\u1eabn nhi\u1ec7t, hi\u1ec7n t\u01b0\u1ee3ng \u0111\u1ed1i l\u01b0u nhi\u1ec7t v\u00e0 hi\u1ec7n t\u01b0\u1ee3ng b\u1ee9c x\u1ea1 nhi\u1ec7t. \u2022\t Hi\u1ec7n t\u01b0\u1ee3ng d\u1eabn nhi\u1ec7t: L\u00e0 hi\u1ec7n t\u01b0\u1ee3ng m\u00e0 HS \u0111\u01b0\u1ee3c h\u1ecdc trong b\u00e0i n\u00e0y c\u1ee7a ch\u01b0\u01a1ng tr\u00ecnh Khoa h\u1ecdc l\u1edbp 4. Hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y x\u1ea3y ra trong m\u1ed9t v\u1eadt t\u1eeb v\u00f9ng c\u00f3 nhi\u1ec7t \u0111\u1ed9 cao sang v\u00f9ng c\u00f3 nhi\u1ec7t \u0111\u1ed9 th\u1ea5p h\u01a1n ho\u1eb7c gi\u1eefa hai v\u1eadt ti\u1ebfp x\u00fac c\u00f3 nhi\u1ec7t \u0111\u1ed9 kh\u00e1c nhau. V\u00ed d\u1ee5 nh\u01b0 khi \u00e1p b\u00e0n tay v\u00e0o m\u1ed9t c\u1ed1c n\u01b0\u1edbc l\u1ea1nh, nhi\u1ec7t s\u1ebd truy\u1ec1n t\u1eeb b\u00e0n tay sang c\u1ed1c n\u01b0\u1edbc cho \u0111\u1ebfn khi b\u00e0n tay v\u00e0 c\u1ed1c n\u01b0\u1edbc c\u00f3 c\u00f9ng nhi\u1ec7t \u0111\u1ed9 th\u00ec s\u1ef1 truy\u1ec1n nhi\u1ec7t s\u1ebd d\u1eebng l\u1ea1i. \u2022\t Hi\u1ec7n t\u01b0\u1ee3ng \u0111\u1ed1i l\u01b0u nhi\u1ec7t: L\u00e0 s\u1ef1 truy\u1ec1n n\u0103ng l\u01b0\u1ee3ng nhi\u1ec7t nh\u1edd s\u1ef1 chuy\u1ec3n \u0111\u1ed9ng c\u1ee7a c\u00e1c d\u00f2ng ch\u1ea5t l\u1ecfng hay ch\u1ea5t kh\u00ed gi\u1eefa c\u00e1c v\u00f9ng c\u00f3 nhi\u1ec7t \u0111\u1ed9 kh\u00e1c nhau. V\u00ed d\u1ee5: Khi l\u00f2 s\u01b0\u1edfi ho\u1ea1t \u0111\u1ed9ng, kh\u00f4ng kh\u00ed quanh l\u00f2 s\u01b0\u1edfi \u0111\u01b0\u1ee3c s\u01b0\u1edfi n\u00f3ng s\u1ebd lan to\u1ea3 trong kh\u00f4ng gian xung quanh. \u2022\t Hi\u1ec7n t\u01b0\u1ee3ng b\u1ee9c x\u1ea1 nhi\u1ec7t: Nhi\u1ec7t \u0111\u01b0\u1ee3c truy\u1ec1n \u0111i nh\u1edd s\u00f3ng \u0111i\u1ec7n t\u1eeb nh\u01b0 \u00e1nh s\u00e1ng. \u0110\u1eb7c \u0111i\u1ec3m c\u1ee7a c\u01a1 ch\u1ebf truy\u1ec1n nhi\u1ec7t n\u00e0y l\u00e0 nhi\u1ec7t c\u00f3 th\u1ec3 truy\u1ec1n \u0111i trong ch\u00e2n kh\u00f4ng m\u00e0 kh\u00f4ng c\u1ea7n m\u1ed9t m\u00f4i tr\u01b0\u1eddng trung gian nh\u01b0 trong hi\u1ec7n t\u01b0\u1ee3ng \u0111\u1ed1i l\u01b0u nhi\u1ec7t. V\u00ed d\u1ee5 th\u00f4ng d\u1ee5ng nh\u1ea5t c\u1ee7a hi\u1ec7n t\u01b0\u1ee3ng b\u1ee9c x\u1ea1 nhi\u1ec7t l\u00e0 s\u1ef1 truy\u1ec1n nhi\u1ec7t b\u1edfi \u00e1nh s\u00e1ng, v\u00ed d\u1ee5: \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi. 2. \u0110\u1ed9 d\u1eabn nhi\u1ec7t c\u1ee7a m\u1ed9t s\u1ed1 v\u1eadt li\u1ec7u: + V\u1eadt d\u1eabn nhi\u1ec7t t\u1ed1t hay k\u00e9m \u0111\u01b0\u1ee3c \u0111\u00e1nh gi\u00e1 b\u1edfi m\u1ed9t \u0111\u1ea1i l\u01b0\u1ee3ng g\u1ecdi l\u00e0 h\u1ec7 s\u1ed1 d\u1eabn nhi\u1ec7t, \u0111\u01b0\u1ee3c hi\u1ec3u l\u00e0 l\u01b0\u1ee3ng nhi\u1ec7t \u0111\u01b0\u1ee3c truy\u1ec1n \u0111i qua m\u1ed9t di\u1ec7n t\u00edch b\u1eb1ng 1 m2 trong th\u1eddi gian b\u1eb1ng 1 gi\u00e2y. + M\u1ed9t s\u1ed1 v\u00ed d\u1ee5 v\u1ec1 h\u1ec7 s\u1ed1 d\u1eabn nhi\u1ec7t: V\u1eadt li\u1ec7u \u0110\u1ed9 d\u1eabn nhi\u1ec7t (W.m\u20131.K\u20131) B\u1ea1c 406 Nh\u00f4m 205 B\u00ea t\u00f4ng 2,1 G\u1ed7 0,15 Kh\u00f4ng kh\u00ed 0,024 Theo b\u1ea3ng tr\u00ean, ta th\u1ea5y g\u1ed7 d\u1eabn nhi\u1ec7t kh\u00e1 k\u00e9m n\u00ean trong x\u00e2y d\u1ef1ng ng\u01b0\u1eddi ta th\u01b0\u1eddng d\u00f9ng g\u1ed7 \u0111\u1ec3 l\u00f3t t\u01b0\u1eddng v\u00e0 n\u1ec1n nh\u00e0 nh\u1eb1m m\u1ee5c \u0111\u00edch ng\u0103n c\u1ea3n nhi\u1ec7t truy\u1ec1n v\u00e0o trong ph\u00f2ng khi trong ph\u00f2ng m\u1edf m\u00e1y \u0111i\u1ec1u ho\u00e0 v\u00e0 ng\u0103n nhi\u1ec7t truy\u1ec1n ra ngo\u00e0i khi c\u0103n ph\u00f2ng \u0111\u01b0\u1ee3c s\u01b0\u1edfi \u1ea5m. (Ngu\u1ed3n: https:\/\/vi.wikipedia.org\/wiki\/%C4%90%E1%BB%99_d%E1%BA%ABn_ nhi%E1%BB%87t) 87","\u2013 GV y\u00eau c\u1ea7u HS \u0111\u1ecdc n\u1ed9i dung Em \u0111\u00e3 h\u1ecdc \u0111\u01b0\u1ee3c: \u2022\t Khi hai v\u1eadt c\u00f3 nhi\u1ec7t \u0111\u1ed9 kh\u00e1c nhau ti\u1ebfp xu\u0301c v\u1edbi nhau th\u00ec nhi\u1ec7t \u0111\u01b0\u1ee3c truy\u1ec1n t\u1eeb v\u1eadt n\u00f3ng h\u01a1n sang v\u1eadt l\u1ea1nh h\u01a1n. \u2022\t Nh\u1eefng v\u1eadt b\u1eb1ng kim lo\u1ea1i nh\u01b0 s\u0103\u0301t, \u0111\u1ed3ng,... d\u1eabn nhi\u1ec7t t\u1ed1t. Nh\u1eefng v\u1eadt b\u1eb1ng v\u1ea3i, g\u1ed7, thu\u1ef7 tinh,\u2026 d\u1eabn nhi\u1ec7t k\u00e9m. Ho\u1ea1t \u0111\u1ed9ng ti\u1ebfp n\u1ed1i sau b\u00e0i h\u1ecdc GV y\u00eau c\u1ea7u HS v\u1ec1 nh\u00e0 t\u00ecm hi\u1ec3u c\u00f4ng d\u1ee5ng v\u00e0 c\u1ea5u t\u1ea1o c\u1ee7a b\u00ecnh gi\u1eef nhi\u1ec7t \u0111\u1ec3 chu\u1ea9n b\u1ecb cho ti\u1ebft 2. Ti\u1ebft 2 Ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng * M\u1ee5c ti\u00eau: T\u1ea1o h\u1ee9ng th\u00fa v\u00e0 \u00f4n l\u1ea1i c\u00e1c ki\u1ebfn th\u1ee9c v\u1ec1 v\u1eadt d\u1eabn nhi\u1ec7t t\u1ed1t v\u00e0 v\u1eadt d\u1eabn nhi\u1ec7t k\u00e9m. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS: H\u00e3y k\u1ec3 t\u00ean m\u1ed9t s\u1ed1 v\u1eadt d\u1eabn nhi\u1ec7t t\u1ed1t, m\u1ed9t s\u1ed1 v\u1eadt d\u1eabn nhi\u1ec7t k\u00e9m m\u00e0 em bi\u1ebft. \u2013 HS thi \u0111ua tr\u1ea3 l\u1eddi. \u2013 GV nh\u1eadn x\u00e9t chung v\u00e0 d\u1eabn d\u1eaft HS v\u00e0o ti\u1ebft 2 c\u1ee7a b\u00e0i h\u1ecdc. Ho\u1ea1t \u0111\u1ed9ng 1: C\u00f9ng th\u1ea3o lu\u1eadn * M\u1ee5c ti\u00eau: HS v\u1eadn d\u1ee5ng ki\u1ebfn th\u1ee9c v\u1ec1 s\u1ef1 truy\u1ec1n nhi\u1ec7t, v\u1eadt d\u1eabn nhi\u1ec7t t\u1ed1t v\u00e0 v\u1eadt d\u1eabn nhi\u1ec7t k\u00e9m \u0111\u1ec3 gi\u1ea3i th\u00edch m\u1ed9t t\u00ecnh hu\u1ed1ng th\u1ef1c t\u1ebf trong \u0111\u1eddi s\u1ed1ng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS quan s\u00e1t h\u00ecnh 6 (SGK, trang 55), th\u1ea3o lu\u1eadn nh\u00f3m 4 \u0111\u1ec3 tr\u1ea3 l\u1eddi c\u00e2u h\u1ecfi: V\u00ec sao v\u00e0o ban ng\u00e0y, nh\u1eefng l\u00fac c\u00f3 M\u1eb7t Tr\u1eddi, c\u00e1t \u1edf b\u00e3i bi\u1ec3n c\u00f3 khi tr\u1edf n\u00ean r\u1ea5t n\u00f3ng v\u00e0 ta n\u00ean mang gi\u00e0y, d\u00e9p \u0111\u1ec3 tr\u00e1nh b\u1ecb b\u1ecfng ch\u00e2n? \u2013 GV m\u1eddi \u0111\u1ea1i di\u1ec7n c\u00e1c nh\u00f3m chia s\u1ebb c\u00e2u tr\u1ea3 l\u1eddi. C\u00e1c HS kh\u00e1c nh\u1eadn x\u00e9t v\u00e0 b\u1ed5 sung. G\u1ee3i \u00fd: Nhi\u1ec7t \u0111\u1ed9 t\u1eeb \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi truy\u1ec1n \u0111\u1ebfn c\u00e1t n\u00ean c\u00e1t \u1edf b\u00e3i bi\u1ec3n s\u1ebd n\u00f3ng l\u00ean khi c\u00f3 \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi. Gi\u00e0y, d\u00e9p \u0111\u01b0\u1ee3c l\u00e0m t\u1eeb c\u00e1c v\u1eadt li\u1ec7u d\u1eabn nhi\u1ec7t k\u00e9m (h\u1ea7u nh\u01b0 kh\u00f4ng d\u1eabn nhi\u1ec7t) n\u00ean s\u1ebd gi\u00fap b\u1ea3o v\u1ec7 ch\u00e2n kh\u00f4ng b\u1ecb b\u1ecfng khi \u0111i tr\u00ean c\u00e1t n\u00f3ng. \u2013 GV l\u1ed3ng gh\u00e9p gi\u00e1o d\u1ee5c th\u00eam k\u0129 n\u0103ng s\u1ed1ng cho HS: Ch\u00fang ta ph\u1ea3i c\u1ea9n th\u1eadn khi ti\u1ebfp x\u00fac g\u1ea7n v\u1edbi c\u00e1c ngu\u1ed3n nhi\u1ec7t \u0111ang n\u00f3ng, c\u1ea7n c\u00f3 bi\u1ec7n ph\u00e1p an to\u00e0n khi ti\u1ebfp x\u00fac \u0111\u1ec3 tr\u00e1nh g\u00e2y nguy hi\u1ec3m cho b\u1ea3n th\u00e2n. V\u00ed d\u1ee5: d\u00f9ng \u0111\u0129a \u0111\u1ec3 k\u00ea l\u00f3t khi b\u00ea b\u00e1t canh n\u00f3ng hay c\u1ed1c n\u01b0\u1edbc n\u00f3ng; \u0111i gi\u00e0y, d\u00e9p khi ph\u1ea3i \u0111i b\u1ed9 tr\u00ean m\u1eb7t \u0111\u01b0\u1eddng nh\u1ef1a v\u00e0o l\u00fac tr\u1eddi n\u1eafng; d\u00f9ng mi\u1ebfng v\u1ea3i l\u00f3t \u0111\u1ec3 nh\u1ea5c n\u1ed3i khi \u0111un n\u1ea5u,\u2026 \u2013 GV h\u01b0\u1edbng d\u1eabn HS c\u00f9ng r\u00fat ra k\u1ebft lu\u1eadn.