PAGE 1: How we will learn OVERVIEW ======== Matter is anything that occupies space and has mass. In this sub-strand you will sort substances from the environment into solids, liquids and gases, and describe the shape, volume and mass of each state. You will also see why each state of matter is useful in daily life. ## Strand 2.0: Matter Sub-strand 2.1: Properties of matter Suggested lessons: 14 ## What this sub-strand covers • Meaning of matter • States of matter (solid, liquid and gas) • Properties of matter (shape, volume and mass) • Importance of the different states of matter ## Source • KICD Grade 4 Science and Technology Curriculum Design (Revised 2024) — Strand 2.0 Matter, Sub-strand 2.1 Properties of matter ## Learning outcomes By the end of the sub-strand, the learner should be able to: a) categorise substances in the environment into the three states of matter b) describe the properties of the three states of matter c) appreciate the importance of the different states of matter in day-to-day life ## Key inquiry questions 1. What are the properties of matter? ## Learning experiences • brainstorm on the meaning of matter and identify its different states • collect and group different substances from the environment into the three states of matter collaboratively • carry out activities to demonstrate the properties of the three states of matter with peers • discuss the importance of the different states of matter in day-to- day life • use digital or print media to search for more information on the characteristics of the three states of matter ## Core competencies • Communication and collaboration: The learner shares different roles as they works with peers to collect and group different substances from the environment into the three states of matter and carry out activities that show properties of matter. • Digital literacy: The learner develops digital manipulative skills as they interact with digital technology to observe the properties of the three states of matter. ## Values • Unity: The learner shares available resources amicably as they carry out activities to demonstrate the properties of the three states of matter with peers. ## Pertinent and contemporary issues • Heath issues -preventive health: The learner practices preventive health measures such as avoiding blowing air into the same balloon with others as they carry out activities to demonstrate the properties of the three states of matter with peers. ## Links to other learning areas • Mathematics: The learner uses the knowledge of properties of matter to measure the volume and mass of different substances. PAGE 2: Lesson 1: The meaning of matter — Notes 1 LESSON 1: THE MEANING OF MATTER =============================== ## What you will learn • Explain the meaning of matter. • Give examples of things that are matter and things that are not matter. Curriculum outcomes: a) categorise substances in the environment into the three states of matter ## Introduction Hold a stone in one hand and an empty open hand beside it. The stone stops your fingers from closing, and it feels heavy. Those two clues — it takes up space and it has mass — are how we recognise matter. ## Notes Matter is anything that occupies space and has mass. Occupies space means it takes up room, so two things cannot be in exactly the same place at the same time. A book on your desk occupies the space where it lies. Water poured into a bottle occupies part of the bottle. Even the air in an “empty” cup occupies space. If you push an inverted glass straight down into a basin of water, water does not fill the glass at once, because air is already inside it. Mass is the amount of matter in an object. A large stone has more mass than a small pebble. A jerrycan full of water has more mass than the same jerrycan when it is empty. When you lift an object, you feel its mass as weight. ### Things that are matter Look around the classroom. The walls, the floor, the desks, the chalk and your clothes are all matter. Drinking water is matter. The milk in a packet is matter. The air you breathe is matter, even though you cannot see it. Your own body is matter too. PAGE 3: Lesson 1: The meaning of matter — Things that are not matter ### Things that are not matter Light, sound, heat and a shadow are not matter. They do not occupy space in the way a stone does, and they do not have mass. You cannot put light in a bottle or collect a handful of sound. Feelings and ideas, such as happiness or the number three, are not matter either. Scientists study matter because almost everything we use — food, water, tools, clothes and the air we breathe — is matter. In the lessons that follow you will group matter into three states and describe how each state behaves. [DIAGRAM] TYPE: svg ALT: A stone, water and air are all matter PAYLOAD: CAPTION: A stone, water and air are all matter [/DIAGRAM] ## Key words • matter — anything that occupies space and