Key Stage 2 · Year 3 · Science · 2 minutes
Solids, liquids and gases
Solids keep their shape. Liquids flow. Gases spread out.
Key terms
- particles
- Tiny bits that everything is made of, far too small to see.
- solid
- A state where particles are packed tightly and just vibrate on the spot, so it keeps its shape.
- liquid
- A state where particles are close but slide past each other, so it flows and takes the shape of its container.
- gas
- A state where particles are far apart and zoom around, so it spreads out to fill any space.
- melt
- To change from a solid to a liquid when heated.
- evaporate
- To change from a liquid to a gas when heated.
- condense
- To change from a gas to a liquid when cooled.
Transcript
Why does an ice lolly drip on a hot, sunny day? And where does a puddle go when the sun comes out?
Everything around you is a solid, a liquid or a gas. Your ice lolly is a solid. The juice dripping off it is a liquid. And the air all around you is a gas.
Everything is made of tiny bits called particles, far too small to see. So let's zoom in, really close!
In a solid, the particles are packed tightly together. They can't move around. They just vibrate on the spot, so a solid keeps its shape.
In a liquid, the particles are still close together, but they can slide past each other. So a liquid can flow, and it takes the shape of its container.
In a gas, the particles are far apart, zooming around in every direction. So a gas spreads out to fill any space it can find.
Now, watch what happens when we heat them up. Heat a solid, and it melts into a liquid. Heat the liquid, and it evaporates into a gas. Cool it back down, and it all goes backwards. The gas condenses into a liquid, and the liquid freezes into a solid.
That's why your ice lolly melts in the sun, and a puddle slowly evaporates into the air. And when steam from a kettle meets a cold window, it condenses into tiny drops of water.
So remember: solids keep their shape, liquids flow, and gases spread out. And heating or cooling can change one into another!
Sources
Every fact in the video, and where it comes from.
- 1educationquizzes.com/ks2/science/solids-liquids-and-gases-01/print
- Materials can be grouped as solids, liquids or gases; all are made of particles arranged differently in each state.
- 2simplestudy.com/gb/gcse/aqa/chemistry-combined-science/revisio…
- In a solid, particles are tightly packed and vibrate in fixed positions, so solids keep their shape.
- 3edu.rsc.org/download
- In a liquid, particles are close together but can slide past each other, so liquids flow and take the shape of their container.
- In a gas, particles are far apart and move quickly and randomly in all directions, spreading out to fill their container.
- 4educationquizzes.com/ks2/science/solids-liquids-and-gases-02
- Heating and cooling change state: melting (solid to liquid), evaporating (liquid to gas), condensing (gas to liquid), freezing (liquid to solid).
- 5curriculumvisions.com/search/C/condensation/condensation.html
- Steam from a kettle condenses into tiny water droplets when it meets cooler air or a cold surface.
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