\t * K\u1ebft lu\u1eadn: D\u1ef1a v\u00e0o t\u00ednh ch\u1ea5t d\u1eabn nhi\u1ec7t t\u1ed1t v\u00e0 k\u00e9m c\u1ee7a c\u00e1c v\u1eadt li\u1ec7u, con ng\u01b0\u1eddi \u0111\u00e3 \u1ee9ng d\u1ee5ng \u0111\u1ec3 ch\u1ebf t\u1ea1o c\u00e1c d\u1ee5ng c\u1ee5, \u0111\u1ed3 d\u00f9ng h\u1eefu \u00edch, ph\u1ee5c v\u1ee5 cho \u0111\u1eddi s\u1ed1ng h\u1eb1ng n\u00e0y. 88","Ho\u1ea1t \u0111\u1ed9ng 2: C\u00f9ng s\u00e1ng t\u1ea1o \u201cT\u1ef1 l\u00e0m b\u00ecnh gi\u1eef nhi\u1ec7t\u201d * M\u1ee5c ti\u00eau: HS v\u1eadn d\u1ee5ng ki\u1ebfn th\u1ee9c \u0111\u00e3 h\u1ecdc v\u1ec1 s\u1ef1 truy\u1ec1n nhi\u1ec7t v\u00e0 v\u1eadt d\u1eabn nhi\u1ec7t \u0111\u1ec3 t\u1ef1 l\u00e0m b\u00ecnh gi\u1eef nhi\u1ec7t. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 6, y\u00eau c\u1ea7u m\u1ed7i nh\u00f3m ki\u1ec3m tra l\u1ea1i c\u00e1c v\u1eadt d\u1ee5ng \u0111\u00e3 chu\u1ea9n b\u1ecb: hai chai thuy\u0309 tinh 330 ml, m\u1ed9t s\u1ed1 kh\u0103n gi\u1ea5y ho\u1eb7c v\u1ea3i, b\u0103ng d\u00ednh. \u2013 GV h\u01b0\u1edbng d\u1eabn c\u00e1c nh\u00f3m th\u1ef1c h\u00e0nh l\u00e0m b\u00ecnh gi\u1eef nhi\u1ec7t theo c\u00e1c b\u01b0\u1edbc sau: + M\u1ed9t chai \u0111\u1ec3 nguy\u00ean. + L\u1ea5y gi\u1ea5y ho\u1eb7c v\u1ea3i b\u1ecdc k\u00edn chai th\u1ee9 hai. Sau \u0111\u00f3, d\u00f9ng b\u0103ng d\u00ednh bao quanh chai. + R\u00f3t n\u01b0\u1edbc \u1ea5m v\u00e0o m\u1ed7i chai v\u00e0 \u0111\u1eady k\u00edn n\u1eafp. Sau kho\u1ea3ng th\u1eddi gian 15 ph\u00fat, ti\u1ebfn h\u00e0nh so s\u00e1nh nhi\u1ec7t \u0111\u1ed9 c\u1ee7a n\u01b0\u1edbc trong m\u1ed7i chai. \u2013 GV h\u1ecfi HS: + Nhi\u1ec7t \u0111\u1ed9 n\u01b0\u1edbc trong hai chai c\u00f3 kh\u00e1c nhau kh\u00f4ng? V\u00ec sao? + Nh\u1eefng v\u1eadt li\u1ec7u n\u00e0o d\u1eabn nhi\u1ec7t k\u00e9m? \u2013 \u0110\u1ea1i di\u1ec7n c\u00e1c nh\u00f3m tr\u1ea3 l\u1eddi. C\u00e1c HS kh\u00e1c nh\u1eadn x\u00e9t v\u00e0 b\u1ed5 sung. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: Con ng\u01b0\u1eddi \u0111\u00e3 \u1ee9ng d\u1ee5ng t\u00ednh d\u1eabn nhi\u1ec7t t\u1ed1t hay k\u00e9m c\u1ee7a c\u00e1c v\u1eadt li\u1ec7u \u0111\u1ec3 ch\u1ebf t\u1ea1o b\u00ecnh gi\u1eef nhi\u1ec7t, d\u1ee5ng c\u1ee5 l\u00e0m b\u1ebfp,... * Th\u00f4ng tin d\u00e0nh cho GV: C\u1ea5u t\u1ea1o b\u00ecnh gi\u1eef nhi\u1ec7t: B\u00ecnh gi\u1eef nhi\u1ec7t c\u00f3 c\u1ea5u t\u1ea1o nh\u01b0 m\u00f4 t\u1ea3 \u1edf h\u00ecnh 1. C\u00e1c b\u1ed9 ph\u1eadn quan tr\u1ecdng nh\u1ea5t c\u1ee7a b\u00ecnh gi\u1eef nhi\u1ec7t l\u00e0: l\u1edbp c\u00e1ch nhi\u1ec7t, \u0111\u1ebf c\u00e1ch nhi\u1ec7t v\u00e0 m\u1eb7t b\u00ean trong tr\u00e1ng b\u1ea1c. N\u1eafp \u0111\u1eady V\u1ecf nh\u1ef1a H\u1ed9p \u0111\u1ee1 M\u1eb7t trong tr\u00e1ng b\u1ea1c L\u1edbp c\u00e1ch nhi\u1ec7t \u0110\u1ebf c\u00e1ch nhi\u1ec7t H\u00ecnh 1. C\u1ea5u t\u1ea1o b\u00ecnh gi\u1eef nhi\u1ec7t \u2013 GV y\u00eau c\u1ea7u HS \u0111\u1ecdc n\u1ed9i dung Em \u0111\u00e3 h\u1ecdc \u0111\u01b0\u1ee3c: Con ng\u01b0\u1eddi \u0111\u00e3 \u1ee9ng d\u1ee5ng t\u00ednh d\u1eabn nhi\u1ec7t t\u1ed1t hay k\u00e9m c\u1ee7a c\u00e1c v\u1eadt li\u1ec7u \u0111\u1ec3 ch\u1ebf t\u1ea1o d\u1ee5ng c\u1ee5 l\u00e0m b\u1ebfp, b\u00ecnh gi\u1eef nhi\u1ec7t, trang ph\u1ee5c gi\u1eef \u1ea5m,... Ho\u1ea1t \u0111\u1ed9ng ti\u1ebfp n\u1ed1i sau b\u00e0i h\u1ecdc GV y\u00eau c\u1ea7u HS v\u1ec1 nh\u00e0 xem l\u1ea1i b\u00e0i (t\u1eeb b\u00e0i 8 \u0111\u1ebfn b\u00e0i 13); \u0111i\u1ec1u tra v\u1ec1 t\u00ecnh tr\u1ea1ng \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n \u1edf \u0111\u1ecba ph\u01b0\u01a1ng em \u0111\u1ec3 chu\u1ea9n b\u1ecb cho ti\u1ebft \u00f4n t\u1eadp ch\u1ee7 \u0111\u1ec1 n\u0103ng l\u01b0\u1ee3ng. 89","B\u00e0i 14. \u00d4N T\u1eacP CH\u1ee6 \u0110\u1ec0 N\u0102NG L\u01af\u1ee2NG (1 ti\u1ebft) I. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t Sau b\u00e0i h\u1ecdc, HS: \u2013 T\u1ed5ng h\u1ee3p \u0111\u01b0\u1ee3c c\u00e1c ki\u1ebfn th\u1ee9c, k\u0129 n\u0103ng v\u1ec1 c\u00e1c d\u1ea1ng n\u0103ng l\u01b0\u1ee3ng: \u00e1nh s\u00e1ng, \u00e2m thanh, nhi\u1ec7t. \u2013 V\u1eadn d\u1ee5ng \u0111\u01b0\u1ee3c ki\u1ebfn th\u1ee9c v\u1ec1 c\u00e1c d\u1ea1ng n\u0103ng l\u01b0\u1ee3ng: \u00e1nh s\u00e1ng, \u00e2m thanh, nhi\u1ec7t \u0111\u1ec3 gi\u1ea3i th\u00edch m\u1ed9t s\u1ed1 hi\u1ec7n t\u01b0\u1ee3ng t\u1ef1 nhi\u00ean; \u0111\u1ec3 gi\u1ea3i quy\u1ebft m\u1ed9t s\u1ed1 v\u1ea5n \u0111\u1ec1 \u0111\u01a1n gi\u1ea3n trong cu\u1ed9c s\u1ed1ng. II. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc \u2013 GV: SGK, phi\u1ebfu \u0111i\u1ec1u tra theo m\u1eabu (SGK, trang 56). \u2013 HS: SGK, VBT. III. C\u00c1C Ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc Ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng * M\u1ee5c ti\u00eau: \u00d4n t\u1eadp, gi\u00fap HS nh\u1edb l\u1ea1i c\u00e1c d\u1ea1ng n\u0103ng l\u01b0\u1ee3ng \u0111\u00e3 h\u1ecdc trong ch\u1ee7 \u0111\u1ec1. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV \u0111\u1eb7t c\u00e2u h\u1ecfi: Ch\u00fang ta \u0111\u00e3 h\u1ecdc v\u1ec1 c\u00e1c d\u1ea1ng n\u0103ng l\u01b0\u1ee3ng n\u00e0o trong ch\u1ee7 \u0111\u1ec1 N\u0103ng l\u01b0\u1ee3ng? \u2013 GV m\u1eddi m\u1ed9t v\u00e0i HS tr\u1ea3 l\u1eddi. G\u1ee3i \u00fd: C\u00e1c d\u1ea1ng n\u0103ng l\u01b0\u1ee3ng \u0111\u00e3 h\u1ecdc trong ch\u1ee7 \u0111\u1ec1 l\u00e0: \u00e1nh s\u00e1ng, \u00e2m thanh, nhi\u1ec7t. \u2013 GV nh\u1eadn x\u00e9t chung v\u00e0 d\u1eabn d\u1eaft v\u00e0o b\u00e0i h\u1ecdc: \u201c\u00d4n t\u1eadp ch\u1ee7 \u0111\u1ec1 N\u0103ng l\u01b0\u1ee3ng\u201d. Ho\u1ea1t \u0111\u1ed9ng 1: S\u01a1 \u0111\u1ed3 ho\u00e1 * M\u1ee5c ti\u00eau: HS kh\u00e1i qu\u00e1t ho\u00e1 c\u00e1c d\u1ea1ng n\u0103ng l\u01b0\u1ee3ng \u0111\u00e3 h\u1ecdc v\u00e0 vai tr\u00f2 c\u1ee7a c\u00e1c d\u1ea1ng n\u0103ng l\u01b0\u1ee3ng n\u00e0y. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 6, y\u00eau c\u1ea7u HS: H\u00e3y vi\u1ebft, v\u1ebd nh\u1eefng \u0111i\u1ec1u \u0111\u00e3 h\u1ecdc \u0111\u01b0\u1ee3c sau ch\u1ee7 \u0111\u1ec1 N\u0103ng l\u01b0\u1ee3ng theo s\u01a1 \u0111\u1ed3 g\u1ee3i \u00fd \u1edf trang 56 SGK. \u2013 HS c\u00e1c nh\u00f3m th\u1ef1c hi\u1ec7n nhi\u1ec7m v\u1ee5 v\u00e0 chia s\u1ebb v\u1edbi c\u00e1c b\u1ea1n c\u00f9ng l\u1edbp v\u1ec1 s\u1ea3n ph\u1ea9m c\u1ee7a nh\u00f3m. \u2013 GV m\u1eddi HS nh\u1eadn x\u00e9t l\u1eabn nhau. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: M\u1ed7i d\u1ea1ng n\u0103ng l\u01b0\u1ee3ng nh\u01b0 \u00e1nh s\u00e1ng, \u00e2m thanh v\u00e0 nhi\u1ec7t c\u00f3 vai tr\u00f2 quan tr\u1ecdng trong \u0111\u1eddi s\u1ed1ng c\u1ee7a con ng\u01b0\u1eddi, \u0111\u1ed9ng v\u1eadt v\u00e0 th\u1ef1c v\u1eadt. C\u00e1c d\u1ea1ng n\u0103ng l\u01b0\u1ee3ng n\u00e0y \u0111\u01b0\u1ee3c con ng\u01b0\u1eddi s\u1eed d\u1ee5ng tu\u1ef3 theo nhu c\u1ea7u. Ho\u1ea1t \u0111\u1ed9ng 2: Em t\u1eadp l\u00e0m nh\u00e0 khoa ho\u0323c * M\u1ee5c ti\u00eau: HS t\u1eadp l\u00e0m m\u1ed9t nh\u00e0 khoa h\u1ecdc \u0111\u1ec3 \u0111i\u1ec1u tra v\u1ec1 t\u00ecnh tr\u1ea1ng \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n \u1edf \u0111\u1ecba ph\u01b0\u01a1ng. 90","* C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 4, y\u00eau c\u1ea7u HS th\u1ea3o lu\u1eadn nh\u00f3m, trao \u0111\u1ed5i th\u00f4ng tin \u0111\u00e3 \u0111i\u1ec1u tra \u0111\u01b0\u1ee3c v\u1ec1 t\u00ecnh tr\u1ea1ng \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n \u1edf \u0111\u1ecba ph\u01b0\u01a1ng \u0111\u1ec3 ho\u00e0n th\u00e0nh phi\u1ebfu \u0111i\u1ec1u tra theo m\u1eabu (SGK, trang 56). N\u01a1i\/ \u0110\u1ecba \u0111i\u1ec3m T\u00ecnh tr\u1ea1ng Nguy\u00ean nh\u00e2n H\u1eadu qu\u1ea3 \u0110\u1ec1 xu\u1ea5t \u00f4 nhi\u1ec5m g\u00e2y \u00f4 nhi\u1ec5m Khu d\u00e2n c\u01b0 Ti\u1ebfng \u1ed3n sau Loa ph\u00e1t M\u1ea5t ng\u1ee7 Trao \u0111\u1ed5i v\u1edbi ng\u01b0\u1eddi ca 10 gi\u1edd t\u1ed1i ti\u1ebfng h\u00e1t h\u00e1t \u0111\u1ec3 gi\u1ea3m \u00e2m thanh ? ? ?? ? \u2013 HS l\u00e0m vi\u1ec7c theo nh\u00f3m. GV quan s\u00e1t v\u00e0 h\u1ed7 tr\u1ee3 c\u00e1c nh\u00f3m khi c\u1ea7n. \u2013 GV t\u1ed5 ch\u1ee9c cho c\u00e1c nh\u00f3m l\u00ean chia s\u1ebb v\u1ec1: + T\u00ecnh tr\u1ea1ng \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n \u1edf \u0111\u1ecba ph\u01b0\u01a1ng. + Nh\u1eefng nguy\u00ean nh\u00e2n g\u00e2y \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n. + Nh\u1eefng vi\u1ec7c n\u00ean l\u00e0m \u0111\u1ec3 gi\u1ea3m t\u00e1c h\u1ea1i c\u1ee7a ti\u1ebfng \u1ed3n. \u2013 HS l\u1eafng nghe v\u00e0 nh\u1eadn x\u00e9t cho nh\u00f3m b\u1ea1n. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 tuy\u00ean d\u01b0\u01a1ng nh\u1eefng nh\u00f3m c\u00f3 nhi\u1ec1u s\u00e1ng t\u1ea1o, thuy\u1ebft tr\u00ecnh hay, l\u01b0u lo\u00e1t. \u2013 GV l\u1ed3ng gh\u00e9p gi\u00e1o d\u1ee5c HS: kh\u00f4ng g\u00e2y \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n, th\u1ef1c hi\u1ec7n c\u00e1c bi\u1ec7n ph\u00e1p \u0111\u1ec3 l\u00e0m gi\u1ea3m \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n v\u00e0 tuy\u00ean truy\u1ec1n m\u1ecdi ng\u01b0\u1eddi c\u00f9ng th\u1ef1c hi\u1ec7n. Ho\u1ea1t \u0111\u1ed9ng ti\u1ebfp n\u1ed1i sau b\u00e0i h\u1ecdc GV y\u00eau c\u1ea7u HS v\u1ec1 nh\u00e0 xem b\u00e0i tr\u01b0\u1edbc \u0111\u1ec3 chu\u1ea9n b\u1ecb ti\u1ebft sau h\u1ecdc v\u1ec1 ch\u1ee7 \u0111\u1ec1 Th\u1ef1c v\u1eadt v\u00e0 \u0111\u1ed9ng v\u1eadt. 91","Chu\u00fb \u00f1e\u00e0 3: TH\u00d6\u00cfC VA\u00c4T VA\u00d8 \u00d1O\u00c4NG VA\u00c4T B\u00e0i 15. TH\u1ef0C V\u1eacT C\u1ea6N G\u00cc \u0110\u1ec2 S\u1ed0NG V\u00c0 PH\u00c1T TRI\u1ec2N? (3 ti\u1ebft) I. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t Sau b\u00e0i h\u1ecdc, HS: \u2212 Nh\u1ea1\u0302n bi\u00ea\u0301t \u0111u\u031b\u01a1\u0323c ca\u0301c y\u00ea\u0301u t\u00f4\u0301 c\u00e2\u0300n cho s\u01b0\u0323 s\u00f4\u0301ng va\u0300 pha\u0301t tri\u00ea\u0309n cu\u0309a th\u01b0\u0323c v\u1ea1\u0302t (a\u0301nh sa\u0301ng, kho\u0302ng khi\u0301, nu\u031b\u01a1\u0301c, ch\u00e2\u0301t khoa\u0301ng va\u0300 nhi\u1eb9\u0302t \u0111\u1ecd\u0302) tho\u0302ng qua thi\u0301 nghi\u1eb9\u0302m ho\u1ea1\u0306c quan sa\u0301t tranh a\u0309nh, video clip. \u2212 Tri\u0300nh ba\u0300y \u0111u\u031b\u01a1\u0323c th\u01b0\u0323c v\u1ea1\u0302t co\u0301 kha\u0309 na\u0306ng t\u01b0\u0323 t\u00f4\u0309ng h\u01a1\u0323p ch\u00e2\u0301t dinh du\u031b\u01a1\u0303ng c\u00e2\u0300n cho s\u01b0\u0323 s\u00f4\u0301ng. \u2212 Ve\u0303 \u0111u\u031b\u01a1\u0323c so\u031b \u0111\u00f4\u0300 \u0111o\u031bn gia\u0309n (ho\u1ea1\u0306c \u0111i\u00ea\u0300n va\u0300o so\u031b \u0111\u00f4\u0300 cho tru\u031b\u01a1\u0301c) v\u00ea\u0300 s\u01b0\u0323 trao \u0111\u00f4\u0309i khi\u0301, nu\u031b\u01a1\u0301c, ch\u00e2\u0301t khoa\u0301ng cu\u0309a th\u01b0\u0323c v\u1ea1\u0302t v\u01a1\u0301i mo\u0302i tru\u031b\u01a1\u0300ng. II. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc \u2013 GV: C\u00e1c h\u00ecnh trong b\u00e0i 15 SGK, phi\u1ebfu h\u1ecdc t\u1eadp, d\u1ee5ng c\u1ee5, v\u1eadt li\u1ec7u l\u00e0m th\u00ed nghi\u1ec7m nh\u01b0 m\u00f4 t\u1ea3 \u1edf h\u00ecnh 10 trang 62 SGK. \u2013 HS: SGK, VBT, b\u00fat, c\u00e1c th\u1ebb b\u00eca, d\u00e2y bu\u1ed9c. III. C\u00c1C Ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc Ti\u1ebft 1 Ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng * M\u1ee5c ti\u00eau: T\u1ea1o h\u1ee9ng th\u00fa v\u00e0 kh\u01a1i g\u1ee3i nh\u1eefng hi\u1ec3u bi\u1ebft \u0111\u00e3 c\u00f3 c\u1ee7a HS v\u1ec1 th\u1ee9c \u0103n c\u1ee7a th\u1ef1c v\u1eadt, v\u1ec1 vi\u1ec7c l\u00e0m th\u1ebf n\u00e0o \u0111\u1ec3 th\u1ef1c v\u1eadt c\u00f3 th\u1ec3 s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV t\u1ed5 ch\u1ee9c cho HS quan s\u00e1t h\u00ecnh 1 (SGK, trang 58) ho\u1eb7c c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng c\u00e1c tranh v\u1ebd, video kh\u00e1c c\u00f3 n\u1ed9i dung t\u01b0\u01a1ng t\u1ef1 \u0111\u1ec3 t\u1ed5 ch\u1ee9c ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng. \u2013 GV \u0111\u1eb7t c\u00e2u h\u1ecfi: + C\u00e2y \u0111\u1eadu c\u00f3 c\u1ea7n th\u1ee9c \u0103n \u0111\u1ec3 s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n kh\u00f4ng? + Th\u1ee9c \u0103n c\u1ee7a c\u00e2y \u0111\u1eadu l\u00e0 g\u00ec? \u2013 GV m\u1eddi 1 \u2013 2 HS b\u1ea5t k\u00ec tr\u1ea3 l\u1eddi c\u00e2u h\u1ecfi. \u2013 D\u1ef1a v\u00e0o th\u1ef1c t\u1ebf c\u00e2u tr\u1ea3 l\u1eddi c\u1ee7a HS, GV ghi ch\u00fa m\u1ed9t s\u1ed1 y\u1ebfu t\u1ed1 c\u00f3 li\u00ean quan l\u00ean b\u1ea3ng, nh\u1eadn x\u00e9t chung v\u00e0 d\u1eabn d\u1eaft v\u00e0o b\u00e0i h\u1ecdc: \u201cTh\u1ef1c v\u1eadt c\u1ea7n g\u00ec \u0111\u1ec3 s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n?