InvisibleForces_magazine

Contents What forces do you see? . . . . . . . . . . . . . . . . 2 What is static electricity? . . . . . . . . . . . . . . . . 4 How can you stay safe in a thunderstorm? . . . . . . . 6 How do conditions affect static electricity? . . . . . . . 8 How does Static Stan avoid the static? . . . . . . . . . 1100 Where can you find magnets? . . . . . . . . . . . . . . . 1122 Which objects are attracted to magnets? . . . . . . . . 144 Which materials can be magnetized? . . . . . . . . . . 116

Note: The terms in red text can be found in the Glossary on page 32. How can you test the strength of a magnet? . . . . . . .18 What is a magnetic field? . . . . . . . . . . . . . . . 220 How does a compass work? . . . . . . . . . . . . . . 22 How do animals use the Earth’s magnetic field? . . . . 224 How can invisible forces affect you? . . . . . . . . . . 226 How do toys and games use invisible forces? . . . . . 228 What else can you make using invisible forces? . . . . 3300 Glossary . . . . . . . . . . . . . . . . . . . . . . . . 332

What forces do you see? A force is a push or a pull. Some forces act when materials are touching. Forces that can affect objects without touching them are called invisible forces.You can’t see them but you can see their effects. 2

? How many examples of forces can you find in this carnival scene? Can you find an example of an invisible force? 3

What is static Static electricity isn’t scary, but it can make your hair stand on end! Have you ever pulled off your hat and found that your hair was sticking straight up? Blame static electricity. Static electricity is the buildup of an electrostatic charge on the surface of an object. It is called static electricity because the charge stays in one place. Did You Know? Most of the time, objects have a neutral charge (positive People get a charge charges and negative charges out of a Van de Graaff are balanced). But when generator! These materials are rubbed together, generators can be the charges become unbalanced used to create static and result in a static charge. electricity and small versions are found in many science museums. 4

electricity? Objects with different or Uncharged, or neutral, balloons opposite static charges have no interaction. (positive and negative) will attract or pull toward each What might happen if other. one or both balloons are rubbed with a Objects with the same different material? charge will repel or push away from each other. Why do you think your hair stood up when you pulled off your hat? How did static electricity cause this to happen? STATIC ELECTRICITY What is it? How does it Example work? a buildup of When objects When you dry clothes in the electrostatic made from dryer, different fabrics rub charge different materials together, and electrostatic are rubbed charges build up. Nylon socks together, opposite (for example) may rub against static charges a polyester blanket.The socks build up on the and the blanket gain opposite surfaces of the charges that attract each objects. other so they stick together. 5

How can you stay safe Lightning is a bright flash of electricity produced by a thunderstorm. When charges build up, lightning strikes. Remember – if you can hear thunder, you are within striking distance of lightning! Take a look at each action and decide which you should and should not do during a thunderstorm. Explain your reasoning to a partner. 6

in a thunderstorm? Did You Know? Stay Safe! When you are inside Stay inside for 30 minutes after during a thunderstorm the last rumble of thunder you should avoid before going outside. plumbing, including sinks, baths, and water faucets. If lightning strikes your house or nearby, the lightning charge may travel through the pipes and you could be hurt. 7

How do conditions affect Mars is an icy-cold planet covered in reddish dust and dirt. The soil on Mars is thought to be very dry—drier than desert sand on Earth! If humans ever make it to the red planet, static electricity will be a very real threat. Without moisture to lessen the effects of static electricity, astronauts could face little lightning bolts every time they touch anything after walking around on Mars’ soil. Blasting off in 2020, the Mars 2020 rover will be rolling over the Martian landscape exploring the rocks, dirt, and air. Over time, the dry soil will cling to the rover’s wheels and may result in a static discharge that could disrupt the electronics of the machine. Conditions in space can also cause a buildup of static electricity! This could be dangerous for an astronaut who touches the surface of the International Space Station (ISS) during a spacewalk. The ISS has a device that can lessen this buildup of static electricity and can be used by astronauts during spacewalks to lower the 8 level of danger.