has mass • occupies space — takes up room so that something else cannot be in the same place • mass — the amount of matter in an object ## Worked examples ### Example 1 A learner says that the air in a football is not matter because it cannot be seen. Is the learner correct? Working: 1. Matter is anything that occupies space and has mass. 2. Air inside the ball occupies space, which is why the ball is firm. 3. Air also has mass, even though we cannot see it. Answer: No. Air is matter because it occupies space and has mass. PAGE 4: Lesson 1: The meaning of matter — Brainstorm: what is matter? ## Worked examples ### Example 2 Which of these are matter: a wooden ruler, sunlight, water in a cup, and the sound of a bell? Working: 1. A wooden ruler occupies space and has mass. 2. Water occupies space in the cup and has mass. 3. Sunlight and sound do not occupy space or have mass. Answer: The wooden ruler and the water are matter. Sunlight and sound are not matter. ## Activity: Brainstorm: what is matter? You will need: Manila paper or the chalkboard, A stone, a bottle of water and an empty open bottle 1. In a group, handle the stone, the bottle of water and the open bottle of air. 2. Discuss what the three things have in common. Agree on a meaning of matter. 3. Make two lists: Things that are matter and Things that are not matter. Include objects you can see in the classroom. 4. Share your lists with another group and correct any item that does not match the meaning. 5. Wash your hands after handling shared objects. ## Practice 1. What is matter? 2. Give two examples of matter found in a classroom. 3. Why is sunlight not matter? ## Answers to practice 1. Matter is anything that occupies space and has mass. 2. Any two, such as a desk, a book, chalk, water or air. 3. Sunlight does not occupy space and does not have mass. ## Summary • Matter is anything that occupies space and has mass. • Stones, water and air are matter. • Light, sound, heat and shadows are not matter. LESSON 2: THE THREE STATES OF MATTER ==================================== ## What you will learn • Name the three states of matter. • Give examples of solids, liquids and gases from the environment. Curriculum outcomes: a) categorise substances in the environment into the three states of matter ## Introduction Leave a piece of ice in a plate in the sun. It turns into a puddle of water. If that water is heated in a sufuria, steam rises from it. Ice, water and steam are the same substance in three different states. ## Notes Matter exists in three states: solid, liquid and gas. The state tells us how the substance behaves, not what colour it is or whether it is useful. ### Solids A solid has a shape of its own. A stone, a wooden spoon, a metal sufuria, a book, a piece of chalk and a block of ice are solids. You can hold most solids in your hand. Sugar and salt are also solids. Each grain is a tiny solid, even though the grains can be poured. PAGE 5: Lesson 2: The three states of matter — Same substance, different states ### Liquids A liquid flows and can be poured. Water, milk, cooking oil, juice, honey and paraffin are liquids. A liquid does not keep one shape. It spreads out until it meets the walls of the container it is in. The top of a still liquid is flat. ### Gases A gas spreads out to fill the space it is given. Air is a mixture of gases. The gas used for cooking is a gas. Steam rising from boiling water is water in the gas state, called water vapour. The air you blow into a balloon is a gas. You often cannot see a gas, but you can feel moving air and you can see a balloon grow bigger as gas goes into it. ### Same substance, different states Ice is solid water. Water you drink is liquid. Steam is water as a gas. Heating or cooling can change a substance from one state to another. The substance is still matter in every state. Do not touch steam or boiling water. Steam can burn the skin. Do not taste a substance just to find out its state. [DIAGRAM] TYPE: svg ALT: Solid, liquid and gas are the three states of matter PAYLOAD: CAPTION: Solid, liquid and gas are the three states of matter [/DIAGRAM] PAGE 6: Lesson 2: The three states of matter — Example 1 ## Key words • solid — a state of matter that has a shape of its own, such as a stone or a piece of ice • liquid — a state of matter that flows and takes the shape of its container, such as water • gas — a state of matter that spreads out to fill the space it is in, such as air • water vapour — water in the gas state, such as steam ## Worked examples ### Example 1 Sort these into solid, liquid and gas: cooking oil, a nail, air in a ball, honey, a brick. Working: 1. A nail and a brick keep their own shape, so they are solids. 2. Cooking oil and honey can be poured, so they are liquids. 