\u201d. 92","Ho\u1ea1t \u0111\u1ed9ng 1: Ca\u0301c y\u00ea\u0301u t\u1ed1 c\u1ea7n cho s\u1ef1 s\u1ed1ng va\u0300 pha\u0301t tri\u1ec3n c\u1ee7a th\u1ef1c v\u1ea1\u0302t * M\u1ee5c ti\u00eau: HS nh\u1ea1\u0302n bi\u00ea\u0301t \u0111u\u031b\u01a1\u0323c ca\u0301c y\u00ea\u0301u t\u00f4\u0301 c\u00e2\u0300n cho s\u01b0\u0323 s\u00f4\u0301ng va\u0300 pha\u0301t tri\u00ea\u0309n cu\u0309a th\u01b0\u0323c v\u1ea1\u0302t (a\u0301nh sa\u0301ng, kho\u0302ng khi\u0301, nu\u031b\u01a1\u0301c, ch\u00e2\u0301t khoa\u0301ng va\u0300 nhi\u1eb9\u0302t \u0111\u1ecd\u0302) tho\u0302ng qua thi\u0301 nghi\u1eb9\u0302m ho\u1ea1\u0306c quan sa\u0301t tranh a\u0309nh, video clip. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV tu\u1ef3 theo \u0111i\u1ec1u ki\u1ec7n c\u01a1 s\u1edf v\u1eadt ch\u1ea5t, tr\u00ecnh \u0111\u1ed9 c\u1ee7a HS \u0111\u1ec3 c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng ph\u01b0\u01a1ng \u00e1n l\u00e0m th\u00ed nghi\u1ec7m, quan s\u00e1t tranh v\u1ebd m\u00f4 t\u1ea3 th\u00ed nghi\u1ec7m trong SGK hay khai th\u00e1c qua video clip th\u00ed nghi\u1ec7m. N\u1ebfu c\u00f3 \u0111i\u1ec1u ki\u1ec7n th\u00ec ph\u01b0\u01a1ng \u00e1n d\u1ea1y h\u1ecdc qua th\u00ed nghi\u1ec7m l\u00e0 ph\u01b0\u01a1ng \u00e1n \u01b0u ti\u00ean nh\u1ea5t. Trong t\u00e0i li\u1ec7u n\u00e0y, ch\u00fang t\u00f4i tr\u00ecnh b\u00e0y ph\u01b0\u01a1ng \u00e1n \u0111\u01a1n gi\u1ea3n nh\u1ea5t l\u00e0 ph\u01b0\u01a1ng \u00e1n quan s\u00e1t v\u00e0 khai th\u00e1c d\u1ef1a tr\u00ean c\u00e1c h\u00ecnh v\u1ebd 2a, 2b; 3a, 3b; 4a, 4b; 5a, 5b; 6a, 6b (SGK, trang 58 v\u00e0 59) m\u00f4 t\u1ea3 c\u00e1c th\u00ed nghi\u1ec7m 1, 2, 3, 4. \u2013 Trong tr\u01b0\u1eddng h\u1ee3p GV c\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n th\u00ed nghi\u1ec7m kh\u00e1m ph\u00e1 ki\u1ebfn th\u1ee9c (n\u1ebfu tr\u01b0\u1eddng c\u00f3 \u0111i\u1ec1u ki\u1ec7n), vi\u1ec7c ti\u1ebfn h\u00e0nh c\u00e1c th\u00ed nghi\u1ec7m ph\u1ea3i \u0111\u01b0\u1ee3c tri\u1ec3n khai v\u00e0 b\u1eaft \u0111\u1ea7u th\u1ef1c hi\u1ec7n tr\u01b0\u1edbc b\u1ea3y ng\u00e0y, t\u00ednh t\u1edbi ng\u00e0y th\u1ef1c hi\u1ec7n ti\u1ebft h\u1ecdc l\u00e0 t\u00e1m ng\u00e0y. Trong th\u1ef1c t\u1ebf th\u00ec s\u1ed1 ng\u00e0y l\u00e0m th\u00ed nghi\u1ec7m c\u00f3 th\u1ec3 ch\u1eadm th\u00eam t\u1eeb m\u1ed9t \u0111\u1ebfn hai ng\u00e0y c\u0169ng kh\u00f4ng \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn k\u1ebft qu\u1ea3. Tu\u1ef3 theo \u0111i\u1ec1u ki\u1ec7n m\u1ed7i tr\u01b0\u1eddng, c\u00e1c th\u00ed nghi\u1ec7m c\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n t\u1ea1i v\u01b0\u1eddn tr\u01b0\u1eddng ho\u1eb7c c\u00e1c khu v\u1ef1c c\u00f3 th\u1ec3 b\u1ed1 tr\u00ed ph\u00f9 h\u1ee3p. L\u01b0u \u00fd: Th\u00ed nghi\u1ec7m c\u00f3 giai \u0111o\u1ea1n t\u01b0\u1edbi n\u01b0\u1edbc n\u00ean c\u1ea7n c\u1ea9n th\u1eadn tr\u1eddi m\u01b0a, c\u1ea7n \u0111\u1eb7t c\u00e2y \u1edf ch\u1ed7 c\u00f3 \u00e1nh s\u00e1ng \u0111\u1ea7y \u0111\u1ee7 nh\u01b0ng kh\u00f4ng b\u1ecb \u1ea3nh h\u01b0\u1edfng b\u1edfi n\u01b0\u1edbc m\u01b0a. Ch\u1ecdn c\u00e1c c\u00e2y th\u00e2n th\u1ea3o, l\u00e1 to \u0111\u1ec3 d\u1ec5 quan s\u00e1t k\u1ebft qu\u1ea3. \u0110\u1ed1i v\u1edbi th\u00ed nghi\u1ec7m che \u00e1nh s\u00e1ng, kh\u00f4ng n\u00ean d\u00f9ng c\u00e1c c\u00e2y ch\u1ecbu b\u00f3ng v\u00ec s\u1ebd \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn \u0111i\u1ec1u ki\u1ec7n th\u00ed nghi\u1ec7m. \u0110\u1ed1i v\u1edbi c\u00e1c c\u00e2y th\u00ed nghi\u1ec7m c\u00f3 t\u01b0\u1edbi n\u01b0\u1edbc, t\u01b0\u1edbi c\u00e2y m\u1ed7i ng\u00e0y hai l\u1ea7n v\u00e0o bu\u1ed5i s\u00e1ng v\u00e0 bu\u1ed5i chi\u1ec1u v\u1edbi l\u01b0\u1ee3ng n\u01b0\u1edbc t\u01b0\u01a1ng \u0111\u01b0\u01a1ng nhau. \u0110\u1ed1i v\u1edbi nhi\u1ec7t \u0111\u1ed9 m\u00f4i tr\u01b0\u1eddng, GV c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng nhi\u1ec7t k\u1ebf \u0111o \u1edf \u0111i\u1ec1u ki\u1ec7n b\u00ecnh th\u01b0\u1eddng \u0111\u1ec3 l\u1ea5y nhi\u1ec7t \u0111\u1ed9 t\u01b0\u01a1ng \u0111\u1ed1i, n\u1ebfu kh\u00f4ng c\u00f3 nhi\u1ec7t k\u1ebf th\u00ec coi nh\u01b0 nhi\u1ec7t \u0111\u1ed9 m\u00f4i tr\u01b0\u1eddng c\u1ee7a c\u00e1c c\u00e2y th\u00ed nghi\u1ec7m l\u00e0 nh\u01b0 nhau v\u00e0 ch\u1ecdn nhi\u1ec7t \u0111\u1ed9 trong ch\u01b0\u01a1ng tr\u00ecnh d\u1ef1 b\u00e1o th\u1eddi ti\u1ebft h\u1eb1ng ng\u00e0y t\u1ea1i \u0111\u1ecba ph\u01b0\u01a1ng \u0111\u1ec3 l\u01b0u \u00fd v\u1edbi HS. N\u00ean t\u1ed5 ch\u1ee9c cho HS l\u00e0m th\u00ed nghi\u1ec7m l\u1eb7p l\u1ea1i ba l\u1ea7n c\u00f9ng l\u00fac \u0111\u1ec3 ch\u1ee9ng minh tr\u1ea1ng th\u00e1i c\u00e1c c\u00e2y l\u00e0 nh\u01b0 nhau v\u00e0 ph\u00f2ng tr\u01b0\u1eddng h\u1ee3p c\u00e2y b\u1ecb h\u1ecfng do c\u00e1c y\u1ebfu t\u1ed1 ngo\u1ea1i c\u1ea3nh kh\u00e1c, v\u00ed d\u1ee5: chu\u1ed9t c\u1eafn ph\u00e1,\u2026 \u2013 GV y\u00eau c\u1ea7u HS quan s\u00e1t t\u1eebng c\u1eb7p c\u00e1c ch\u1eadu c\u00e2y \u1edf c\u00f9ng \u0111i\u1ec1u ki\u1ec7n th\u00ed nghi\u1ec7m v\u00e0 c\u00e1c c\u1eb7p c\u00e2y \u1edf th\u00ed nghi\u1ec7m 1, 2, 3, 4 v\u1edbi c\u00e2y \u0111\u1ed1i ch\u1ee9ng. Trong tr\u01b0\u1eddng h\u1ee3p kh\u00f4ng c\u00f3 \u0111i\u1ec1u ki\u1ec7n \u0111\u1ec3 l\u00e0m th\u00ed nghi\u1ec7m, GV c\u00f3 th\u1ec3 cho HS quan s\u00e1t c\u00e1c h\u00ecnh m\u00f4 ph\u1ecfng th\u00ed nghi\u1ec7m c\u00f3 trong SGK. GV y\u00eau c\u1ea7u HS l\u00e0m vi\u1ec7c nh\u00f3m 2 v\u00e0 ho\u00e0n th\u00e0nh phi\u1ebfu quan s\u00e1t theo g\u1ee3i \u00fd \u1edf trang 60 SGK b\u1eb1ng c\u00e1ch \u0111\u1ecdc th\u00f4ng tin m\u00f4 t\u1ea3 th\u00ed nghi\u1ec7m, quan s\u00e1t c\u00e2y \u0111\u1ed1i ch\u1ee9ng \u1edf h\u00ecnh 2a (ng\u00e0y th\u1ee9 nh\u1ea5t), 2b (ng\u00e0y th\u1ee9 8). Ti\u1ebfp theo, l\u00e0m t\u01b0\u01a1ng t\u1ef1 \u0111\u1ed1i v\u1edbi c\u00e2y th\u00ed nghi\u1ec7m 1 (h\u00ecnh 3a, 3b), c\u00e2y th\u00ed nghi\u1ec7m 2 (h\u00ecnh 4a, 4b), c\u00e2y th\u00ed nghi\u1ec7m 3 (5a, 5b), c\u00e2y th\u00ed nghi\u1ec7m 4 (h\u00ecnh 6a, 6b). \u2013 GV \u0111\u01b0a ra c\u00e1c nhi\u1ec7m v\u1ee5 ho\u1eb7c \u0111\u1eb7t c\u00e2u h\u1ecfi \u0111\u1ec3 g\u1ee3i \u00fd HS quan s\u00e1t: + H\u00e3y cho bi\u1ebft c\u00e1c \u0111i\u1ec1u ki\u1ec7n ch\u0103m s\u00f3c c\u00e2y nh\u01b0 n\u01b0\u1edbc, \u00e1nh s\u00e1ng, kh\u00f4ng kh\u00ed, ch\u1ea5t kho\u00e1ng, nhi\u1ec7t \u0111\u1ed9 th\u00edch h\u1ee3p cho c\u00e2y \u0111\u1ed1i ch\u1ee9ng. + H\u00e3y cho bi\u1ebft c\u00e1c \u0111i\u1ec1u ki\u1ec7n ch\u0103m s\u00f3c c\u00e2y nh\u01b0 n\u01b0\u1edbc, \u00e1nh s\u00e1ng, kh\u00f4ng kh\u00ed, ch\u1ea5t kho\u00e1ng, nhi\u1ec7t \u0111\u1ed9 th\u00edch h\u1ee3p cho c\u00e1c c\u00e2y \u1edf th\u00ed nghi\u1ec7m 1, 2, 3, 4. 