Everything around us is made of matter — the water we drink, the air we breathe, even the table we write on. But did you know matter can change its form? In this lesson, we'll learn about the three states of matter.
Solid, Liquid, and Gas
A solid has a fixed shape and a definite size, like a rock, wood, or ice, and it only changes shape with outside force. A liquid has no fixed shape — it takes the shape of whatever container it's in — but its amount stays the same, like water, juice, or oil.
A gas has neither a fixed shape nor a fixed size, and it spreads out to fill any space it's in, like air or water vapor. In solids, particles are packed tightly together; in liquids, they're less tightly packed and move around more freely; in gases, they're spread far apart and move quickly in every direction.
Matter can change from one state to another. When we heat ice, it melts into liquid water, and if we keep heating the water, it turns into water vapor, a gas. When the vapor cools, it turns back into water, and if the water gets cold enough, it freezes into ice again. These changes happen because of temperature, and they're a great example of how matter can change form without losing what it fundamentally is.
- Solid: fixed shape and size, like ice and wood
- Liquid: fixed amount, changing shape, like water
- Gas: no fixed shape or size, like water vapor
- Temperature change moves matter from one state to another
