Science_Year_3_

Leisure Science My Coin Box Steps Create coin boxes of various sizes with used materials. Use your knowledge in measurement that you have learnt to create the coin boxes. 12 3 Let’s Remember 1. The measuring units for area and volume are: Area Volume Unit Symbol Unit Symbol mℓ square centimetre cm2 millilitre ℓ cm3 square metre m2 litre m3 square kilometre km2 cubic centimetre cubic metre 2. There are two types of surface areas: (i) regular surface (ii) irregular surface 3. Area is measured using: (i) 1 cm x 1 cm paper squares (ii) graph paper 4. The volume of a hollow box is measured using 1 cm x 1 cm x 1 cm-sized cubes. 5. The volume of an irregular shaped solid is measured by the water displacement method. 6. The volume of liquid is read with the position of the eyes at the level of the meniscus. 7. Measurement is important in daily life to calculate areas and volumes accurately to avoid wastage. 93

Let’s Answer Answer all the questions in the Science exercise book. 1. Write the following area and 3. Estimate the surface area of the volume in words. object below. (i) 2 cm2 (ii) 10 cm3 2. Surface area can be measured using ______ paper and 1 cm x 1 cm paper ______. 4. Calculate the volume of the object below. (i) Initial Final (ii) volume volume Before After 5. Calculate the volume of the hollow HOTS boxes. (i) (ii) How do we measure the volume of a nail using the apparatus 3 cm below? 2 cm 2 cm 3 cm 3 cm 3 cm 6. Lim’s father wants to install tiles full glass of water basin on the floor of his house. What will happen if Lim’s father does not syringe nail thread measure the floor of his house? 94

7 DENSITY Father, my toy duck floats! Why doesn’t the toy duck sink? 95

Float and Sink There are objects or materials around us that float on the surface of water and those that sink. What are the objects that float and what are the objects that sink? The stone sinks! Let’s throw a stone into the water. This branch floats. 7.1.1 96

Let’s Test Testing Objects that Float and Objects that Sink Apparatus and Materials • small aquarium • coin • ping-pong ball • marble • soap • cork • sponge Steps Table A 1. Fill the aquarium with water. Object Sink Float 2. Put all objects to be tested in Coin the aquarium. 3. Observe whether each object Ping-pong ball floats or sinks. Marble 4. Record your observations as in Table A. Soap Questions Cork Sponge Based on the activity above: (i) Which objects float? (ii) Which objects sink? Why do objects float or sink? Activity Book 97 Page: 63

Density The floating or sinking of an object is related to the density of the object against the density of water. Observe the situation below. The sponge has a lot The soap has of air space. no air space. air space Hey! The The soap sinks. sponge floats. The density of objects is different from one to another. There are objects that are more dense than water and objects that are less dense than water. Objects that are less dense than water will float. Objects that are more dense than water will sink. 7.1.2 Activity Book Pages: 98 64-65

Why do logs float on the surface of water but rubber bands sink in water? Water Becomes More Dense Oh! It looks like the The grape will float when the grape is more dense water becomes more dense. than water. How can that Can this grape float happen? on the surface of the water? 7.1.2 Activity Book 99 7.1.3 Pages: 64-66, 68

When salt is dissolved in water, the water will become more dense. Therefore, the grape that sank before, can now float. Water becomes more dense when salt is added to it. What will happen if sugar is added to water? Let us carry out an experiment. Let’s Test Floating a Fish Model on Water Apparatus and Materials • beaker • cutter Caution • 200 mℓ of water • sugar • spatula • carrot Place the fish Steps model and one spoonful 1. Caution 2. of sugar in the water. Carve out the shape of a fish Add more from the carrot. sugar and stir until the fish 3. 4. model floats. Stir to dissolve all the sugar. 5. Discuss your observation. 100 7.1.3 Activity Book 7.1.4 Page: 68

Questions 1. How many spoonfuls of sugar are needed to make the fish model float? 2. Why does the fish model float when sugar is added to the water? Fun Activity Density of Liquids Apparatus and Materials • plastic bottle • beaker • funnel • 100 mℓ of coloured water • 100 mℓ of cooking oil • 100 mℓ of glycerine Steps 1. Pour the coloured water into the bottle using the funnel. Then, pour in the cooking oil. 2. Screw on the bottle cap tightly and shake it. Leave it for a while. Observe the changes that take place. 3. Pour the glycerine slowly into the bottle and observe the changes. 4. Record your observations. Then, discuss. Question Compare the density of coloured water, cooking oil, and glycerine. Which is the most dense? TEACHER’S NOTES 101 • Glycerine is available at a pharmacy or baking supplies store.