93","+ C\u00e2y \u1edf th\u00ed nghi\u1ec7m 1, 2, 3, 4 v\u00e0o ng\u00e0y th\u1ee9 8 c\u00f3 hi\u1ec7n t\u01b0\u1ee3ng g\u00ec? V\u00ec sao c\u00e2y l\u1ea1i c\u00f3 tr\u1ea1ng th\u00e1i nh\u01b0 v\u1eady? + V\u00ec sao c\u00e2y \u0111\u1ed1i ch\u1ee9ng \u1edf ng\u00e0y th\u1ee9 8 v\u1eabn s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n b\u00ecnh th\u01b0\u1eddng? G\u1ee3i \u00fd: + C\u00e1c \u0111i\u1ec1u ki\u1ec7n ch\u0103m s\u00f3c: n\u01b0\u1edbc, \u00e1nh s\u00e1ng, kh\u00f4ng kh\u00ed, nhi\u1ec7t \u0111\u1ed9 th\u00edch h\u1ee3p, ch\u1ea5t kho\u00e1ng \u0111\u1ec1u \u0111\u1ea7y \u0111\u1ee7 v\u00e0 \u0111\u1ea3m b\u1ea3o nhu c\u1ea7u c\u1ee7a c\u00e2y. + \u0110i\u1ec1u ki\u1ec7n ch\u0103m s\u00f3c \u0111\u1ed1i v\u1edbi: \u2022\t C\u00e2y \u1edf th\u00ed nghi\u1ec7m 1: Kh\u00f4ng \u0111\u01b0\u1ee3c t\u01b0\u1edbi n\u01b0\u1edbc. \u2022\t C\u00e2y \u1edf th\u00ed nghi\u1ec7m 2: Kh\u00f4ng \u0111\u01b0\u1ee3c nh\u1eadn \u00e1nh s\u00e1ng (b\u1ecb che l\u1ea1i b\u1eb1ng m\u1ed9t h\u1ed9p gi\u1ea5y c\u00f3 \u0111\u1ee5c l\u1ed7 \u1edf hai b\u00ean). \u2022\t C\u00e2y \u1edf th\u00ed nghi\u1ec7m 3: Kh\u00f4ng th\u1ec3 trao \u0111\u1ed5i kh\u00ed v\u1edbi m\u00f4i tr\u01b0\u1eddng v\u00ec l\u00e1 \u0111\u00e3 b\u1ecb b\u00f4i keo che h\u1ebft c\u00e1c l\u1ed7 kh\u00ed tr\u00ean l\u00e1. \u2022\t C\u00e2y \u1edf th\u00ed nghi\u1ec7m 4: C\u00e2y kh\u00f4ng \u0111\u01b0\u1ee3c cung c\u1ea5p ch\u1ea5t kho\u00e1ng v\u00ec kh\u00f4ng \u0111\u01b0\u1ee3c tr\u1ed3ng trong \u0111\u1ea5t. \u2192 C\u00e1c c\u00e2y th\u00ed nghi\u1ec7m \u0111\u1ec1u \u0111\u01b0\u1ee3c \u0111\u1eb7t trong m\u00f4i tr\u01b0\u1eddng c\u00f3 nhi\u1ec7t \u0111\u1ed9 th\u00edch h\u1ee3p. + Hi\u1ec7n t\u01b0\u1ee3ng x\u1ea3y ra \u1edf ng\u00e0y th\u1ee9 8: \u2022 C\u00e2y \u1edf th\u00ed nghi\u1ec7m 1: C\u00e2y h\u00e9o r\u0169 v\u00e0 ch\u1ebft. Gi\u1ea3i th\u00edch: V\u00ec c\u00e2y kh\u00f4ng \u0111\u01b0\u1ee3c t\u01b0\u1edbi n\u01b0\u1edbc. \u2022\t C\u00e2y \u1edf th\u00ed nghi\u1ec7m 2: L\u00e1 c\u00e2y \u00faa v\u00e0ng ho\u1eb7c ng\u1ea3 m\u00e0u v\u00e0ng nh\u1ea1t, m\u1ed9t s\u1ed1 l\u00e1 b\u1ecb r\u1ee5ng \u1edf ng\u00e0y th\u1ee9 8, c\u00e2y kh\u00f4ng ph\u00e1t tri\u1ec3n b\u00ecnh th\u01b0\u1eddng, th\u00e2n h\u01a1i m\u1ecdc cao l\u00ean. Gi\u1ea3i th\u00edch: V\u00ec c\u00e2y kh\u00f4ng \u0111\u01b0\u1ee3c nh\u1eadn \u00e1nh s\u00e1ng \u0111\u1ea7y \u0111\u1ee7 \u0111\u1ec3 th\u1ef1c hi\u1ec7n quang h\u1ee3p. \u2022\t C\u00e2y \u1edf th\u00ed nghi\u1ec7m 3: L\u00e1 c\u00e2y \u1ee7 r\u0169, m\u1ed9t s\u1ed1 l\u00e1 b\u1ecb r\u1ee5ng, c\u00e2y kh\u00f4ng ph\u00e1t tri\u1ec3n b\u00ecnh th\u01b0\u1eddng. Gi\u1ea3i th\u00edch: V\u00ec l\u00e1 c\u00e2y \u0111\u00e3 b\u1ecb b\u00f4i keo kh\u00f4ng th\u1ec3 trao \u0111\u1ed5i kh\u00ed v\u1edbi m\u00f4i tr\u01b0\u1eddng. C\u00e2y kh\u00f4ng nh\u1eadn \u0111\u01b0\u1ee3c kh\u00ed c\u00e1c-b\u00f4-n\u00edc c\u00f3 trong kh\u00f4ng kh\u00ed \u0111\u1ec3 quang h\u1ee3p v\u00e0 c\u0169ng kh\u00f4ng nh\u1eadn \u0111\u01b0\u1ee3c kh\u00ed \u00f4-xi \u0111\u1ec3 h\u00f4 h\u1ea5p. \u2022\t C\u00e2y \u1edf th\u00ed nghi\u1ec7m 4: L\u00e1 c\u00e2y \u1ee7 r\u1ee7, c\u00e2y b\u1ecb \u00faa v\u00e0ng. Gi\u1ea3i th\u00edch: V\u00ec c\u00e2y kh\u00f4ng \u0111\u01b0\u1ee3c tr\u1ed3ng trong \u0111\u1ea5t m\u00e0 tr\u1ed3ng trong s\u1ecfi \u0111\u00e3 r\u1eeda s\u1ea1ch n\u00ean kh\u00f4ng c\u00f3 ch\u1ea5t kho\u00e1ng. + C\u00e2y \u0111\u1ed1i ch\u1ee9ng \u1edf ng\u00e0y th\u1ee9 8 v\u1eabn s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n b\u00ecnh th\u01b0\u1eddng v\u00ec c\u00e2y \u0111\u01b0\u1ee3c ch\u0103m s\u00f3c v\u1edbi c\u00e1c \u0111i\u1ec1u ki\u1ec7n n\u01b0\u1edbc, \u00e1nh s\u00e1ng, kh\u00f4ng kh\u00ed, ch\u1ea5t kho\u00e1ng \u0111\u1ea7y \u0111\u1ee7. C\u00e2y \u0111\u01b0\u1ee3c s\u1ed1ng trong nhi\u1ec7t \u0111\u1ed9 m\u00f4i tr\u01b0\u1eddng th\u00edch h\u1ee3p. \u2013 GV m\u1eddi 4 \u2013 5 HS chia s\u1ebb tr\u01b0\u1edbc l\u1edbp c\u00e1c th\u00f4ng tin \u0111\u00e3 \u0111i\u1ec1n v\u00e0o phi\u1ebfu quan s\u00e1t k\u1ebft qu\u1ea3 th\u00ed nghi\u1ec7m \u1edf c\u00e2y \u0111\u1ed1i ch\u1ee9ng v\u00e0 c\u00e1c c\u00e2y \u1edf th\u00ed nghi\u1ec7m 1, 2, 3, 4; k\u1ebft qu\u1ea3 quan s\u00e1t \u0111\u01b0\u1ee3c gi\u1ea3i th\u00edch l\u1ed3ng gh\u00e9p v\u1edbi c\u00e1c c\u00e2u h\u1ecfi \u1edf tr\u00ean theo tr\u00ecnh t\u1ef1 th\u00ed nghi\u1ec7m t\u1eeb tr\u00ean xu\u1ed1ng. \u2013 HS tr\u1ea3 l\u1eddi v\u00e0 nh\u1eadn x\u00e9t l\u1eabn nhau d\u01b0\u1edbi s\u1ef1 \u0111i\u1ec1u khi\u1ec3n c\u1ee7a GV. \u2013 GV nh\u1eadn x\u00e9t, k\u1ebft lu\u1eadn v\u00e0 th\u1ed1ng nh\u1ea5t chung cho c\u1ea3 l\u1edbp \u0111\u1ec3 ho\u00e0n thi\u1ec7n phi\u1ebfu quan s\u00e1t k\u1ebft qu\u1ea3 th\u00ed nghi\u1ec7m. 94","G\u1ee3i \u00fd th\u00f4ng tin \u0111i\u1ec1n v\u00e0o phi\u1ebfu quan s\u00e1t: PHI\u1ebeU QUAN S\u00c1T T\u00ean c\u00e2y N\u01b0\u1edbc \u00c1nh Kh\u00f4ng Ch\u1ea5t K\u1ebft qu\u1ea3 quan s\u00e1t Gi\u1ea3i th\u00edch k\u1ebft s\u00e1ng kh\u00ed kho\u00e1ng \u1edf ng\u00e0y th\u1ee9 8 qu\u1ea3 th\u00ed nghi\u1ec7m C\u00e2y \u0111\u1ed1i C\u00f3 C\u00f3 C\u00f3 C\u00f3 C\u00e2y s\u1ed1ng b\u00ecnh V\u00ec c\u00e2y c\u00f3 \u0111\u1ea7y \u0111\u1ee7 c\u00e1c ch\u1ee9ng th\u01b0\u1eddng. y\u1ebfu t\u1ed1 \u0111\u1ec3 s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n. C\u00e2y th\u00ed Kh\u00f4ng C\u00f3 C\u00f3 C\u00f3 C\u00e2y b\u1ecb h\u00e9o r\u0169. V\u00ec c\u00e2y thi\u1ebfu n\u01b0\u1edbc. nghi\u1ec7m 1 C\u00e2y th\u00ed C\u00f3 Kh\u00f4ng C\u00f3 C\u00f3 L\u00e1 c\u00e2y \u00faa v\u00e0ng V\u00ec thi\u1ebfu \u00e1nh s\u00e1ng n\u00ean nghi\u1ec7m ho\u1eb7c ng\u00e3 m\u00e0u c\u00e2y kh\u00f4ng th\u1ec3 quang v\u00e0ng nh\u1ea1t, m\u1ed9t s\u1ed1 h\u1ee3p \u0111\u1ec3 t\u1ea1o ch\u1ea5t dinh 2 l\u00e1 b\u1ecb r\u1ee5ng \u1edf ng\u00e0y d\u01b0\u1ee1ng nu\u00f4i c\u00e2y. th\u1ee9 8, c\u00e2y kh\u00f4ng ph\u00e1t tri\u1ec3n b\u00ecnh th\u01b0\u1eddng. C\u00e2y th\u00ed C\u00f3 C\u00f3 Kh\u00f4ng C\u00f3 L\u00e1 c\u00e2y \u1ee7 r\u0169, m\u1ed9t C\u00e2y kh\u00f4ng nh\u1eadn \u0111\u01b0\u1ee3c nghi\u1ec7m s\u1ed1 l\u00e1 b\u1ecb r\u1ee5ng, c\u00e2y kh\u00ed c\u00e1c-b\u00f4-n\u00edc c\u00f3 trong kh\u00f4ng ph\u00e1t tri\u1ec3n kh\u00f4ng kh\u00ed \u0111\u1ec3 quang 3 b\u00ecnh th\u01b0\u1eddng. h\u1ee3p v\u00e0 c\u0169ng kh\u00f4ng nh\u1eadn \u0111\u01b0\u1ee3c kh\u00ed \u00f4-xi \u0111\u1ec3 h\u00f4 h\u1ea5p. C\u00e2y th\u00ed C\u00f3 C\u00f3 C\u00f3 Kh\u00f4ng L\u00e1 c\u00e2y \u1ee7 r\u1ee7, c\u00e2y b\u1ecb V\u00ec s\u1ecfi r\u1eeda s\u1ea1ch kh\u00f4ng nghi\u1ec7m \u00faa v\u00e0ng. c\u00f3 ch\u1ea5t kho\u00e1ng. 4 \u2013 GV h\u01b0\u1edbng d\u1eabn HS r\u00fat ra k\u1ebft lu\u1eadn. * K\u1ebft lu\u1eadn: C\u00e2y xanh c\u1ea7n n\u01b0\u1edbc, \u00e1nh s\u00e1ng, kh\u00f4ng kh\u00ed, ch\u1ea5t kho\u00e1ng v\u00e0 nhi\u1ec7t \u0111\u1ed9 th\u00edch h\u1ee3p \u0111\u1ec3 s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n. N\u1ebfu thi\u1ebfu m\u1ed9t trong c\u00e1c y\u1ebfu t\u1ed1 quan tr\u1ecdng n\u00e0y th\u00ec c\u00e2y kh\u00f4ng th\u1ec3 ph\u00e1t tri\u1ec3n b\u00ecnh th\u01b0\u1eddng, n\u1ebfu k\u00e9o d\u00e0i th\u00ec c\u00e2y s\u1ebd ch\u1ebft. Ho\u1ea1t \u0111\u1ed9ng 2: \u0110\u1ed1 em * M\u1ee5c ti\u00eau: HS hi\u1ec3u v\u00e0 v\u1eadn d\u1ee5ng \u0111\u01b0\u1ee3c c\u00e1c ki\u1ebfn th\u1ee9c \u0111\u00e3 h\u1ecdc v\u1ec1 c\u00e1c y\u1ebfu t\u1ed1 c\u1ea7n thi\u1ebft cho c\u00e2y s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n \u0111\u1ec3 gi\u1ea3i th\u00edch t\u00ecnh hu\u1ed1ng th\u1ef1c t\u1ebf. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV t\u1ed5 ch\u1ee9c cho HS quan s\u00e1t h\u00ecnh 7 (SGK, trang 60) v\u00e0 \u0111\u1eb7t c\u00e2u h\u1ecfi: N\u1ebfu th\u1eddi ti\u1ebft n\u1eafng n\u00f3ng k\u00e9o d\u00e0i th\u00ec nh\u1eefng c\u00e2y l\u00faa \u1edf trong h\u00ecnh c\u00f3 s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n kh\u00f4ng? Gi\u1ea3i th\u00edch. 95","\u2013 GV m\u1eddi 1 \u2013 2 HS tr\u1ea3 l\u1eddi c\u00e2u h\u1ecfi v\u00e0 \u0111\u01b0a ra l\u1eddi gi\u1ea3i th\u00edch h\u1ee3p l\u00ed. N\u1ebfu HS \u0111\u1ea7u ti\u00ean kh\u00f4ng tr\u1ea3 l\u1eddi ch\u00ednh x\u00e1c th\u00ec g\u1ecdi HS ti\u1ebfp theo. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 ch\u1ed1t l\u1ea1i: N\u1ebfu th\u1eddi ti\u1ebft n\u1eafng n\u00f3ng k\u00e9o d\u00e0i th\u00ec nh\u1eefng c\u00e2y l\u00faa \u1edf trong h\u00ecnh 7 s\u1ebd kh\u00f4ng th\u1ec3 s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n \u0111\u01b0\u1ee3c v\u00ec c\u00e2y b\u1ecb thi\u1ebfu n\u01b0\u1edbc. N\u1ebfu k\u00e9o d\u00e0i t\u00ecnh tr\u1ea1ng n\u00e0y th\u00ec c\u00e2y s\u1ebd ch\u1ebft. \u2013 GV c\u0169ng c\u00f3 th\u1ec3 m\u1edf r\u1ed9ng th\u00eam cho HS b\u1eb1ng c\u00e1ch \u0111\u01b0a ra c\u00e1c t\u00ecnh hu\u1ed1ng v\u1ec1 c\u00e2y \u1edf n\u01a1i l\u1ea1nh gi\u00e1 c\u00f3 b\u0103ng tuy\u1ebft bao ph\u1ee7, nhi\u1ec7t \u0111\u1ed9 th\u1ea5p k\u00e9o d\u00e0i; c\u00e2y tr\u1ed3ng \u1edf nh\u1eefng n\u01a1i thi\u1ebfu \u00e1nh s\u00e1ng, thi\u1ebfu ch\u1ea5t kho\u00e1ng (c\u00f3 h\u00ecnh \u1ea3nh th\u1ef1c t\u1ebf) \u0111\u1ec3 cho HS quan s\u00e1t v\u00e0 nh\u1eadn x\u00e9t th\u00eam n\u1ebfu th\u1eddi gian cho ph\u00e9p. Ho\u1ea1t \u0111\u1ed9ng ti\u1ebfp n\u1ed1i sau b\u00e0i h\u1ecdc GV y\u00eau c\u1ea7u HS v\u1ec1 nh\u00e0 quan s\u00e1t, s\u01b0u t\u1ea7m tranh \u1ea3nh v\u1ec1 c\u00e2y b\u1ecb thi\u1ebfu n\u01b0\u1edbc, thi\u1ebfu \u00e1nh s\u00e1ng, thi\u1ebfu kh\u00f4ng kh\u00ed khi\u1ebfn c\u00e2y kh\u00f4ng th\u1ec3 s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n b\u00ecnh th\u01b0\u1eddng \u0111\u01b0\u1ee3c, c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn c\u00e2y b\u1ecb ch\u1ebft. Ti\u1ebft 2 Ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng * M\u1ee5c ti\u00eau: T\u1ea1o h\u1ee9ng th\u00fa v\u00e0 kh\u01a1i g\u1ee3i nh\u1eefng hi\u1ec3u bi\u1ebft \u0111\u00e3 c\u00f3 c\u1ee7a HS v\u1ec1 c\u00e1c y\u1ebfu t\u1ed1 c\u1ea7n thi\u1ebft \u0111\u1ec3 c\u00e2y xanh c\u00f3 th\u1ec3 s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n b\u00ecnh th\u01b0\u1eddng, t\u1ef1 t\u1ed5ng h\u1ee3p ch\u1ea5t dinh d\u01b0\u1ee1ng \u0111\u1ec3 nu\u00f4i c\u00e2y. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV cho HS xem h\u00ecnh \u1ea3nh m\u1ed9t c\u00e2y xanh t\u1ed1t \u0111ang \u0111\u01a1m hoa k\u1ebft tr\u00e1i ho\u1eb7c c\u00f3 th\u1ec3 d\u00f9ng ngay c\u00e1c c\u00e2y xanh \u1edf trong khu\u00f4n vi\u00ean tr\u01b0\u1eddng m\u00e0 HS c\u00f3 th\u1ec3 nh\u00ecn th\u1ea5y khi ng\u1ed3i trong l\u1edbp \u0111\u1ec3 t\u1ed5 ch\u1ee9c ho\u1ea1t \u0111\u1ed9ng n\u00e0y. \u2013 GV \u0111\u1eb7t c\u00e2u h\u1ecfi: \u0110\u1ec3 c\u00e2y xanh s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n th\u00ec c\u1ea7n ph\u1ea3i c\u00f3 nh\u1eefng y\u1ebfu t\u1ed1 n\u00e0o? \u2013 GV m\u1eddi 1 \u2013 2 HS tr\u1ea3 l\u1eddi. G\u1ee3i \u00fd tr\u1ea3 l\u1eddi c\u00e2u h\u1ecfi: C\u00e1c y\u1ebfu t\u1ed1 c\u1ea7n thi\u1ebft l\u00e0 n\u01b0\u1edbc, \u00e1nh s\u00e1ng, kh\u00f4ng kh\u00ed, ch\u1ea5t kho\u00e1ng v\u00e0 nhi\u1ec7t \u0111\u1ed9 th\u00edch h\u1ee3p. \u2013 GV \u0111\u1eb7t th\u00eam c\u00e2u h\u1ecfi: C\u00e1c y\u1ebfu t\u1ed1 c\u1ea7n thi\u1ebft nh\u01b0 n\u01b0\u1edbc, \u00e1nh s\u00e1ng, kh\u00f4ng kh\u00ed, ch\u1ea5t kho\u00e1ng, nhi\u1ec7t \u0111\u1ed9 th\u00edch h\u1ee3p c\u00f3 ph\u1ea3i l\u00e0 th\u1ee9c \u0103n c\u1ee7a c\u00e2y xanh kh\u00f4ng? Th\u1ee9c \u0103n cho c\u00e2y xanh \u0111\u01b0\u1ee3c l\u1ea5y t\u1eeb \u0111\u00e2u? G\u1ee3i \u00fd: C\u00e1c y\u1ebfu t\u1ed1 c\u1ea7n thi\u1ebft cho c\u00e2y xanh: n\u01b0\u1edbc, \u00e1nh s\u00e1ng, nhi\u1ec7t \u0111\u1ed9 th\u00edch h\u1ee3p, ch\u1ea5t kho\u00e1ng kh\u00f4ng ph\u1ea3i l\u00e0 th\u1ee9c \u0103n c\u1ee7a c\u00e2y xanh. Th\u1ee9c \u0103n, ch\u1ea5t dinh d\u01b0\u1ee1ng \u0111\u1ec3 c\u00e2y xanh s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n do c\u00e2y t\u1ef1 t\u1ea1o ra th\u00f4ng qua qu\u00e1 tr\u00ecnh quang h\u1ee3p. \u2013 GV nh\u1eadn x\u00e9t chung v\u00e0 d\u1eabn d\u1eaft v\u00e0o ti\u1ebft 2 c\u1ee7a b\u00e0i h\u1ecdc. Ho\u1ea1t \u0111\u1ed9ng 1: Kh\u00e1m ph\u00e1 s\u1ef1 trao \u0111\u1ed5i kh\u00ed, n\u01b0\u1edbc va\u0300 ch\u1ea5t kho\u00e1ng c\u1ee7a th\u1ef1c v\u1eadt v\u1edbi m\u00f4i tr\u01b0\u1eddng; kha\u0309 na\u0306ng t\u1ef1 t\u00f4\u0309ng h\u01a1\u0323p ch\u00e2\u0301t dinh du\u031b\u01a1\u0303ng c\u1ea7n cho s\u1ef1 s\u1ed1ng c\u1ee7a th\u1ef1c v\u1eadt * M\u1ee5c ti\u00eau: HS tri\u0300nh ba\u0300y \u0111u\u031b\u01a1\u0323c th\u01b0\u0323c v\u1ea1\u0302t co\u0301 kha\u0309 na\u0306ng t\u01b0\u0323 t\u00f4\u0309ng h\u01a1\u0323p ch\u00e2\u0301t dinh du\u031b\u01a1\u0303ng c\u00e2\u0300n cho s\u01b0\u0323 s\u00f4\u0301ng th\u00f4ng qua s\u01a1 \u0111\u1ed3 \u0111\u01a1n gi\u1ea3n. HS hi\u1ec3u v\u00e0 ve\u0303 \u0111u\u031b\u01a1\u0323c so\u031b \u0111\u00f4\u0300 \u0111o\u031bn gia\u0309n (ho\u1ea1\u0306c \u0111i\u00ea\u0300n va\u0300o so\u031b \u0111\u00f4\u0300 cho tru\u031b\u01a1\u0301c) v\u00ea\u0300 s\u01b0\u0323 trao \u0111\u00f4\u0309i khi\u0301, nu\u031b\u01a1\u0301c, ch\u00e2\u0301t khoa\u0301ng cu\u0309a th\u01b0\u0323c v\u1ea1\u0302t v\u01a1\u0301i mo\u0302i tru\u031b\u01a1\u0300ng. 96","* C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV t\u1ed5 ch\u1ee9c cho HS l\u00e0m vi\u1ec7c nh\u00f3m \u0111\u00f4i, y\u00eau c\u1ea7u HS quan s\u00e1t h\u00ecnh 8 (SGK, trang 61), \u0111\u1ecdc th\u00f4ng tin trong h\u00ecnh v\u1ebd v\u00e0 tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: + Trong quang h\u1ee3p, c\u00e2y xanh l\u1ea5y v\u00e0o, th\u1ea3i ra kh\u00ed g\u00ec? S\u1ef1 trao \u0111\u1ed5i kh\u00ed \u1edf h\u00f4 h\u1ea5p kh\u00e1c g\u00ec v\u1edbi