Gas Expansion
How gases spread to fill all the space they're given.
What this lesson covers
Why it matters
Open a perfume bottle in one corner and soon the whole room smells of it. A gas doesn't sit still — it spreads to fill every bit of space.
Predict first
Put a little gas into a big sealed jar. What does it do?
A gas has no fixed shape or volume — its fast-moving particles spread to fill any container completely. A liquid takes the container's shape but keeps its volume; a solid keeps both.
- Spreads out to fill the whole jar — correct
- Sits in a small puddle at the bottom
- Sinks and disappears
What you do
Rank these by how much they spread to fill a container, most first.
Check yourself
A gas fills its whole container because its particles…
Fast-moving, far-apart gas particles spread out until they fill the space.
Pour a gas from a big jar into a small one. Its volume…
Gases have no fixed volume — they always fill whatever container holds them.
- move fast in every direction with big gaps between them — correct
- are sticky and clump together
- are too heavy to move
- changes to fit the new jar — correct
- stays exactly the same
- turns into a liquid