3. Air spreads inside the ball, so it is a gas. Answer: Solids: nail and brick. Liquids: cooking oil and honey. Gas: air in the ball. ## Worked examples ### Example 2 A learner pours salt from a packet and says salt is a liquid because it flows. What is the correct state of salt? Working: 1. Each grain of salt keeps its own tiny shape. 2. The grains are small solids, not a liquid. 3. A liquid has no grains that keep their own shape. Answer: Salt is a solid. ## Activity: Identify the three states You will need: A stone or piece of wood, A cup of water, A balloon for each learner, Three labels: Solid, Liquid, Gas 1. Brainstorm with your group and name the three states of matter. 2. Place the stone, the cup of water and a balloon on the table. 3. Each learner blows up their own balloon. Do not share a balloon or blow into a balloon someone else has used. 4. Match each object to a label and say why. 5. Add three more examples from the classroom to each label. ## Practice 1. Name the three states of matter. 2. Give one example of a solid, one liquid and one gas. 3. Ice, water and steam are three states of which substance? 4. Why is salt a solid even though it can be poured? ## Answers to practice 1. Solid, liquid and gas. 2. Examples: stone (solid), water (liquid), air (gas). 3. Water. 4. Each grain of salt is a tiny solid that keeps its own shape. ## Summary • The three states of matter are solid, liquid and gas. • Solids keep their shape, liquids flow, and gases spread out. • Ice, water and steam are water in the three states. PAGE 7: Lesson 3: Grouping substances from the environment — How to decide the state LESSON 3: GROUPING SUBSTANCES FROM THE ENVIRONMENT ================================================== ## What you will learn • Collect substances from the environment. • Group them into solids, liquids and gases. Curriculum outcomes: a) categorise substances in the environment into the three states of matter ## Introduction On the way from home to school you pass stones, puddles, smoke from a kitchen and the wind on your face. Each of those is matter, and each one belongs in one of the three states. ## Notes To categorise substances means to put them into groups that share the same features. For states of matter, the three groups are solid, liquid and gas. ### How to decide the state Ask these questions about each substance: - Does it keep its own shape when you put it down? If yes, it is a solid. A maize cob, a bottle top, a leaf and a lump of clay are solids. - Does it flow and take the shape of the container, while you can still pour it from one container to another? If yes, it is a liquid. Tea, milk, rainwater and liquid soap are liquids. - Does it spread to fill the container, and is it difficult to hold in an open hand? If yes, it is a gas. Air, steam and the gas in a balloon are gases. PAGE 8: Lesson 3: Grouping substances from the environment — Example 1 ### Substances you can collect safely Around the school you can collect small solids such as pebbles, dry leaves, pieces of paper, bottle tops and sticks. Liquids should be in closed or open containers an adult has allowed, such as water or cooking oil. You cannot collect a gas in your bare hands. You can trap air in a balloon or in an inverted glass. ### Careful cases A wet cloth is a solid that has liquid in it. The cloth is the solid; the water in it is the liquid. Smoke from a fire is tiny solid bits carried in hot air. The air is a gas. Ice floating in a glass is a solid sitting in a liquid. Do not pick up broken glass, unknown powders or containers you cannot identify. Do not taste substances. Wash your hands after the collection. ## Key words • categorise — to put things into groups that share the same features • substance — a kind of matter, such as water, wood or air ## Worked examples ### Example 1 Group these substances: a dry leaf, milk, air in a tyre, a coin, porridge that can be poured, steam from ugali. Working: 1. The leaf and the coin keep their shape: solids. 2. Milk and pourable porridge flow: liquids. 3. Air in a tyre and steam spread out: gases. Answer: Solids: dry leaf, coin. Liquids: milk, porridge. Gases: air in the tyre, steam. ## Worked examples ### Example 2 A glass holds ice cubes and water. How many states of matter are in the glass? Working: 1. Ice cubes are solid water. 2. The water around them is liquid. 3. A little air sits above the water if the glass is not full, but the substances named are ice and water. Answer: Two states: solid (ice) and liquid (water). PAGE 9: Lesson 3: Grouping substances from the environment — Answers to practice ## Activity: Collect and group substances You will need: Three boxes or labelled manila charts: Solid, Liquid, Gas, Gloves or a stick for picking litter, A balloon, A small bottle of water 1. Walk with your teacher around the school compound and list substances you see. 2. Collect only safe solids, such as pebbles, dry leaves and clean bottle tops. Do not touch broken glass, sharp metal or animal waste. 3. Back in class, place each solid on the Solid chart. Put the bottle of water with the Liquid chart. Trap air in a balloon for the Gas chart. 