s\u1ef1 trao \u0111\u1ed5i kh\u00ed \u1edf quang h\u1ee3p? + C\u00e2y xanh l\u1ea5y n\u01b0\u1edbc v\u00e0 ch\u1ea5t kho\u00e1ng nh\u1edd b\u1ed9 ph\u1eadn n\u00e0o? Th\u00e2n v\u00e0 l\u00e1 \u0111\u00f3ng vai tr\u00f2 g\u00ec trong s\u1ef1 trao \u0111\u1ed5i n\u01b0\u1edbc v\u00e0 ch\u1ea5t kho\u00e1ng \u1edf c\u00e2y xanh? + C\u00e2y xanh t\u1ef1 t\u1ed5ng h\u1ee3p ch\u1ea5t dinh d\u01b0\u1ee1ng nh\u1edd nh\u1eefng y\u1ebfu t\u1ed1 n\u00e0o? S\u1ef1 t\u1ed5ng h\u1ee3p ch\u1ea5t dinh d\u01b0\u1ee1ng \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n \u1edf b\u1ed9 ph\u1eadn n\u00e0o c\u1ee7a c\u00e2y xanh? Qu\u00e1 tr\u00ecnh n\u00e0y go\u0323i l\u00e0 g\u00ec? G\u1ee3i \u00fd: + Trong quang h\u1ee3p, c\u00e2y xanh l\u1ea5y v\u00e0o kh\u00ed c\u00e1c-b\u00f4-n\u00edc, th\u1ea3i ra kh\u00ed \u00f4-xi. S\u1ef1 trao \u0111\u1ed5i kh\u00ed \u1edf h\u00f4 h\u1ea5p kh\u00e1c v\u1edbi s\u1ef1 trao \u0111\u1ed5i kh\u00ed \u1edf quang h\u1ee3p \u1edf ch\u1ed7: c\u00e2y l\u1ea5y v\u00e0o kh\u00ed \u00f4-xi, th\u1ea3i ra kh\u00ed c\u00e1c-b\u00f4-n\u00edc. + C\u00e2y xanh l\u1ea5y n\u01b0\u1edbc v\u00e0 ch\u1ea5t kho\u00e1ng nh\u1edd r\u1ec5.Th\u00e2n gi\u00fap c\u00e2y v\u1eadn chuy\u1ec3n n\u01b0\u1edbc v\u00e0 ch\u1ea5t kho\u00e1ng l\u00ean c\u00e1c b\u1ed9 ph\u1eadn ph\u00eda tr\u00ean c\u1ee7a c\u00e2y xanh. Nh\u1edd \u0111\u00f3, l\u00e1 c\u00f3 n\u01b0\u1edbc \u0111\u1ec3 th\u1ef1c hi\u1ec7n quang h\u1ee3p t\u1ea1o ra ch\u1ea5t dinh d\u01b0\u1ee1ng nu\u00f4i c\u00e2y. M\u1ed9t ph\u1ea7n n\u01b0\u1edbc \u0111\u01b0\u1ee3c tho\u00e1t ra ngo\u00e0i d\u01b0\u1edbi d\u1ea1ng h\u01a1i n\u01b0\u1edbc qua l\u00e1. + C\u00e2y xanh t\u1ef1 t\u1ed5ng h\u1ee3p ch\u1ea5t dinh d\u01b0\u1ee1ng t\u1eeb n\u01b0\u1edbc v\u00e0 kh\u00ed c\u00e1c-b\u00f4-n\u00edc d\u01b0\u1edbi t\u00e1c d\u1ee5ng c\u1ee7a n\u0103ng l\u01b0\u1ee3ng \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi th\u00f4ng qua qu\u00e1 tr\u00ecnh quang h\u1ee3p. S\u1ef1 t\u1ed5ng h\u1ee3p ch\u1ea5t dinh d\u01b0\u1ee1ng \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n \u1edf l\u00e1. Qu\u00e1 tr\u00ecnh n\u00e0y go\u0323i l\u00e0 qu\u00e1 tr\u00ecnh quang h\u1ee3p. + Ngo\u00e0i ch\u1ea5t dinh d\u01b0\u1ee1ng, qu\u00e1 tr\u00ecnh quang h\u1ee3p \u1edf l\u00e1 c\u00f2n t\u1ea1o ra kh\u00ed \u00f4-xi. S\u1ef1 trao \u0111\u1ed5i kh\u00ed n\u00e0y tr\u00e1i ng\u01b0\u1ee3c so v\u1edbi qu\u00e1 tr\u00ecnh h\u00f4 h\u1ea5p \u1edf c\u00e2y xanh. \u1ede h\u00f4 h\u1ea5p, c\u00e2y h\u1ea5p th\u1ee5 kh\u00ed \u00f4-xi, th\u1ea3i ra kh\u00ed c\u00e1c-b\u00f4-n\u00edc c\u00f2n \u1edf qu\u00e1 tr\u00ecnh quang h\u1ee3p th\u00ec c\u00e2y h\u1ea5p th\u1ee5 kh\u00ed c\u00e1c-b\u00f4-n\u00edc, th\u1ea3i ra kh\u00ed \u00f4-xi. \u2013 GV m\u1eddi m\u1ed9t s\u1ed1 HS tr\u1ea3 l\u1eddi l\u1ea7n l\u01b0\u1ee3t c\u00e1c c\u00e2u h\u1ecfi \u0111\u01b0\u1ee3c g\u1ee3i \u00fd trong SGK \u0111\u1ec3 gi\u00fap HS kh\u00e1m ph\u00e1 ki\u1ebfn th\u1ee9c. GV c\u00f3 th\u1ec3 b\u1ed5 sung th\u00eam m\u1ed9t s\u1ed1 c\u00e2u h\u1ecfi nh\u1ecf \u0111\u1ec3 g\u1ee3i \u00fd cho HS. \u2013 GV v\u00e0 HS c\u00f9ng nh\u1eadn x\u00e9t v\u00e0 r\u00fat ra k\u1ebft lu\u1eadn v\u1ec1 kh\u1ea3 n\u0103ng t\u1ef1 t\u1ed5ng h\u1ee3p ch\u1ea5t dinh d\u01b0\u1ee1ng c\u1ee7a c\u00e2y xanh th\u00f4ng qua qu\u00e1 tr\u00ecnh quang h\u1ee3p, vai tr\u00f2 c\u1ee7a c\u00e1c b\u1ed9 ph\u1eadn ch\u00ednh: l\u00e1, th\u00e2n, r\u1ec5 c\u1ee7a c\u00e2y xanh \u0111\u1ed1i v\u1edbi qu\u00e1 tr\u00ecnh quang h\u1ee3p. * K\u1ebft lu\u1eadn: \u2022\t C\u00e2y c\u00f3 th\u1ec3 t\u1ef1 t\u1ed5ng h\u1ee3p ch\u1ea5t dinh d\u01b0\u1ee1ng c\u1ea7n thi\u1ebft cho s\u1ef1 s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n t\u1eeb kh\u00ed c\u00e1c-b\u00f4-n\u00edc v\u00e0 n\u01b0\u1edbc d\u01b0\u1edbi t\u00e1c d\u1ee5ng c\u1ee7a \u00e1nh s\u00e1ng m\u1eb7t tr\u1eddi th\u00f4ng qua qu\u00e1 tr\u00ecnh quang h\u1ee3p. Qu\u00e1 tr\u00ecnh n\u00e0y th\u1ea3i ra kh\u00ed \u00f4-xi. \u2022\t Trong h\u00f4 h\u1ea5p, c\u00e2y h\u1ea5p th\u1ee5 kh\u00ed \u00f4-xi, th\u1ea3i ra kh\u00ed c\u00e1c-b\u00f4-n\u00edc. \u2022\t N\u01b0\u1edbc v\u00e0 ch\u1ea5t kho\u00e1ng \u0111\u01b0\u1ee3c r\u1ec5 c\u00e2y h\u1ea5p th\u1ee5 v\u00e0 v\u1eadn chuy\u1ec3n l\u00ean ph\u00eda tr\u00ean nh\u1edd th\u00e2n c\u00e2y. M\u1ed9t ph\u1ea7n n\u01b0\u1edbc \u0111\u01b0\u1ee3c v\u1eadn chuy\u1ec3n t\u1eeb r\u1ec5 l\u00ean s\u1ebd tho\u00e1t qua l\u00e1 ra ngo\u00e0i kh\u00f4ng kh\u00ed d\u01b0\u1edbi d\u1ea1ng h\u01a1i n\u01b0\u1edbc. 97","Ho\u1ea1t \u0111\u1ed9ng 2: Ho\u00e0n th\u00e0nh s\u01a1 \u0111\u1ed3 \u0111\u01a1n gi\u1ea3n m\u00f4 t\u1ea3 qu\u00e1 tr\u00ecnh quang h\u1ee3p \u1edf c\u00e2y xanh * M\u1ee5c ti\u00eau: HS tri\u0300nh ba\u0300y \u0111u\u031b\u01a1\u0323c s\u01a1 \u0111\u1ed3 \u0111\u01a1n gi\u1ea3n bi\u1ec3u di\u1ec5n qu\u00e1 tr\u00ecnh quang h\u1ee3p \u1edf c\u00e2y xanh. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV y\u00eau c\u1ea7u HS quan s\u00e1t h\u00ecnh 8 (SGK, trang 61), v\u1eadn d\u1ee5ng ki\u1ebfn th\u1ee9c \u0111\u00e3 \u0111\u01b0\u1ee3c kh\u00e1m ph\u00e1 \u1edf ho\u1ea1t \u0111\u1ed9ng 1 c\u1ee7a ti\u1ebft 2 \u0111\u1ec3 \u0111i\u1ec1n th\u00f4ng tin ph\u00f9 h\u1ee3p v\u00e0o c\u00e1c ch\u1ed7 c\u00f3 d\u1ea5u \u201c?\u201d. \u2013 HS quan s\u00e1t h\u00ecnh, v\u1eadn d\u1ee5ng ki\u1ebfn th\u1ee9c \u0111\u1ec3 th\u1ef1c hi\u1ec7n y\u00eau c\u1ea7u c\u1ee7a GV. \u2013 GV m\u1eddi 2 \u2013 3 HS tr\u00ecnh b\u00e0y \u00fd ki\u1ebfn v\u00e0 chia s\u1ebb v\u1edbi l\u1edbp. GV c\u00f3 th\u1ec3 y\u00eau c\u1ea7u HS vi\u1ebft l\u00ean b\u1ea3ng ho\u1eb7c vi\u1ebft v\u00e0o v\u1edf. \u2013 GV nh\u1eadn x\u00e9t v\u00e0 t\u1ed5ng k\u1ebft v\u1edbi to\u00e0n l\u1edbp. G\u1ee3i \u00fd: Kh\u00ed c\u00e1c-b\u00f4-n\u00edc Th\u1ef1c v\u1eadt Kh\u00ed \u00f4-xi N\u01b0\u1edbc Ch\u1ea5t dinh d\u01b0\u1ee1ng Ho\u1ea1t \u0111\u1ed9ng ti\u1ebfp n\u1ed1i sau b\u00e0i h\u1ecdc GV y\u00eau c\u1ea7u HS v\u1ec1 nh\u00e0 x\u00e9 d\u00e1n \u0111\u1ec3 l\u00e0m m\u00f4 h\u00ecnh bi\u1ec3u di\u1ec5n qu\u00e1 tr\u00ecnh trao \u0111\u1ed5i ch\u1ea5t \u1edf l\u00e1 th\u00f4ng qua qu\u00e1 tr\u00ecnh quang h\u1ee3p. Ti\u1ebft 3 Ho\u1ea1t \u0111\u1ed9ng kh\u1edfi \u0111\u1ed9ng * M\u1ee5c ti\u00eau: T\u1ea1o h\u1ee9ng th\u00fa v\u00e0 nh\u1eafc l\u1ea1i nh\u1eefng hi\u1ec3u bi\u1ebft \u0111\u00e3 c\u00f3 c\u1ee7a HS \u1edf hai ti\u1ebft h\u1ecdc tr\u01b0\u1edbc v\u1ec1 c\u00e1c y\u1ebfu t\u1ed1 c\u1ea7n thi\u1ebft \u0111\u1ec3 c\u00e2y xanh c\u00f3 th\u1ec3 s\u1ed1ng v\u00e0 ph\u00e1t tri\u1ec3n b\u00ecnh th\u01b0\u1eddng, v\u1ec1 qu\u00e1 tr\u00ecnh t\u1ef1 t\u1ed5ng h\u1ee3p ch\u1ea5t dinh d\u01b0\u1ee1ng \u0111\u1ec3 nu\u00f4i c\u00e2y. T\u1eeb \u0111\u00f3 d\u1eabn d\u1eaft v\u00e0o ti\u1ebft h\u1ecdc m\u1edbi. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV t\u1ed5 ch\u1ee9c cho HS thi \u0111ua tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi: + Trong qu\u00e1 tr\u00ecnh quang h\u1ee3p, c\u00e2y xanh h\u1ea5p thu kh\u00ed g\u00ec v\u00e0 th\u1ea3i ra kh\u00ed g\u00ec? + N\u01b0\u1edbc \u0111\u01b0\u1ee3c l\u00e1 c\u00e2y s\u1eed d\u1ee5ng trong quang h\u1ee3p l\u1ea5y t\u1eeb \u0111\u00e2u v\u00e0 nh\u1edd b\u1ed9 ph\u1eadn n\u00e0o c\u1ee7a c\u00e2y \u0111\u1ec3 n\u01b0\u1edbc c\u00f3 \u1edf l\u00e1? \u2013 HS v\u1eadn d\u1ee5ng ki\u1ebfn th\u1ee9c \u0111\u00e3 h\u1ecdc \u1edf c\u00e1c ti\u1ebft tr\u01b0\u1edbc \u0111\u1ec3 tr\u1ea3 l\u1eddi. G\u1ee3i \u00fd: + Trong qu\u00e1 tr\u00ecnh quang h\u1ee3p, c\u00e2y xanh h\u1ea5p thu kh\u00ed c\u00e1c-b\u00f4-n\u00edc, th\u1ea3i ra kh\u00ed \u00f4-xi. + N\u01b0\u1edbc m\u00e0 l\u00e1 c\u00e2y s\u1eed d\u1ee5ng trong quang h\u1ee3p \u0111\u01b0\u1ee3c l\u1ea5y t\u1eeb \u0111\u1ea5t th\u00f4ng qua r\u1ec5 c\u00e2y v\u00e0 \u0111\u01b0\u1ee3c th\u00e2n c\u00e2y v\u1eadn chuy\u1ec3n l\u00ean l\u00e1 ph\u1ee5c v\u1ee5 cho qu\u00e1 tr\u00ecnh quang h\u1ee3p. \u2013 GV nh\u1eadn x\u00e9t c\u00e2u tr\u1ea3 l\u1eddi c\u1ee7a HS v\u00e0 d\u1eabn d\u1eaft v\u00e0o ti\u1ebft 3 c\u1ee7a b\u00e0i h\u1ecdc. 98","Ho\u1ea1t \u0111\u1ed9ng 1: Tr\u00f2 ch\u01a1i \u201cAi \u0111\u00fang, ai nhanh?\u201d * M\u1ee5c ti\u00eau: HS hi\u1ec3u v\u00e0 v\u1eadn d\u1ee5ng \u0111\u01b0\u1ee3c ki\u1ebfn th\u1ee9c \u0111\u00e3 h\u1ecdc \u0111\u1ec3 \u0111i\u00ea\u0300n (ho\u1eb7c g\u1eafn th\u1ebb ch\u1eef) va\u0300o so\u031b \u0111\u00f4\u0300 cho tru\u031b\u01a1\u0301c v\u00ea\u0300 s\u01b0\u0323 trao \u0111\u00f4\u0309i khi\u0301, nu\u031b\u01a1\u0301c, ch\u00e2\u0301t khoa\u0301ng cu\u0309a th\u01b0\u0323c v\u1ea1\u0302t v\u01a1\u0301i mo\u0302i tru\u031b\u01a1\u0300ng. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 4, ph\u00e1t cho m\u1ed7i nh\u00f3m c\u00e1c th\u1ebb ch\u1eef v\u00e0 m\u1ed9t t\u1edd gi\u1ea5y A4 c\u00f3 in h\u00ecnh s\u01a1 \u0111\u1ed3 nh\u01b0 m\u00f4 t\u1ea3 \u1edf h\u00ecnh 9 (SGK, trang 62). M\u1ed7i nh\u00f3m c\u00f3 th\u1eddi gian 5 ph\u00fat \u0111\u1ec3 suy ngh\u0129 v\u00e0 ho\u00e0n thi\u1ec7n vi\u1ec7c gh\u00e9p c\u00e1c th\u1ebb ch\u1eef v\u00e0o nh\u1eefng v\u1ecb tr\u00ed c\u00f3 d\u1ea5u ch\u1ea5m h\u1ecfi tr\u00ean s\u01a1 \u0111\u1ed3 sao cho ph\u00f9 h\u1ee3p. Nh\u00f3m n\u00e0o gh\u00e9p \u0111\u00fang v\u00e0 nhanh nh\u1ea5t s\u1ebd \u0111\u01b0\u1ee3c tuy\u00ean d\u01b0\u01a1ng. \u2013 GV theo d\u00f5i th\u1eddi gian v\u00e0 h\u00f4 k\u1ebft th\u00fac sau khi h\u1ebft th\u1eddi gian 5 ph\u00fat. GV m\u1eddi c\u00e1c nh\u00f3m l\u00e0m sai l\u00ean tr\u00ecnh b\u00e0y tr\u01b0\u1edbc, nh\u00f3m l\u00e0m \u0111\u00fang tr\u00ecnh b\u00e0y sau c\u00f9ng. \u2013 GV theo d\u00f5i, \u0111i\u1ec1u khi\u1ec3n qu\u00e1 tr\u00ecnh chia s\u1ebb c\u1ee7a c\u00e1c nh\u00f3m. \u2013 HS tr\u1ea3 l\u1eddi v\u00e0 nh\u1eadn x\u00e9t l\u1eabn nhau. \u2013 GV v\u00e0 HS c\u00f9ng nhau nh\u1eadn x\u00e9t, r\u00fat ra k\u1ebft lu\u1eadn v\u1ec1 s\u01a1 \u0111\u1ed3 \u0111\u00fang. G\u1ee3i \u00fd: (a): n\u01b0\u1edbc; (b): v\u1eadn chuy\u1ec3n n\u01b0\u1edbc v\u00e0 ch\u1ea5t kho\u00e1ng; (c): kh\u00ed c\u00e1c-b\u00f4-n\u00edc; (d): kh\u00ed \u00f4-xi; (e): h\u01a1i n\u01b0\u1edbc; (g): ch\u1ea5t dinh d\u01b0\u1ee1ng; (h): ch\u1ea5t kho\u00e1ng. L\u01b0u \u00fd: n\u1ebfu HS \u0111i\u1ec1n (d): h\u01a1i n\u01b0\u1edbc v\u00e0 (e): kh\u00ed \u00f4-xi c\u0169ng \u0111\u00fang. Ho\u1ea1t \u0111\u1ed9ng 2: Em t\u1eadp l\u00e0m nh\u00e0 khoa h\u1ecdc: Th\u00ed nghi\u1ec7m \u201cL\u00e1 c\u00f3 tho\u00e1t h\u01a1i n\u01b0\u1edbc kh\u00f4ng?\u201d * M\u1ee5c ti\u00eau: HS hi\u1ec3u v\u00e0 ch\u1ee9ng minh \u0111\u01b0\u1ee3c m\u1ed9t ph\u1ea7n n\u01b0\u1edbc tho\u00e1t ra t\u1eeb l\u00e1 d\u01b0\u1edbi d\u1ea1ng h\u01a1i n\u01b0\u1edbc. * C\u00e1ch ti\u1ebfn h\u00e0nh: \u2013 GV c\u1ea7n chu\u1ea9n b\u1ecb th\u00ed nghi\u1ec7m tr\u01b0\u1edbc khi ti\u1ebft h\u1ecdc b\u1eaft \u0111\u1ea7u kho\u1ea3ng ba ti\u1ebfng, l\u00e0m theo h\u01b0\u1edbng d\u1eabn trong SGK. GV n\u00ean cho HS c\u00f9ng tham gia chu\u1ea9n b\u1ecb th\u00ed nghi\u1ec7m. L\u01b0u \u00fd: \u0110\u1ec3 \u0111\u1ea3m b\u1ea3o th\u00ed nghi\u1ec7m \u0111\u01b0\u1ee3c th\u00e0nh c\u00f4ng, th\u1eddi gian chu\u1ea9n b\u1ecb c\u00f3 th\u1ec3 k\u00e9o d\u00e0i h\u01a1n trong tr\u01b0\u1eddng h\u1ee3p th\u1eddi ti\u1ebft c\u00f3 m\u01b0a, l\u1ea1nh. GV c\u00f3 th\u1ec3 cho m\u1ed7i nh\u00f3m th\u1ef1c hi\u1ec7n tr\u00ean m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng c\u00e2y kh\u00e1c nhau cho phong ph\u00fa v\u00e0 ch\u1ee9ng minh cho HS th\u1ea5y r\u00f5 v\u1ea5n \u0111\u1ec1. \u2013 GV chia l\u1edbp th\u00e0nh c\u00e1c nh\u00f3m 6, y\u00eau c\u1ea7u HS quan s\u00e1t b\u00ean trong t\u00fai ni l\u00f4ng nh\u1ecf v\u00e0 l\u1edbn, th\u1ea3o lu\u1eadn nh\u00f3m v\u00e0 tr\u1ea3 l\u1eddi c\u00e2u h\u1ecfi: Em th\u1ea5y c\u00f3 hi\u1ec7n t\u01b0\u1ee3ng g\u00ec b\u00ean trong t\u00fai ni-l\u00f4ng nh\u1ecf v\u00e0 l\u1edbn? \u2013 HS quan s\u00e1t, tr\u1ea3 l\u1eddi. \u2013 GV y\u00eau c\u1ea7u HS gi\u1ea3i th\u00edch hi\u1ec7n t\u01b0\u1ee3ng quan s\u00e1t \u0111\u01b0\u1ee3c. GV c\u00f3 th\u1ec3 \u0111\u1eb7t c\u00e1c c\u00e2u h\u1ecfi g\u1ee3i \u00fd: V\u00ec sao c\u00f3 h\u01a1i n\u01b0\u1edbc trong t\u00fai ni l\u00f4ng nh\u1ecf? H\u01a1i n\u01b0\u1edbc trong t\u00fai ni l\u00f4ng l\u1edbn do \u0111\u00e2u m\u00e0 c\u00f3? V\u00ec sao th\u00ed nghi\u1ec7m n\u00e0y c\u1ea7n d\u00f9ng 2 t\u00fai ni l\u00f4ng? \u2013 GV m\u1eddi 2 \u2013 3 HS gi\u1ea3i th\u00edch, c\u00e1c HS kh\u00e1c nh\u1eadn x\u00e9t v\u00e0 b\u1ed5 sung. G\u1ee3i \u00fd: + Em quan s\u00e1t th\u1ea5y c\u00f3 n\u01b0\u1edbc trong t\u00fai ni l\u00f4ng nh\u1ecf v\u00e0 t\u00fai ni l\u00f4ng l\u1edbn. + Gi\u1ea3i th\u00edch: N\u01b0\u1edbc trong t\u00fai ni l\u00f4ng nh\u1ecf l\u00e0 do h\u01a1i n\u01b0\u1edbc t\u1eeb \u0111\u1ea5t c\u1ee7a ch\u1eadu c\u00e2y bay h\u01a1i l\u00ean, ng\u01b0ng t\u1ee5 \u1edf t\u00fai ni l\u00f4ng \u0111\u01b0\u1ee3c bu\u1ed9c t\u00fam ph\u1ee7 ch\u1eadu tr\u1ed3ng c\u00e2y. N\u01b0\u1edbc trong t\u00fai ni l\u00f4ng l\u1edbn l\u00e0 do h\u01a1i n\u01b0\u1edbc tho\u00e1t ra t\u1eeb l\u00e1 c\u00e2y ng\u01b0ng t\u1ee5 l\u1ea1i tr\u00ean t\u00fai ni l\u00f4ng \u0111\u01b0\u1ee3c tr\u00f9m ph\u1ee7 to\u00e0n b\u1ed9 c\u00e2y. + Th\u00ed nghi\u1ec7m d\u00f9ng 2 t\u00fai ni l\u00f4ng \u0111\u1ec3 c\u00f3 th\u1ec3 ph\u00e2n bi\u1ec7t h\u01a1i n\u01b0\u1edbc t\u1eeb \u0111\u1ea5t trong ch\u1eadu c\u00e2y bay l\u00ean ng\u01b0ng t\u1ee5 v\u00e0 h\u01a1i n\u01b0\u1edbc tho\u00e1t ra t\u1eeb l\u00e1 c\u00e2y nh\u01b0 l\u00ed thuy\u1ebft \u0111\u00e3 \u0111\u01b0\u1ee3c h\u1ecdc \u1edf ti\u1ebft 2. 99"]