Applications of Density in Life What are the applications of density in life? Ships and anchors are made of iron. A ship floats on the surface of the water but an anchor sinks. Why? Safety Farming Life jacket Fish farming enclosures How is density applied in the above situations? 102 7.1.1 Activity Book 7.1.4 Pages: 63, 67

Fun Activity Submarine Project Apparatus and Materials • plastic bottle • weight • basin • clay • adhesive tape • 40 cm tube Steps 1. Make a hole in the 2. Make several holes 3. Attach the weight bottle cap and insert along one side of to the bottom of the the tube into the the bottle. bottle using adhesive opening. tape. 4. Screw on the bottle cap with the inserted tube. Seal the opening in the bottle cap with clay. 5. Fill the basin with water and submerge the submarine model in the water. 6. Blow air into the submarine model through the tube. 7. Observe the situation. Then, discuss. Question State two importance of density in life. Leisure Science Dancing Egg Shells Steps 1. Put vinegar and crushed egg shells into a bottle and immediately screw on the bottle cap tightly. 2. Shake the bottle and observe the changes that take place. 103

Let’s Remember Sink Objects Object is underwater 1. Float Object is on the surface of the water Object is Object is less dense than water more dense than water 2. The density of each object and liquid is different. 3. Water can be made more dense by adding salt or sugar to it. 4. Density applications in daily life are life jackets, iron anchors, and buoy at fish farming enclosures. Let’s Answer Answer all the questions in the Science exercise book. 1. Which of the following will float on water? paper clip apple quill grape 2. An object that is ______ dense than water will sink. 3. Oil will ______ on the surface of the water as oil is ______ dense than the water. 4. How does a life jacket save a life? HOTS How can we sink an orange in water? 104

8 ACID AND ALKALI Why do their facial expressions change after tasting lemon and coffee without sugar? 105

Acidic, Alkaline, and Neutral There are substances around us that have acidic, alkaline, and neutral properties. The properties of these substances can be tested using litmus paper. Litmus paper is an indicator that changes colour when tested. Litmus paper has two colours, which are blue and red. red litmus blue litmus paper paper Change in Colour of Litmus Paper with an Acidic Substance When an acidic substance is tested, only blue litmus paper changes colour to red. acidic substance Observation: Blue  Red No change HOTS Can litmus paper be dipped directly into the substance to be tested? Explain. 8.1.1 106

Change in Colour of Litmus Paper with an Alkaline Substance alkaline substance When an alkaline substance is tested, only red litmus paper changes colour to blue. Observation: No change Red  Blue Change in Colour of Litmus Paper with a Neutral Substance neutral substance When a neutral substance is tested, there is no change in colour for both types of litmus paper. Observation: No change No change Which indicator is used to test substances for acidic, Activity Book alkaline or neutral properties? Pages: 69-71 107

Let’s Test Testing a Substance Using Litmus Paper Apparatus and Materials • dropper • petri dishes • tile • beaker • red and blue • filter paper litmus papers • funnel • orange juice • sugar solution • vinegar • drinking water • slaked lime • sodium bicarbonate solution Steps solution 1. Pour the vinegar into a labelled 2. Test the vinegar with the red and petri dish. blue litmus papers. 3. Observe the change in colour of the litmus papers and record the results as in Table A. Table A Substance Change in colour of Change in colour of blue litmus paper red litmus paper Vinegar Blue  Red  Drinking water Blue  Red  4. Repeat steps 1 to 3 using other substances. Question What is the property of a tested substance based on the change in colour of litmus paper? 108