4. Work together to add more examples to each group from memory. 5. Wash your hands with soap when you finish. ## Practice 1. What does it mean to categorise substances? 2. A learner finds a bottle top, cooking oil and air in a ball. State the group for each. 3. A wet shirt is hanging on a line. Which part is solid and which part is liquid? ## Answers to practice 1. To put them into groups that share the same features, such as solid, liquid and gas. 2. Bottle top: solid. Cooking oil: liquid. Air in a ball: gas. 3. The shirt is solid. The water in the shirt is liquid. ## Summary • Substances can be grouped as solids, liquids or gases. • Shape and the ability to flow help you decide the group. • Collect only safe substances and wash your hands afterwards. PAGE 10: Lesson 4: Shape of solids, liquids and gases — Solids have a definite shape LESSON 4: SHAPE OF SOLIDS, LIQUIDS AND GASES ============================================ ## What you will learn • Describe the shape of a solid, a liquid and a gas. • Show that a liquid takes the shape of its container. Curriculum outcomes: b) describe the properties of the three states of matter ## Introduction Move a stone from a box into a bowl. The stone looks the same. Pour water from a jug into that bowl. The water no longer looks like the jug. Shape is one property that separates the three states. ## Notes Shape is the outline or form of a substance. Shape is one property of matter. ### Solids have a definite shape A definite shape means the shape stays the same unless you break, cut or bend the solid. A brick stays brick-shaped on the table, in a box or in your hands. A metal spoon keeps its shape when you move it from a cup to a plate. You can change the shape of some solids by force: clay can be pressed, paper can be folded and a stick can be broken. Until you do that, the solid keeps its shape. ### Liquids have no definite shape A liquid takes the shape of the part of the container it fills. Water in a tall glass is tall. The same water poured into a wide plate is wide and shallow. The liquid itself has not changed; only the container has. The surface of a still liquid is level. Honey, milk and cooking oil behave in the same way, although thick liquids flow more slowly than water. ### Gases have no definite shape A gas also takes the shape of its container, then spreads to fill all of it. Air in a round balloon makes a round shape. Air in a long balloon makes a long shape. If the balloon bursts, the air does not stay in a ball. It mixes with the air in the room and has no shape of its own. When you compare shape, remember: solids keep their shape; liquids and gases take the shape of the container. A gas goes further and fills the whole container. PAGE 11: Lesson 4: Shape of solids, liquids and gases — Example 1 ## Key words • shape — the outline or form of a substance • definite shape — a shape that stays the same when the substance is moved • property — a feature that describes how matter behaves, such as shape, volume or mass ## Worked examples ### Example 1 Water is poured from a narrow bottle into a wide basin. What happens to the shape of the water? Working: 1. A liquid has no definite shape. 2. It takes the shape of the new container. 3. The water was narrow in the bottle and becomes wide in the basin. Answer: The water takes the wide shape of the basin. ## Worked examples ### Example 2 Air is pumped into a football. What shape does the air take? Working: 1. A gas takes the shape of its container. 2. The container is the football. 3. The air fills the ball and matches its shape. Answer: The air takes the shape of the football. ## Activity: Test shape with water and a stone You will need: A small stone, Water, A cup, A wide plate or lid, A balloon for each learner 1. Put the stone in the cup, then on the plate. Draw its outline each time and discuss whether the shape changed. 2. Pour the same water into the cup, then onto the plate. Draw the outline of the water each time. 3. Each learner inflates their own balloon only. Observe the shape of the air inside. Do not share balloons. 4. Write one sentence for the shape of a solid, a liquid and a gas. 5. Empty the water onto plants if it is clean, and wash your hands. PAGE 12: Lesson 4: Shape of solids, liquids and gases — Answers to practice ## Practice 1. Which state of matter has a definite shape? 2. What happens to the shape of milk when it is poured from a packet into a glass? 3. Why does air have no shape of its own after a balloon bursts? ## Answers to practice 1. Solid. 2. The milk takes the shape of the glass. 