1Three states of matter
Everything is made of tiny particles. In a solid they are packed in rows, in a liquid they slide around, and in a gas they fly about, far apart.
particlesolidliquidgas
Lesson 2.1 notes
Solids, liquids and gases
Everything is made of particles. How they are arranged and how they move explains solids, liquids and gases.
2Solids
Solid particles are held in place by strong forces. They vibrate but can't move around, so a solid keeps its shape.
vibrate
3Liquids
Liquid particles touch but can slide past each other, so a liquid flows and takes the shape of its container. Its volume stays the same.
flowvolume
4Gases
Gas particles are far apart and move fast in all directions, so a gas spreads out to fill its whole container.
spread out
5Squashing
Only a gas can be squashed: there are big spaces between its particles. Solid and liquid particles already touch.
compress
6Density
Density is how much mass is packed into a space. Solids and liquids are dense; gases have a very low density.
density
Explore: Particle lab
Switch between solid, liquid and gas, then try to squash each one.
Common mistake: The particles themselves don't change
A water particle is the same in ice, water and steam. Particles don't swell, shrink or melt: only their arrangement and movement change.
Remember
- Solid: packed in rows, vibrating. Liquid: touching, sliding. Gas: far apart, moving fast.
- A gas spreads out to fill its container, and it can be squashed.
- Between gas particles there is empty space.
Going further at GCSE