Acidic, Alkaline, and Neutral Substances Besides litmus paper, we can also test the properties of substances using our senses of taste and touch. This lemon tastes This cabbage This water is sour. tastes bitter. tasteless. Most acidic substances taste sour and have a burning sensation when touched, while most alkaline substances taste bitter and feel slippery when touched. Neutral substances have different tastes such as tasteless, sweet, and salty. Neutral substances may feel slippery or coarse when touched. What about coffee? It tastes bitter but when it’s tested with blue litmus paper, the colour changes to red. Bitter substances are not always alkaline and sour substances are not always acidic. Can the senses of taste and touch be used as indicators for acidic, alkaline, and neutral properties of substances? Why? 8.1.2 Activity Book Pages: 109 72-74

Let’s Test Testing Acidic, Alkaline, and Neutral Properties Apparatus and Materials • red and blue • fresh milk • salt solution • ketchup litmus papers • filter papers • ice cream sticks • dropper • petri dishes • tile • grapes • egg white • toothpaste Steps 1. Put the substances to be tested into labelled petri dishes. 2. Taste the first 3. Touch the first 4. Test the first substance substance with your substance with your with red and blue tongue. finger. litmus papers. 5. Repeat steps 2 to 4 with the other substances. Property of 6. Record the results as in Table A. substance Table A Substance Taste Touch Change in litmus paper Fresh milk Blue Red Salt solution Blue Red Question What are the properties of acidic, alkaline, and neutral substances when tasted and touched? 110 8.1.2 TEACHER’S NOTES 8.1.4 • Teachers may use other suitable substances for the test. Examples are cooking oil, honey, tamarind, rice water, and others.

Acidic, Alkaline, and Neutral Substances Around Us There are acidic, alkaline or neutral substances around us other than food. These substances are used in the fields of agriculture, medicine, health, and industry. Fun Activity Me-Share-Agree Apparatus and Materials Steps • three situation cards 1. Form groups of four. Decide on a leader. 2. Each group prepares a Placemat Consensus. 3. The group leader chooses one situation card to be discussed with the other group members. 4. Each group member writes his/her ideas in the “me” space on the uses of acidic, alkaline, and neutral substances based on the situation card chosen. 5. After five minutes, discuss the ideas written down with other members in the group. 6. The results of the discussion are written in the “share” space. 7. Present the ideas for discussion in front of the class. Question • example of Placemat What are other uses of acidic, alkaline, Consensus and neutral substances in our daily life? Discuss. 8.1.4 TEACHER’S NOTES Activity Book Page: • The activity above is carried out using the Placement Consensus 111 of the 21st Century Learning Skills. 76

Litmus Paper Substitutes Besides litmus paper, we can also test acidic or alkaline properties of substances using other substances as indicators. Let’s Test Exploring Substitutes for Litmus Paper Apparatus and Materials • dropper • turmeric • purple • hibiscus • petri dishes extract cabbage extract • lime extract • sodium bicarbonate Add 5 mℓ of lime extract to one petri dish Steps and 5 mℓ of sodium bicarbonate solution to another. 1. 2. Put a drop of turmeric extract in both petri dishes and observe the colour changes. Record your observation. 3. Repeat steps 1 and 2 using purple cabbage and hibiscus extracts. 4. Test all acidic and alkaline substances other than the lime extract and sodium bicarbonate solution. 5. Record the observations of any colour change. Discuss. Questions 1. Which tested extract is only affected by alkaline? 2. Other than lime extract and sodium bicarbonate solution, what other test substances can be used? 3. Are turmeric, purple cabbage, and hibiscus extracts suitable to be used as indicators for the properties of acidic and alkaline substances? 8.1.3 TEACHER’S NOTES Activity Book Page: 112 • pH paper may be used as a substitute for litmus paper. • The methods to prepare extracts of turmeric, purple cabbage, 75 and hibiscus can be seen by scanning the QR Code.