3. A gas spreads out to fill the space around it and does not keep the balloon's shape. ## Summary • Shape is a property of matter. • Solids have a definite shape. • Liquids and gases take the shape of their container, and a gas fills the whole container. LESSON 5: VOLUME OF THE THREE STATES ==================================== ## What you will learn • Explain the meaning of volume. • Describe the volume of a solid, a liquid and a gas. Curriculum outcomes: b) describe the properties of the three states of matter ## Introduction Fill a cup with water to the brim, then pour that water into an empty bottle. The water looks different, but it still fills the same amount of space. That amount of space is the volume. ## Notes Volume is the amount of space that matter occupies. We measure the volume of liquids in millilitres (ml) and litres (l). One litre is the same as 1,000 millilitres. A measuring jar or a marked bottle helps us read the volume. ### Liquids have a definite volume A definite volume means the amount of space stays the same even when the shape changes. If you pour 250 ml of water from a tall glass into a wide bowl, a measuring jar still shows 250 ml when you pour it back. You have not added or removed water, so the volume does not change. The same is true of milk, oil and juice. ### Solids have a definite volume A stone occupies the same amount of space on the table as it does inside a box. You do not need to melt it or pour it. Its volume stays the same as long as you do not break pieces off or add pieces on. Two identical bricks occupy twice the space of one brick. PAGE 13: Lesson 5: Volume of the three states — Gases have no definite volume ### Gases have no definite volume A gas spreads to fill whatever container it is in. A small amount of air pumped into a balloon occupies the balloon. If that air escapes into the classroom, it spreads through the whole room. You can also squeeze a gas into a smaller space: a bicycle pump pushes air into a smaller volume inside a tyre. Because a gas can be squeezed and can spread, it does not have one fixed volume. When you compare the three states, solids and liquids have a definite volume. Gases do not. [DIAGRAM] TYPE: svg ALT: Pouring changes the shape of water but not its volume PAYLOAD: CAPTION: Pouring changes the shape of water but not its volume [/DIAGRAM] ## Key words • volume — the amount of space that matter occupies • millilitre — a small unit used to measure the volume of a liquid • litre — a unit of volume; 1 litre is equal to 1,000 millilitres ## Worked examples ### Example 1 A learner measures 200 ml of juice in a jug and pours it into a glass. How much juice is in the glass? Working: 1. Juice is a liquid. 2. Liquids have a definite volume. 3. Pouring changes the shape, not the volume. Answer: 200 ml ## Worked examples ### Example 2 Air from a small balloon is released into a large empty room. What happens to the volume the air occupies? Working: 1. A gas has no definite volume. 2. It spreads to fill the space available. 3. The room is larger than the balloon. Answer: The air spreads out and occupies the volume of the room. PAGE 14: Lesson 5: Volume of the three states — Answers to practice ## Activity: Measure volume before and after pouring You will need: Measuring jar or a bottle marked in millilitres, Water, A cup, A wide bowl, A small stone 1. Pour water into the measuring jar and read the volume. Record it. 2. Pour that water into the cup, then into the wide bowl. Talk about the shape each time. 3. Pour the water back into the measuring jar and read the volume again. Compare the two readings. 4. Place the stone in a box and then on the table. Discuss whether its volume changed. 5. With a partner, write one sentence about the volume of a solid, a liquid and a gas. ## Practice 1. What is volume? 2. Which two states of matter have a definite volume? 3. 300 ml of water is poured from a bottle into a basin. What is the volume of the water in the basin? 4. Why does a gas not have a definite volume? ## Answers to practice 1. Volume is the amount of space that matter occupies. 2. Solids and liquids. 3. 300 ml 4. A gas spreads to fill its container and can also be squeezed into a smaller space. ## Summary • Volume is the space matter occupies. • Solids and liquids have a definite volume. • Gases have no definite volume because they spread and can be squeezed. PAGE 15: Lesson 6: Mass of solids, liquids and gases — Solids have mass LESSON 6: MASS OF SOLIDS, LIQUIDS AND GASES =========================================== ## What you will learn • Explain the meaning of mass. • Show that solids, liquids and gases all have mass. Curriculum outcomes: b) describe the properties of the three states of matter ## Introduction Lift an empty school bag, then lift the same bag after you have packed your books. The bag is harder to lift the second time because you have added matter. The amount of matter is the mass. ## Notes Mass is the amount of matter in a substance or object. Every state of matter has mass, because every state is matter. A heavier feeling usually means more mass, though the correct way to compare mass is to measure it. We measure mass with a beam balance or a weighing