static electricity? What conditions on Earth help keep static electricity from building up to the dangerous levels found on Mars? 9

How does Static Stan avoid 10

Static Stan also knows when forces are helpful! static?the electrostatic 11

Where can you find magnets? Magnets can be found in many A magnetic strip keeps the of the objects you use and see around you. A magnet on a can refrigerator door closed, and small opener holds the lid when it is fridge magnets make fun vacation cut from the can, magnets hold keepsakes. a shower curtain tight to the surface of the bathtub to stop Magnets make water leaks during your shower, it easy to use and magnets are sometimes used just one hand to keep cupboard doors closed. to put on and take off Take a look at the jewellery such pictures to see where as a bracelet. else magnets are commonly used. Magnets can keep a purse A magnetic tip on firmly closed. a screwdriver holds Paper clips are 12 the screw in place. kept organized by a magnet.

Maglev (short for “magnetic levitation”) trains use strong magnets to make the train float above the track. This allows the train to travel at very high speeds. Metal kitchen tools are kept tidy and within easy reach with a magnetic strip. Scrapyards use huge magnets to separate items made of metal. An alarm will sound if an Did You Know? item with an attached magnetic security tag is Magnetic nail polish can removed from a store. be used to create designs. Tiny bits of magnetic metal in the polish respond to a 13 magnet in the bottle lid to form shapes on the surface of the painted nail.

Which objects are attracted magnets? to Objects that are attracted to magnets are magnetic. Predict which of the objects shown are magnetic. How will you test the objects? What other objects would you like to test? 14

What do all of the objects attracted to magnets have in common? 15

Wmhaichgmnaetteriizaelsdca?n be Metal objects are attracted to magnets, but can all metal objects be magnetized? Predict which of these metal objects can be magnetized, then test to find out. When an object is magnetized, it is made to act as a magnet. The magnetic force for one of these magnets isn’t very strong, and its ability to attract or repel other objects doesn’t last very long. This is why it is known as a temporary magnet. 16

Make Your Own Magnet 1. Drag a magnet down the length of an object 20 times. Be sure to drag in the same direction each time. 2. Test to find out if the object has been magnetized. Will it pick up a number of loose staples? 3. Record the number of staples that were picked up by the magnetized object. Did You Know? Magnetite is a mineral that is found in several places around the world. It is strongly attracted to magnets. Some forms of magnetite, commonly known as lodestone, are actually natural permanent magnets. 17

How can you test the strength of a magnet? There are many ways to test the strength of a magnet. This test uses a toy car, a magnetic object, a magnet, and a ruler. How do you think this test works? What will be measured? How can this tell you how strong a magnet is? bar magnet 18

toy car magnetic object bar magnet graph paper ruler How could you test the strength of other types of magnets? What other ways could you test the strength of a magnet? 19

What is a magnetic field? A magnet can attract objects Can you predict where or repel them without actually the magnetic force is touching them. This happens the strongest? because magnets have a magnetic field all around them. A magnetic field is the space around a magnet where its magnetic force acts. For all magnets, the magnetic field is strongest near its poles and gets weaker further away. Magnetic objects must be inside the magnetic field to be affected by a magnet. The magnetic field is invisible, but you can see it by sprinkling iron filings near a magnet. What might the magnetic field look like for a different type of magnet? 20

When you place two magnets together, they attract or repel each other. The north pole of one magnet will attract the south pole of a second magnet, but repel its north pole. Opposite poles attract. Like poles repel. When two bar magnets are placed near each other, you can see the attraction between the opposite poles. S NS N When two bar magnets are placed near each other, you can see the repulsion between the like poles. S NN S See the Magnetic Field What does the magnetic field look like for attraction? 1. Place two bar magnets What does the magnetic field end-to-end on a paper look like for repulsion? plate. 21 2. Sprinkle iron filings over and around both bar magnets.