Leisure Science An Acidic, Alkaline, and Neutral Tree Steps 1. Create an acidic, alkaline, and neutral tree craft by decorating its branches and twigs using pictures of acidic, alkaline, and neutral substances. 2. Add an empty space at the bottom of the tree craft for your stationery. Let’s Remember 1. Acidic, alkaline or neutral properties can be tested using litmus paper. 2. Litmus paper has two colours which are blue and red. 3. The change in colour of litmus paper during testing is as follows: Litmus paper Acidic Alkaline Neutral colour substances substances substances Blue Changes to red No change No change Red No change Changes to blue No change 4. Examples of acidic, alkaline, and neutral substances: Acidic substances Alkaline substances Neutral substances Lime Soap Salt solution Tamarind Slaked lime Sugar solution 5. The acidic, alkaline, and neutral properties of a substance can also be tested using the senses of taste and touch, although these are not scientific indicators. 6. Acidic substances usually taste sour, while alkaline substances taste bitter and are slippery when touched. Whereas, neutral substances have many types of taste, such as tasteless, salty, and sweet. 7. Other substances that can be used to test acidic, alkaline or neutral substances are: • turmeric extract • hibiscus extract • purple cabbage extract 8. Acidic and alkaline substances are widely used in agriculture, medicine, and the manufacture of household products. 113

Let’s Answer Answer all the questions in the Science exercise book. 1. What is the indicator used to test acidic, alkaline or neutral substances? 2. (i) What are the properties of X, Y, and Z based on the change in the colour of litmus paper? Properties of X Properties of Y Properties of Z (ii) What are examples of X, Y, and Z? 3. Besides litmus paper, acidic and alkaline substances may also be tested using extracts of _____, _____, and _____. 4. Amar tested bitter gourd extract and recorded the results as in Table A. Taste Table A Touch Bitter Change in litmus paper Slippery (i) Blue  red (ii) Red  no change Based on the results above, can the senses of taste and touch be used as scientific indicators for the properties of bitter gourd? Why? HOTS Why does toothpaste have alkaline properties? 114

9 THE SOLAR SYSTEM Langgi and his family are watching a presentation at the National Planetarium space theatre. Wow! It’s so beautiful. What’s that, father? What is shown on the theatre screen? 115

Members of the Solar System The Solar System is made up of the Sun, planets, natural satellites, asteroids, meteoroids, and comets. Let us get to know our Solar System. Uranus comet Sun Jupiter Mercury Earth Natural objects revolving around a planet are known as natural satellites. The Moon is a natural satellite of the Earth. Moon The Sun, which is the centre of the Solar System, is surrounded by other members of the Solar System. Where is the position of the Sun in the Solar System? TEACHER’S NOTES 9.1.1 • The illustration of the Solar System is not to scale. 116

asteroid Venus Saturn Mars Neptune Collisions between asteroids produce smaller pieces of rock in outer space known as meteoroids. meteoroid State the sequence of the planets in the Solar System starting from the Sun. TEACHER’S NOTES Activity Book 117 Pages: • Pluto was once classified as the 9th planet of the Solar System. It was classified as a dwarf planet in 2006. 77-79, 84 • Facts about the planets in the Solar System are available at https://solarsystem.nasa.gov/planets/

Fun Activity Solar System Balloons Apparatus and Materials • marker pen • manila cardboard • adhesive tape • balloons Steps 1. Blow up the balloons 2. Mark ‘X’ at the centre of the manila according to the estimated cardboard. Then, draw eight circles sizes of the Sun and the eight of different sizes. planets. 3. Attach the balloons onto the 4. Label every planet. Draw the circular lines according to the asteroids, meteoroids, and comets sequence of planets in the on the manila cardboard. Solar System. 5. Present your Solar System Balloons to the class. Questions 1. List the members of the Solar System. 2. Where is the asteroid located in the Solar System? 118 9.1.1 77-99, 9.1.5 84

Fun Activity Interactive Card Apparatus and Materials • scissors Caution • coloured paper • pictures of planets • glue Steps Caution 1. Fold the paper in half. Then, cut 2. Push the fold between the two the centre part of the fold as in cuts upwards. the diagram. Caution 3. Cut the picture of the planet and 4. Write information about the paste it on the upward fold of planet on the cardboard. the card. Decorate the card creatively. 5. Repeat steps 1 to 4 for other members of the Solar System. Question Besides Saturn, which planet has a ring? TEACHER’S NOTES 119 • More information about the members of the Solar System is available at https://solarsystem.nasa.gov/

Temperature of the Planets Is the temperature of every planet the same? Let us follow the conversation between Lim and his friends. Lim, why are It’s hot We don’t feel hot you sweating? here! over here. It’s hot here because I’m Oh! Can we relate this situation standing near the fire. to the temperature of the planets that we’re learning about? 9.1.2 84 120