scale. Common units are the gram (g) and the kilogram (kg). One kilogram is equal to 1,000 grams. A mathematics lesson on measuring helps you read these units. ### Solids have mass A stone, a book and a metal spoon all have mass. A big stone has more mass than a small pebble of the same kind. You can compare them by placing one on each side of a beam balance. The side that goes down has more mass. ### Liquids have mass An empty bottle has less mass than the same bottle filled with water. The extra mass is the mass of the water. Milk, oil and juice have mass too. This is why a full jerrycan is harder to carry than an empty one. ### Gases have mass Air has mass, even though it is invisible. A balloon full of air has a little more mass than the same balloon when it is empty. A full cooking-gas cylinder has more mass than the same cylinder when the gas has been used up. The difference is the mass of the gas. Do not try to weigh a hot sufuria or a cylinder that is leaking. Tell an adult if you smell gas. Use your own balloon if you compare the mass of air, and do not share it. PAGE 16: Lesson 6: Mass of solids, liquids and gases — Compare mass of the three states ## Key words • beam balance — an instrument that compares or measures mass • gram — a unit used to measure mass • kilogram — a unit of mass equal to 1,000 grams ## Worked examples ### Example 1 An empty bottle is placed on one side of a beam balance and the same bottle full of water on the other side. Which side goes down, and why? Working: 1. The full bottle contains water as well as the bottle. 2. Water is matter, so it has mass. 3. The side with more mass goes down. Answer: The side with the bottle full of water goes down because the water adds mass. ## Worked examples ### Example 2 A cooking-gas cylinder feels lighter after many meals have been cooked. What has changed? Working: 1. Cooking uses gas from the cylinder. 2. Gas is matter and has mass. 3. When some gas has left, the cylinder has less mass. Answer: Some gas has been used, so the mass of the cylinder has decreased. ## Activity: Compare mass of the three states You will need: A beam balance or a ruler balanced on a pencil, A stone and a smaller pebble, Two similar empty bottles, Water, Two similar balloons 1. Compare the stone and the pebble on the balance. Record which has more mass. 2. Compare an empty bottle with a bottle of water. Say what the water adds. 3. Each learner uses their own balloon. Compare an empty balloon with a balloon blown up by that same learner. Do not share balloons. 4. Discuss how the activity shows that solids, liquids and gases have mass. 5. Put the materials away and wash your hands. ## Practice 1. What is mass? 2. Name the instrument used to measure mass. 3. Why is a jerrycan of water harder to carry than the same jerrycan when it is empty? 4. Do gases have mass? Give one example. ## Answers to practice 1. Mass is the amount of matter in a substance or object. 2. A beam balance (or a weighing scale). 3. The water has mass, so the full jerrycan has more mass. 4. Yes. Air in a balloon, or gas in a cooking-gas cylinder, has mass. ## Summary • Mass is the amount of matter in an object. • Solids, liquids and gases all have mass. • A beam balance measures mass in grams or kilograms. PAGE 17: Lesson 7: Comparing the properties of the three states LESSON 7: COMPARING THE PROPERTIES OF THE THREE STATES ====================================================== ## What you will learn • Describe shape, volume and mass for each state of matter. • Use the properties to classify a substance. Curriculum outcomes: a) categorise substances in the environment into the three states of matter; b) describe the properties of the three states of matter ## Introduction You now have three questions you can ask about any substance: What is its shape? What is its volume? Does it have mass? Putting the answers side by side shows how solids, liquids and gases differ. ## Notes The properties of matter in this sub-strand are shape, volume and mass. All three states have mass. Shape and volume are what make the states different. ### Solids A solid has a definite shape and a definite volume. A brick looks the same and occupies the same space wherever you place it, and it has mass. Solids do not need a container to hold their shape. They do not flow in the way water flows. ### Liquids A liquid has a definite volume but no definite shape. It takes the shape of the container. It has mass. A liquid flows and can be poured, and its surface stays level when the container is still. It needs a container if you want to carry it without spilling. ### Gases A gas has no definite shape and no definite volume. It fills the whole container and can be squeezed into a smaller space. It has mass. A gas spreads quickly if it is released. Most gases are invisible, so we notice them by the space they fill, the mass they add, or the way they move, as when wind