Everything is a solid, a liquid or a gas. Solids keep their shape, liquids flow and take the shape of their container, and gases spread out to fill any space. Heating and cooling can change one state into another.
What your child will learn
- Sort materials into solids, liquids and gases
- Describe the properties of each state
- Know that melting, freezing, evaporating and condensing change state
- Name some everyday gases, like oxygen and carbon dioxide
Tricky cases
Sand and sugar can be poured, but each grain is a tiny solid that keeps its shape — so they are solids. Gases are all around us even though most are invisible: we breathe in oxygen, and the bubbles in fizzy drinks are carbon dioxide.
Example questions
Here are a few questions like the ones in the first quest. Can you solve them?
1. Which of these is a gas?
- Air
- Water
- Sand
- Stone
Show answer
Answer: Air. Air is a mixture of gases.
2. Which gas do we breathe in to stay alive?
- Smoke
- Oxygen
- Helium
- Steam
Show answer
Answer: Oxygen. Our lungs take oxygen from the air.
3. What state is steam?
- Liquid
- Solid
- Gas
Show answer
Answer: Gas. Steam is water as a gas.
Tips for grown-ups
- Make ice lollies and watch them melt: solid to liquid.
- Pour water into different containers and notice how its shape changes.
- Blow up a balloon — you are filling it with gas.