The Sun is the source This planet is the closest This planet is the of heat for the Solar to the Sun. Therefore, farthest from the Sun, System. Its temperature its temperature must be so its temperature is very high. higher than any other must be the lowest. planets. What can you state about the temperature of the planets? The temperature of the However, Venus nearest planet to the has the highest Sun is higher than the temperature in temperature of the farthest the Solar System planet from the Sun. because of its thick atmosphere that traps heat. HOTS If the Earth were located in Uranus’s position, would it be suitable for life? Why? TEACHER’S NOTES Activity Book 121 Pages: • An atmosphere is a layer of gas that surrounds a planet. • An interactive activity on planet temperature can be found at 80-81 https://bukuteks.dbp.gov.my/media.php?id=1336

Orbit of Planets The car is moving very fast on the track! Just like the car track, each planet revolves around the Sun in its own path called an orbit. orbit The orbit is an elliptical How does a planet imaginary path that goes revolve around the Sun around the Sun in space. in the Solar System? 9.1.3 TEACHER’S NOTES Activity Book Pages: 122 • An ellipse is a regular oval shape (almost like the shape of an egg). • An interactive activity on the orbits of planets can be found at 82-83 https://bukuteks.dbp.gov.my/media.php?id=1337

Fun Activity An Orrery of the Solar System Apparatus and • ruler • cardboard • paper cup Materials • adhesive tape • coloured pencils • paper fastener Steps • scissors Caution • cutter Caution • hole punch Caution Caution 1. Draw and cut pictures of the 2. Cut the cardboard into eight strips Sun and the planets. of different lengths. 3. Paste the picture of each planet 4. Make a hole at the other end of at one end of every strip in a each strip and at the bottom of sequence. the paper cup. 5. Tie all the strips together at the 6. Paste the picture of the Sun at the bottom of the paper cup using centre of the model and label it. the paper fastener. 7. Discuss the Solar System using the orrery model. Questions 1. What does the length of the strips in the orrery model represent? 2. State the planets in sequence starting from the nearest to the Sun. 9.1.3 TEACHER’S NOTES 123 9.1.5 • An orrery is a special type of clockwork model invented by George Graham to compare the position and movement of the planets in the Solar System.

Revolution Time of the Planets The time taken for each planet to revolve around the Sun is different. Observe the situation below. What is the difference between the Earth’s orbit and Mars’s orbit? Mars is farther from So, the pathway of the Sun compared to Mars in its orbit is the Earth. longer. Mars’s orbit Earth’s orbit Mars Earth Sun In conclusion, the time taken for Mars to revolve around the Sun is longer compared to the Earth. As the distance between a planet and the Sun increases, the time taken for it to make one complete revolution around the Sun also increases. HOTS The Earth takes one year to make one complete revolution around the Sun. Compare the time taken for other planets to revolve around the Sun in the unit of Earth Year. 9.1.4 TEACHER’S NOTES Activity Book Page: 124 • Earth Year is a unit for the time taken by the Earth to make one complete revolution around the Sun. 83

Let’s Test Relating the Distance of Planets from the Sun and the Time Taken to Make One Revolution Apparatus and Materials • stopwatch • wooden pole • long rope • adhesive tape Steps rope timekeeper 1. Stick a wooden pole in wooden pole the field. starting 2. Mark eight different lengths on line the rope. circle path 3. Tie the rope to the pole and Length of Table A hold the other end of the rope. rope (m) Time taken to make one complete circle (seconds) 4. Mark the starting position 1 using adhesive tape and move 2 around the pole to make one 3 complete circle. 5. Record the time taken as in 4 Table A. 5 6. Repeat steps 3 to 5 using 6 7 different lengths of the rope. 8 Question What is the relationship between the distance of your position from the centre of the circle and the time you revolve around the centre of the circle? Leisure Science My Planet Lantern Steps 1. Cut and write information about planets on coloured paper strips. 2. Attach the coloured paper strips together using a paper fastener. 3. Form the coloured paper strips into a sphere. 4. Decorate your Planet Lantern. 9.1.4 TEACHER’S NOTES Activity Book 9.1.5 Pages: • The time of a revolution is the time taken to make one complete circle. 83-84 125