a cHoomwpadsosewsork? Compasses The Earth is a giant magnet! find me very The nickel and iron core of the attractive! Earth gives it a magnetic field much like a bar magnet. And like all magnets, Earth has a north pole and a south pole which are found near the geographic North and South Poles. Earth’s magnetic poles attract smaller magnets, so the magnetic needle in a compass will always point to Earth’s north magnetic pole. 22

A compass helps Did You Know? you find directions. When you know which direction is north, you can find south, east, and west. Your compass wouldn’t Fantastic light shows take work on the moon, place in the sky over the however. The moon doesn’t North Pole of our planet. have as much iron as Earth, These Northern Lights, so it is not a magnet. also known as the aurora borealis, are caused by solar wind from the sun interacting with Earth’s magnetic field. These lights are often green but may also be other colours such as blue or red. A light show appears at the South Pole as well. The Southern Lights are called the aurora australis. 23

EHaorwthdo’samnaimganelstuicse the field? Animals don’t use a compass monarch butterfly to find their way. And it isn’t magic! Some animals can sense Earth’s magnetic field, and it is this ability that helps them to navigate between their winter and summer homes. humpback whale spiny lobster 24

little brown bat honeybees peregrine falcon salmon leatherback turtle earthworms 25

How can invisible forces affect You? Finish Make the most of invisible forces by climbing the ladders and avoiding the slides! 1 Play with a partner. You zoom down a slide and your hair 2 Choose a game piece (e.g., a button, coin). stands on end! 3 Take turns rolling a die It’s so humid that the Your little brother lost and moving your piece. cling wrap won’t stick your compass but that’s to your bowl of lunch okay because you know 4 The first one to reach the Finish wins! leftovers. how to make one. The air purifier in your house uses static electricity to filter dust and pollen from the air. You’ve made a cool You walk on the magnetic photo carpet in your socks, then you touch the frame to display your doorknob and ZAP! latest work of art. Start Time to clean your room—the electrostatic 26 charge in your duster makes getting rid of dust a breeze!

You dropped your temporary magnet and it lost its magnetic force. Your dad forgets to put an anti-static sheet in the dryer and all your clothes stick together. You amaze your Oops. You lost one of friends by making a the magnets to hold charged balloon bend your earring in place. a stream of water. 27 Ouch! Your skin gets The magnetic tip on caught when two the screwdriver means strong magnets your mom will never attract. drop another screw. You hear thunder Uh oh, a strong and immediately go magnet is accidentally inside to stay safe placed next to your from lightning. computer. Your new bracelet has a magnetic closure so it’s a snap to put on and take off.

How do toys and games use invisible forces? Many toys and games involve invisible forces. They use attraction or repulsion to work. Use the magnetic pen to pull black magnetic particles to the surface of the board to create your drawing. Then erase it by pulling the slide across the screen to drag the particles away from the surface. The magnetic tips on these Magnetic letters darts are attracted to the are attracted to any magnetic 28 metal dartboard. surface such as your refrigerator or a magnetic board.

Magnets keep these train cars running together down the track. These magnetic beads are attracted to each other and can be formed into many different sculpture shapes. Hook the magnetic animals Building is a in this fishing game. breeze with magnetic Create different squares and fashions for triangles. these dolls using the pieces of magnetic clothing. A magnetic game board Construct any number keeps the game pieces in of shapes using these place and is perfect for magnetic pieces. when you’re on the go. Magnetic pieces make fun and interesting sculptures. 29

What else can you make You know that some toys and games use attraction or repulsion to work. What other fun and helpful items can you make that use invisible forces? Here are a few ideas: Organize: • Small magnetic containers can hold your stuff. • Organize Lego people by putting magnets on the base pieces and then connecting the characters to the base pieces. • Store toys such as small cars on a magnetic strip by attaching thin magnets to the bottoms of the cars. <photoshoot to come> 30

using invisible forces? Display: • Mini-frame fridge magnets display photos and artwork. Decorate: 31 • D ecorations for your room can be attached by magnets to curtains or a lampshade (a magnet is placed on the other side to hold the decoration in place). What else could you make that uses invisible forces?

