Pour it into a different container

About this video

Nearly all the stuff around you comes in one of three forms, called the states of matter: solid, liquid or gas. The easiest way to tell them apart is to put each one into a different container and watch what it does.

A solid keeps its own shape. Move a wooden block from a tall glass into a wide bowl and it is still the same block. You can't pour it, and you can't squeeze it into a smaller space.

A liquid takes the shape of its container, but keeps its amount. Pour a litre of water from a tall glass into a wide bowl and it spreads out flat at the bottom. Pour it back and you get the same litre.

A gas fills whatever container it is in. Open a door into a bigger space and the gas spreads out to fill all of it. It has no shape of its own and no fixed amount of space: you can squeeze it into a smaller space, which is why a closed bottle of air squeezes in easily but a bottle of water hardly squeezes at all.

Some things look like they break the rules. Sand can be poured, but it is not a liquid: each grain of sand is a tiny solid that keeps its own shape, and a heap only flows because the grains roll over each other. Honey and toothpaste are slow, but they are liquids: give them time and they take the shape of their container.

Transcript

1. 0:00Solid, liquid or gas. Put each one in a different container and watch.
2. 0:08Move a block from a tall glass to a wide bowl. It keeps its own shape.
3. 0:17Pour water across. It takes the shape of the bowl, but it is still one litre.
4. 0:27Open a door, and a gas fills the whole space. Squeeze it, and it fits in less.
5. 0:36Sand pours, but it is not a liquid. Every grain is a tiny solid.
6. 0:45Keeps its shape, takes its container's shape, or fills it.