Let’s Remember 1. The Solar System natural satellite asteroid meteoroid comet Saturn Neptune Venus Mars Mercury Earth Jupiter Uranus The temperature of planets that are nearer to the Sun is higher than the temperature of planets farther from the Sun. 2. All planets revolve around the Sun in their orbits. 3. As the distance between a planet and the Sun increases, the time taken for it to make one complete revolution around the Sun also increases. Let’s Answer Answer all the questions in the Science exercise book. 1. What is the position of the Earth in the sequence of planets around the Sun? 2. What are the objects located between Mars and Jupiter? 3. _____ is the coldest planet in the Solar System. 4. Uranus revolves around the _____ in its orbit. 5. Arrange the planets in sequence of increasing planet temperature. Earth Jupiter Neptune Saturn Venus 6. Which planet requires the least time to make one complete revolution around the Sun? Why? Venus Mars Saturn Neptune Mercury Earth Jupiter Uranus 126

10 MACHINE Lim and his father are chatting on the balcony of their house. Father, what is that Oh! That is a moving object? crane lifting building materials. How does the The crane lifts the crane lift building building materials with materials? the help of a pulley. pulley Where can you see pulleys other than in the situation above? 127

Pulleys How does this cable car move? It moves using a pulley. Pulley is an example of a simple machine which enables load to be lifted easily using lesser force. Parts of a Fixed Pulley groove wheel axle rope load A fixed pulley has a wheel with What is a pulley a groove that enables a rope to and its use? pass through it. Activity Book 10.1.1 Page: 85 128

The Functions of a Fixed Pulley This is a crane model. It has a base, pole, arm, pulley, and rope. How does this model work? The fixed pulley on the crane model works when all the components are connected. What are the components? base pole arm load 1 yellow pulley rope 1 black pulley (acts as a motor) (acts as a fixed pulley) TEACHER’S NOTES 10.1.2 • Any suitable model other than the model shown can be used. 129

How does the fixed pulley work on the crane model? 12 Before a load is While a load is lifted being lifted 3 When the rope is pulled, the load will be lifted upwards by the fixed pulley. After a load is Activity Book lifted Page: What about the pulley model you 86 use in school? Explain how the pulley model works. 130

Uses of Pulleys What are the examples of pulleys used in our life? What will happen if the flagpole does not have a pulley? What is the difference between lifting a bucket of water from the well using a pulley and without using a pulley? Which is easier? Why? 10.1.3 131

What will happen if the fishing nets are not pulled using a pulley? What will happen if the heavy objects are lifted without using a pulley? What are other applications Activity Book of pulleys in our life? Pages: 132 87-89

Invent a Functioning Pulley Model Pulleys make lifting load easier. How would you build a functioning pulley model to solve the problem of lifting loads? 1 Identifying the Problem 2 Generating an Idea The residents of the apartment I suggest we make a pulley. are carrying water from a lorry because the water supply has Let’s build a been cut off. functioning pulley model. We can use recycled materials. How can we make carrying water to the upper floor easier? 3 Sketching Out Ideas 4 Preparing Apparatus and Materials Caution 10.1.4 TEACHER’S NOTES Activity Book 133 10.1.5 Page: • A pulley model can be built according to pupils’ creativity and is not limited to the example above. 90

5 Building a Pulley Model A Caution B C Caution Measure, mark, and Make a hole in the Attach the parts of the cut the box and the centre of the box. box to the bottle that bottle. E has been cut. D F Insert a straw into the Pierce the stick Hang and test the hole to make an axle. through the end of completed pulley. the straw. Build a workable This pulley model has pulley model in been used to produce a a creative way. fixed pulley that can lift water to the upper floor. 134

Types of Pulleys Besides the fixed pulley, there are several types of pulleys such as compound pulleys and movable pulleys. Compound pulley Movable pulley Where can we find the use of these pulleys? Find information on the types of pulleys from various media. At the Port A pulley on a crane makes it easier to unload a shipping container from the ship to the lorry. Is the pulley at the port the same as the pulley used on a flagpole? Find the information on the types of pulleys and discuss. HOTS Activity Book 135 Page: How does the pulley move a heavy container from the ship to the lorry easily? 91 10.1.3 10.1.5

