Solids, liquids and gases
Heat and cool a box of water particles and watch them shake as ice, slide as water and fly apart as steam.
Standards: 2-PS1-15-PS1-1
1Wonder
An ice cube, a glass of water and the steam from a kettle are all the same stuff: water. So why is one hard, one runny and one invisible in the air?
2Explore
This activity needs a bigger screen
Turn your phone sideways, or open this lesson on a tablet or computer. The explanation and quiz below work here.
- Start cold, below 0 °C. How do the particles move in ice?
- Warm it up past 0 °C. What happens to the ice? Where do the particles go?
- Keep heating past 100 °C. Where are the particles now?
- Turn on Follow one particle. Compare its path in ice, water and steam.
3Explain
Everything is made of particles
If you could zoom in far enough on an ice cube, you would see it is made of tiny particles, far too small to see. Water, steam and everything else are made of particles too, and they never stop moving.
Matter is made of tiny moving particles. Solid: packed, shaking in place, keeps its shape. Liquid: close, sliding past each other, flows. Gas: far apart, flying freely, fills its container. Heating speeds particles up; cooling slows them down.
4Practice
Which one keeps its own shape?
5Recap
- Everything is made of tiny particles that are always moving.
- Solid: particles packed and shaking in place. Liquid: close but sliding. Gas: far apart and flying.
- Heating speeds particles up (melting, boiling); cooling slows them down (condensing, freezing).
- Water melts at 0 °C and boils at 100 °C.