blows. PAGE 18: Lesson 7: Comparing the properties of the three states — Properties table ### Using the properties to classify If a substance keeps its shape and its volume, call it a solid. If the volume stays the same but the shape changes to match the container, call it a liquid. If it spreads to fill any space and can be squeezed, call it a gas. Then check that it has mass, which all matter has. You can search a book or a safe digital source with your teacher for more characteristics, such as how easily each state flows. Write the facts in your own words and compare them with what you observed in class. ## Key words • definite volume — a volume that stays the same when the substance is moved to a new container • characteristic — a feature that describes something, such as the shape of a solid ## Worked examples ### Example 1 A substance takes the shape of any bottle it is poured into, but a measuring jar shows the same volume each time. It also has mass. Which state is it? Working: 1. It has no definite shape, so it is not a solid. 2. It has a definite volume, so it is not a gas. 3. It has mass, like all matter. Answer: It is a liquid. ## Worked examples ### Example 2 Complete the comparison: solids have a definite shape; liquids and gases do not. Which states have a definite volume? Working: 1. Solids keep the same volume. 2. Liquids keep the same volume when poured. 3. Gases spread and can be squeezed, so their volume is not definite. Answer: Solids and liquids have a definite volume. Gases do not. ## Activity: Properties table You will need: Manila paper, A stone, A bottle of water, A balloon, A textbook or a digital device used with the teacher 1. Draw a table with the headings Property, Solid, Liquid and Gas. 2. Rows: Shape, Volume, Mass. Fill the table from your experiments. 3. Demonstrate each property again with the stone, the water and the balloon. Each learner uses only their own balloon. 4. Use a book or a digital search, with your teacher, to check one extra characteristic of each state. Write it in your own words. 5. Present the table to another group. ## Practice 1. State the shape and volume of a solid. 2. State the shape and volume of a gas. 3. Which property is shared by solids, liquids and gases? 4. A substance fills the whole bottle and can be squeezed into a smaller space. Which state is it? ## Answers to practice 1. A solid has a definite shape and a definite volume. 2. A gas has no definite shape and no definite volume. 3. They all have mass. 4. Gas. ## Summary • Solids have a definite shape and a definite volume. • Liquids have a definite volume but no definite shape. • Gases have no definite shape and no definite volume. All three states have mass. PAGE 19: Lesson 8: Importance of the three states in daily life — Why gases are important LESSON 8: IMPORTANCE OF THE THREE STATES IN DAILY LIFE ====================================================== ## What you will learn • Explain how solids, liquids and gases are used in daily life. • Appreciate why each state of matter is important. Curriculum outcomes: c) appreciate the importance of the different states of matter in day-to-day life ## Introduction Think through one morning at home. You sit on a wooden stool, drink water, and breathe air before you leave for school. Those three actions use a solid, a liquid and a gas. ## Notes Each state of matter does jobs that the other states cannot do as well. Knowing this helps us use matter wisely and respect the materials around us. ### Why solids are important Solids keep their shape, so we use them to build and to make tools. Stones, bricks and timber make houses and classroom walls. Wood and metal make desks, spoons, pangas and cooking pots. Clothes, books and shoes are solids. Foods such as maize grains, beans and bread are solids. Because a solid keeps its shape, a bridge stays firm and a cup can hold a drink. ### Why liquids are important Liquids flow, so they can be poured, drunk and used for washing. Water is used for drinking, cooking, bathing and watering crops. Milk gives the body nutrients. Blood, which is a liquid, moves food and oxygen around the body. Liquid medicines can be swallowed. Cooking oil is used in food. Without liquids, plants and animals cannot live. ### Why gases are important We breathe air, which is a mixture of gases. The oxygen in air keeps people and animals alive, and plants use air as they make food. Wind, which is moving air, dries clothes and can turn a windmill. Air inside a ball or a tyre makes it firm enough to use. Cooking gas is used to cook food in many homes. Plants and animals also give out gases as part of living. ### Using each state well We should not waste water, because it is a liquid we all need. We should not pollute the air with smoke from burning rubbish. We should take care of solid materials so that furniture and buildings last. When you name the state of something you use, you also see why it matters. ## Key words • oxygen — a gas in air that people and animals need for breathing • appreciate — to understand the value of something and treat it as important PAGE 20: Lesson 8: Importance of the three states in daily life — Example 1 ## Worked examples ### Example 1 A family cooks supper using a metal sufuria, water and cooking gas. Name the state of matter used for each item and one reason it is useful. Working: 1. The sufuria is a solid. It keeps its shape and holds the food. 2. Water is a liquid. It flows and is used in cooking. 