At the Construction Site A pulley on a crane makes lifting the building materials easier. HOTS What will happen to the process of constructing a building if pulleys are not used? Leisure Science My Crane Model Steps Build a crane model using recycled materials such as boxes and sticks. 1 Caution 2 3 Caution 45 6 7 136 Activity Book Page: 92

Let’s Remember 1. A pulley is a type of simple machine used to lift loads easily. 2. A fixed pulley contains several components: (i) groove (iii) rope (ii) wheel (iv) axle 3. A pulley functions when the rope is pulled through the groove to lift the load. 4. Besides fixed pulleys, there are other types of pulleys used to make work easier, such as pulleys used at construction sites and at ports. 5. Examples of the application of fixed pulleys in our life are: (i) raising the flag (iii) pulling up fishing nets (ii) lifting water from a well (iv) lifting building materials Let’s Answer Answer all the questions in the Science exercise book. 1. What is a pulley? 3. Based on Figure 1, explain how 2. Name the parts of a pulley. the load is lifted. (iii) (i) (iv) load Figure 1 4. List two uses of pulleys in our daily activities. 5. State the functions of pulleys at (ii) the following places: (i) construction site (ii) port 137

ANSWERS 4. (i) lions and wolves (ii) orangutans and chimpanzees (iii) giraffes and goats 5. Incisors to cut food and molars to grind food into small pieces. Unit 1: Scientific Skills HOTS suggested answer (page 70) Animals would adapt to their environment by looking for sources of food that HOTS suggested answer (page 7) can be eaten for their survival. No, because the measuring tool used is different. Let’s Answer (page 22) Unit 5: Plants 1. Sight, smell, taste, touch 2. Animals with four legs, Animals with fur Let’s Answer (page 78) 3. length 4. Green or blue 1. (a) (i) stem cutting (ii) underground stems (iii) spores 5. Not enough electrical energy, the dry cells are not fastened, bulb is damaged. 6. graph (b) (i) tapioca (ii) ginger (iii) ferns 7. (i) False (ii) True (iii) False (iv) True 8. After completing a science investigation, we should clean, dry, and store away 2. The reproduction of plants is important for life so that food sources, habitat, the science apparatus properly. HOTS suggested answer (page 22) oxygen, and supply of wood will be conserved and will always be available. Advise my friend and tell him about the steps that should be taken when disposing of soil specimen, as the sink will be clogged if the soil specimen 3. Water spinach and sweet potato is thrown into it. 4. Orchids and bananas Unit 2: Science Room Rules Unit 6: Measurement Let’s Answer (page 28) Let’s Answer (page 94) 1. Line up before entering the Science Room, do not eat in the Science Room, place 1. (i) two square centimetres (ii) ten cubic centimetres all bags outside the Science Room, turn off the switches before leaving the 2. graph, squares Science Room, carry out activities in the teacher’s presence. 3. 7 cm2 2. Not enough air and light may cause the activity to be carried out in an uncomfortable condition. 4. (i) 10 mℓ (ii) 30 mℓ 3. No, because it will spoil the table top in the Science Room. 5. (i) 12 cm3 (ii) 27 cm3 4. (i) the hand lens and specimen will be damaged. 6. Wastage or not enough tiles (ii) the hand lens and specimen will not be damaged. HOTS suggested answer (page 94) 5. Report to the teacher immediately. HOTS suggested answer (page 28) Place a full glass of Tie a nail with Immerse the nail Measure the These rules can be practised in other special rooms such as the resource centre, water in a basin. thread. in the water in displaced water music room, computer room, RBT workshop, prayer room and others. the glass. using a syringe. Unit 3: Humans Unit 7: Density HOTS suggested answer (page 36) Let’s Answer (page 104) Teeth would not last long. The number of teeth would not be enough for an adult. 1. apple and quill 2. more Teeth would be small and not strong. 3. float, less Let’s Answer (pages 57-58) 4. A life jacket will float on the surface of the water because it is less dense than water, so it can prevent someone from drowning. 