What is a gas?
A gas has no fixed shape or size. It spreads out to fill any container. The air we breathe is a mix of gases — mostly nitrogen and oxygen.
Particles in a gas
Particles in a gas move very fast in all directions and are spread far apart.
Gases have weight
Even though gases feel like 'nothing', they have mass. A balloon full of air weighs slightly more than an empty one!
🔑 Key Terms
- Gas
- A state of matter with no fixed shape or size.
- Particle
- A tiny bit of matter that everything is made from.
Did you know?
The air pushing on your body right now weighs about the same as a small car — but you don't feel it because it pushes equally from all sides!
Try it at home: Catch some air
- Hold an empty plastic bag and run with it open.
- Twist it shut quickly.
- You've trapped a gas — squeeze the bag and feel it push back!