Lesson 2 of 7
The particle model
Goal: Explain the properties of each state using particles.
Everything is made of tiny particles. How they are arranged, and how they move, explains the way solids, liquids and gases behave.
The particles are the same in each box. Only their arrangement and their movement are different.
- Solid: the particles are packed close together in a regular pattern. They vibrate about fixed positions, so a solid keeps its shape.
- Liquid: the particles still touch, but in no pattern. They slide past each other, so a liquid flows.
- Gas: the particles are far apart and move fast in every direction. A gas fills its container, and it can be squashed because of the gaps.
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Key words in this lesson
Particle A tiny piece of matter, far too small to see
Particle model The idea that everything is made of tiny moving particles
Solid Has a fixed shape and a fixed volume
Liquid Flows and takes the shape of its container, but has a fixed volume
Gas Spreads out to fill its container, and can be squashed