1. Incisors are for cutting food, canines are for tearing food, and molars are HOTS suggested answer (page 104) Peel the skin of the orange. for grinding food into small pieces. Unit 8: Acid and Alkali 2. (i) enamel (ii) dentine (iii) gum (iv) nerves (v) blood vessels HOTS suggested answer (page 106) No, because the litmus paper needs to be moist before testing a dry substance. 3. Milk Teeth Set Permanent Teeth Set A liquid substance needs to be dropped onto the litmus paper. Let’s Answer (page 114) There are 20 teeth: There are 32 teeth: 1. litmus paper 2. (i) Property of X – Neutral ; Property of Y – Alkaline ; Property of Z – Acidic • 8 incisors • 8 incisors (ii) Substance X - Drinking water ; Substance Y – Soap ; Substance Z - Lemon juice • 4 canines • 4 canines 3. turmeric, purple cabbage, hibiscus 4. Taste and touch cannot be a scientific indicator because most bitter substances • 8 molars • 20 molars that are slippery when touched are alkaline. However, bitter gourd is acidic as it changes litmus paper from blue to red. Thin layers of enamel and dentine. Hard layers of enamel and dentine. HOTS suggested answer (page 114) Toothpaste can neutralise acid in the mouth. Teeth are smaller and not strong. Teeth are bigger and stronger. Teeth are not permanent. Teeth are permanent. They last for a short time. They last for a longer time. Teeth start to grow at 6 months old Teeth start to grow at 6 years old and and are complete at 3 years old. are complete at 21 years old. Both sets have the same types of teeth, which are incisors, canines, and Unit 9: The Solar System molars. 4. Rinse the mouth, brush the teeth or use floss. HOTS suggested answer (page 121) 5. Protein - Fish, Carbohydrate - Bread 6. To keep the body warm The Earth would no longer be suitable for life because it would be too cold. 7. Papaya Tomatoes 8. (i) Yes (ii) This is because nasi lemak contains all the food classes from HOTS suggested answer (page 124) every level of the Malaysian Food Pyramid. 9. A balanced diet helps to keep our bodies healthy. Mercury and Venus take less than one Earth Year to revolve around the Sun, 10. Digestion is a process to break down food into small parts so that the nutrients from food are easily absorbed by the body. whereas Mars, Jupiter, Saturn, Uranus, and Neptune take longer than one 11. P - Mouth, Q - Oesophagus, R - Stomach, S - Intestine, T - Anus 12. It will be removed from the body through the anus as faeces. Earth Year. 13. (ii) eating in the park. HOTS suggested answer (page 58) Let’s Answer (page 126) Because the body’s requirement for each food class is different depending on age, sex, occupation, and health condition of a person. 1. Third 4. Sun Unit 4: Animals 2. Asteroid 5. Neptune, Saturn, Jupiter, Earth, and Venus HOTS suggested answer (page 64) 3. Neptune 6. Mercury, because its orbit is the smallest. Not all omnivores have the same set of teeth because certain omnivores do not have teeth, such as chickens and doves. Unit 10: Machine HOTS suggested answer (page 135) The pulley on the crane at the port can lift up a heavy shipping container using lesser force. Therefore, the heavy shipping container can be moved from the ship to the lorry easily. HOTS suggested answer (page 136) The process of constructing a building without the use of pulleys will take a longer time and need more workers. Let’s Answer (page 137) 1. A pulley is a simple machine that makes the lifting of loads easier using a Let’s Answer (page 70) lesser force. 1. (i) Omnivore because bat eats fruits and insects (ii) Carnivore because frog eats other animals only 2. (i) groove (ii) rope (iii) wheel (iv) axle (iii) Herbivore because cow eats plants only 2. (i) goats and rabbits (ii) eagles and tigers (iii) chickens and monkeys 3. The load can be lifted when the connected rope is pulled through the groove. 3. (i) Other animals (ii) plants (iii) Other animals and plants When the rope is pulled, the wheel turns and the load is lifted upwards. 4. Raise a flag, lift a bucket of water from a well, pull the fishing nets 5. (i) lifting construction materials (ii) easing the unloading of a shipping container 138

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ISBN 978-983-49-2215-3 9 789834 922153 BT073005