Glossary attract: to pull toward each other compass: a tool with a magnetic needle that always points toward Earth’s north magnetic pole; can help you find a direction echleacrtgroe:static a charge on the surface of a material that lets it attract or repel other materials force: a push or pull that makes something move, change shape, change direction, or stop moving magnet: a natural or human-made object that attracts matter that contains iron, steel, nickel, or cobalt magnetic: attracted by a magnet magnetic the area around a magnet where its magnetic force acts field: magnetize: to make an object that contains iron, steel, nickel, or cobalt act like a magnet neutral balance of negative and positive charges charge: north pole: the north end of a magnet where the magnetic force is very strong repel: to push apart south pole: the south end of a magnet where the magnetic force is very strong static a buildup of charged particles electricity: 32

Answers for back cover What did one magnet say to the other magnet? Where do you Answer grow a magnet? I’m attracted to you. Answer How did the scientist In a magnetic field. pay for her magnets? Answer Why did the lightning go to She charged the doctor? them! Answer How did the balloon feel about losing its electrical charge? Because it had no spark. Answer It was ex-static. Grade 3: Unit 3: Invisible Forces Magazine Copyright © 2018 Scholastic Canada Ltd. 175 Hillmount Road, Markham, Ontario, Canada L6C 1Z7 Written by Jenny Armstrong Photos ©: cover: Jeffrey Coolidge/Getty Images; cover inset: man with child: Katie Butt; cover inset: three children: Sundus Butt; inside front cover top-1 top left: Ontario Science Centre; inside front cover bottom: Dave Nelson/Shutterstock; 1 top right: Iain McGillivray/Shutterstock; 1 bottom: revers/Shutterstock; 4 top: Photo by Brook Pieman/Getty Images; 4 bottom: Ontario Science Centre; 5 top: GIPhotoStock/Science Source; 5 bottom: Richard Hutchings/Science Source; 6-7 background: FlashMovie/Shutterstock; 8-9 background: Dotted Yeti/Royalty FreeShutterstock; 8 left: JPL- Caltech/NASA; 8 right: 3Dsculptor/Shutterstock; 12 fridge magnets: Andrey Emelyanenko/Shutterstock; 12 bracelet: Deewylin/Dreamstime; 12 bag: Daryna7/Shutterstock; 12 paper clips: Marco Govel/Shutterstock; 12 screws: asu-t1/Shutterstock; 13 train: Christian Petersen-Clausen/Getty Images; 13 giant magnet: BanksPhotos/iStockphoto; 13 utensils: BelkaG/Shutterstock; 13 pants magnet: Bussababum/Shutterstock; 13 nail polish: Bogdan Florea/Shutterstock; 14-15 magnet with nails: revers/Shutterstock; 14 cork: Nik_Merkulov/Thinkstock; 14 washers: Maksim Loskutnikov/ Dreamstime; 14 nuts and bolt: Bsanchezsobrino/Dreamstime; 14 eraser: subjug/iStockphoto; 15 comb: Pixelrobot/Dreamstime; 15 binder clips: Khongkitwiriyachan/Dreamstime; 15 staples: Shariff Che\\’ Lah/Dreamstime; 15 blocks: Diyanski/Dreamstime; 15 packaging foil: Dumrongsak Songdej/Dreamstime; 15 paper clips: Katerinalin/Dreamstime; 15 can: Nevodka/Dreamstime; 16 aluminum foil: Oseland/Dreamstime; 16 brass fastners: Mobi68/Dreamstime; 16 paper clips: Alex Zarubin/Dreamstime; 16 key: Bizhan33/Dreamstime; 16 spoon: Kasinv/Dreamstime; 16 scissors: Viachaslau Bondarau/Dreamstime; 16 coins: Daniel Hussey/Dreamstime; 17 nails: Petro Korchmar/Dreamstime; 17 jar lid: gonzalosilvestre/Thinkstock; 17 hands with magnet: Derek Griffiths for Scholastic Canada Ltd; 17 bottom boy: real444/Getty Images; 17 magnetite: Aleksandr Pobedimskiy/Shutterstock; 18-19 wand magnet and experiment set up: Lorne Chapman for Scholastic Canada Ltd; 18 bottom left: Pictac/Dreamstime; 19 top centre bar magnets: Bildgigant/Shutterstock; 19 top right red and silver magnet: Split Second Stock/Shutterstock; 19 top left red and blue magnet: revers/ Shutterstock; 19 bottom centre ring magnet: Fedorov Oleksiy/Shutterstock; 19 bottom all other magnets: Dannyphoto80/Dreamstime; 20: Cordelia Molloy/Science Source; 23 top right: Pi-Lens/ Shutterstock; 24-25 humpback whale: Martin Prochazkacz/Shutterstock; 24 monarch butterfly: Dave Nelson/Shutterstock; 24 spiny lobster: Christopher Poe/Shutterstock; 25 little brown bat: Igor Cheri/Shutterstock; 25 salmon: Aristokrates/Shutterstock; 25 honeybees: Mircea Costina/Shutterstock; 25 leatherback turtle: Scubazoo/Alamy Images; 25 peregrine falcon: Chris Hill/Shutterstock; 25 earthworms: Nataly Studio/Shutterstock; 26 boy: Robert Anton Iuhas/Alamy Images; 26 duster: Bohuslav Jelen/Dreamstime; 27 balloon: Charles D. Winters/Science Source; 27 dryer sheets: Lorne Chapman for Scholastic Canada Ltd; 27 magnet: revers/Shutterstock; 27 bracelet: Deewylin/Dreamstime; 28 magnetic drawing board: Alexey Petrunin/Dreamstime; 28 darts: Aleksandr Lobanov/ Dreamstime; 28 whiteboard: Gert Lavsen/Dreamstime; 28 magnetic letters: Plus69/Dreamstime; 29 toy train: Tomasz Wieja/Dreamstime; 29 magnetic beads: Dmitrii Kiselev/Dreamstime; 29 fishing game: Pamela Uyttendaele/Shutterstock; 29 dolls: Keith Homan/Shutterstock; 29 construction set: tam_odin/Shutterstock; 29 chess game: goh seok thuan/Shutterstock; 29 bottom silver toys: Iain McGillivray/Shutterstock; 29 bottom cube toys: Anyaivanova/Dreamstime; 31 photo in green frame: Sundus Butt; 30-31 all other photos: Lorne Chapman for Scholastic Canada Ltd; 32 electrostatic charge: Ontario Science Centre; 32 magnetic field: Cordelia Molloy/Science Source; 32 magnetic: revers/Shutterstock; 32 magnetize: Derek Griffiths for Scholastic Canada Ltd; 32 neutral charge: GIPhotoStock/Science Source; 32 magnet, north pole, south pole: Dannyphoto80/Dreamstime. Illustrations ©: 2-3: Dave Whamond; 6-7: Bojan Redži´c; 10-11: Kevin Frank; 22-23: Ben Hodson; back cover: Chris Jones ISBN 978-1-4430-4765-4 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, in any form or by any means, without the prior written consent of the publisher or a license from The Canadian Copyright Licensing Agency (Access Copyright). For an Access Copyright license, call toll free to 1-800-893-5777. Printed in Canada

Static-Charged Jokes Where do you grow What did one magnet say a magnet? to the other magnet? How did the scientist pay for her magnets? How did the balloon Why did the feel about losing lightning go to the doctor? its electrical charge? 9 ISBN 978-1-4430-4765-4 fLroomokthinessiedejofkoer sa!nswers. You’ll get a chargeinvisible forces mag bcode 781443 047654 Invisible Forces