3. Cooking gas is a gas. It burns and provides heat. Answer: Sufuria: solid, holds the food. Water: liquid, used for cooking. Cooking gas: gas, provides heat. ## Worked examples ### Example 2 Why is air an important gas for people and for plants? Working: 1. People and animals breathe oxygen from the air. 2. Plants use air when they make food. 3. Without air, people, animals and plants cannot live. Answer: People and animals need air to breathe, and plants use air to make food. ## Activity: States of matter in a day You will need: Exercise book, Pictures from a book, newspaper or a digital device used with the teacher 1. Discuss in a group how you used a solid, a liquid and a gas since you woke up. 2. Make a chart with three columns: Solid, Liquid and Gas. List uses under each. 3. Search a book or a safe website, with your teacher, for one more use of each state. Write it in your own words. 4. Present the chart and say why we should not waste water or pollute the air. 5. Display the chart in the classroom. PAGE 21: Revision quiz ## Practice 1. Give two uses of solids in daily life. 2. Give two uses of water as a liquid. 3. Why is the air we breathe important? 4. Name one solid, one liquid and one gas you use when cooking a meal. ## Answers to practice 1. Any two, such as building houses, making tools and furniture, clothing, or solid food. 2. Any two, such as drinking, cooking, washing, or watering crops. 3. Air contains oxygen, which people and animals need to stay alive. 4. Examples: a sufuria (solid), water or oil (liquid), and cooking gas or air (gas). ## Summary • Solids keep their shape, so they are used for building, tools, clothes and many foods. • Liquids are used for drinking, cooking, washing and keeping living things alive. • Gases such as air and cooking gas are used for breathing, drying and cooking. REVISION QUIZ ============= Answer all the questions, then mark yourself on the Answers tab. 1. What is matter? A. Anything that occupies space and has mass B. Only things we can see C. Only solids and liquids D. Light and sound 2. Which list names the three states of matter? A. Hard, soft and wet B. Solid, liquid and gas C. Heavy, light and hot D. Stone, water and wood 3. Which substance is a gas? A. A coin B. Honey C. Air in a ball D. A dry leaf 4. Salt can be poured from a packet. Salt is a: A. gas B. liquid C. solid D. shadow 5. Which state of matter has a definite shape? A. Gas only B. Liquid only C. Solid D. Neither solid nor liquid 6. 200 ml of water is poured from a jug into a plate. What is the volume of the water now? A. Less than 200 ml B. More than 200 ml C. 200 ml D. The water no longer has volume 7. Which statement about mass is correct? A. Only solids have mass B. Gases have no mass C. Solids, liquids and gases have mass D. Mass is the shape of an object 8. A substance fills the whole container and spreads out when the container is opened. It has mass. Which state is it? 9. Why are liquids important in daily life? 10. Give one use of a solid and one use of a gas in daily life. PAGE 22: Quiz answers ANSWERS ======= 1. A. Anything that occupies space and has mass Matter occupies space and has mass. Air is matter even though we cannot see it. Light and sound are not matter. 2. B. Solid, liquid and gas The three states are solid, liquid and gas. Stone and wood are both solids. 3. C. Air in a ball Air spreads to fill the ball. A coin and a dry leaf are solids. Honey is a liquid. 4. C. solid Each grain of salt is a tiny solid that keeps its own shape. 5. C. Solid A solid keeps its shape unless it is broken or bent. Liquids and gases take the shape of the container. 6. C. 200 ml A liquid has a definite volume. Pouring changes the shape, not the amount of space the water occupies. 7. C. Solids, liquids and gases have mass Mass is the amount of matter. All three states are matter, so all three have mass. 8. Gas A gas has no definite shape or volume. It fills the container and has mass. 9. Liquids such as water are used for drinking, cooking, washing and watering crops. Because liquids flow, we can pour them and drink them. Living things need water. 10. A solid such as timber is used to build or make furniture. A gas such as air is used for breathing, or cooking gas is used for cooking. Solids keep their shape, so they make buildings and tools. Gases are used for breathing and for cooking.