Year 4 Science: Gases
Part of the Year 4 Science solids, liquids and gases chapter. Chapter overview · whole chapter on one page
Gases
A gas has no fixed shape. It spreads out to fill any container it is in. Gases are easy to squash, unlike solids.
Air is a gas. The bubbles in fizzy water are a gas called carbon dioxide.
Key ideas
- A gas spreads out to fill its container.
- A gas has no fixed shape.
- A gas can be squashed, but a solid is hard to squash.
- Air and the bubbles in fizzy water are gases.
Method. Think about a balloon.
- Think about the balloon. The air in a balloon spreads out to fill the whole balloon.fills the whole balloon
- Decide. So a gas fills the whole container, and the answer is yes.yes
- Write the answer. yes
Check. Gases spread out to fill the space. ✓
Method. Read the chapter.
- Read the chapter. The bubbles in fizzy water are a gas called carbon dioxide.carbon dioxide
- Name the gas. So the gas in the bubbles is carbon dioxide.carbon dioxide
- Write the answer. carbon dioxide
Check. Bubbles rise because they are a gas. ✓
Method. Think about which one spreads out.
- Look at each one. Ice keeps its shape, but air spreads out to fill a container.spreads out
- Name the gas. So air is the gas.air
- Write the answer. air
Check. Ice is a solid, and air is a gas. ✓
Watch out
Watch out: you cannot see air, but it is still a material. Air is a gas, and it has weight. A gas is not “nothing”.
Try it at home or school (with a grown-up). Blow up a balloon with a grown-up, and feel the air inside it. Let it go and see which way the air rushes. Do not put a balloon in your mouth, and keep balloons away from small children.
Exam tip
Grown-up tip. Ask: “Can you see the air? Where does the air go in the balloon?” Let your child use the words gas and spreads out.
Exercise 6C Gases
Method. Think about which one spreads out.
- Look at each one. Air spreads out, but ice keeps its shape.spreads out
- Write the answer. air
Check. Ice is a solid. ✓
Method. Read the key idea in section 6.3.
- Read the key idea. A gas spreads out to fill its container.fill its container
- Write the answer. yes
Check. A balloon fills with air. ✓
Method. Read the chapter.
- Read the chapter. The bubbles in fizzy water are carbon dioxide.carbon dioxide
- Write the answer. carbon dioxide
Check. Carbon dioxide is a gas. ✓
Method. Read the key idea in section 6.3.
- Read the key idea. Gases can be squashed, unlike solids.squashed
- Write the answer. yes
Check. A balloon can be squashed by hand. ✓
Method. Read the key idea in section 6.3.
- Read the key idea. A gas has no fixed shape.no fixed shape
- Write the answer. no
Check. A gas takes the shape of whatever it fills. ✓
Method. Read the key idea in section 6.3.
- Read the key idea. A gas spreads out to fill its container.fill
- Write the answer. fill
Check. A gas fills the whole space. ✓
Method. Read the chapter.
- Read the chapter. The bubbles in fizzy water are a gas called carbon dioxide.a gas
- Write the answer. yes
Check. The bubbles rise because they are a gas. ✓
Method. Think about what Ali blows in.
- Think about the balloon. Breath is air, and it fills the balloon.breath
- Name the material. So the balloon is filled with air.air
- Write the answer. air
Check. Air is a gas that spreads out in the balloon. ✓
Method. Think about a gas in a container.
- Think about the gas. A gas spreads out to fill the container, so it has no flat surface like a liquid.spreads out
- Decide. So Ruby is not right.no
- Write the answer. no
Check. A flat top is a feature of a liquid. ✓
Method. Think about a gas in a liquid.
- Think about the bubbles. The bubbles are a gas that rises through the liquid.rises
- Make the prediction. So the bubbles should escape into the air and the drink goes flat.escape
- Write the answer. Accept any prediction that says the bubbles will rise and escape into the air, or the fizz will go down.
Check. Test with a grown-up, and watch the bubbles. ✓
Method. Think about the gas and the solid.
- Think about the gas. A gas has space in it, so it can be squashed.space
- Think about the solid. A solid keeps its shape and is hard to squash.hard to squash
- Write the answer. Accept any sentence that says a gas has space in it, so it can be squashed, while a solid keeps its shape and is hard to squash.
Check. The two states behave differently when squashed. ✓