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.
Apa yang akan dipelajari anak anda
- 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.
Contoh soalan
Berikut ialah beberapa soalan seperti dalam misi pertama. Bolehkah anda menjawabnya?
1. Which of these is a gas?
- Air
- Water
- Sand
- Stone
Tunjuk jawapan
Jawapan: Air. Air is a mixture of gases.
2. Which gas do we breathe in to stay alive?
- Smoke
- Oxygen
- Helium
- Steam
Tunjuk jawapan
Jawapan: Oxygen. Our lungs take oxygen from the air.
3. What state is steam?
- Liquid
- Solid
- Gas
Tunjuk jawapan
Jawapan: Gas. Steam is water as a gas.
Tip untuk orang dewasa
- 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.