States of Matter
Grade 2 · Science · Study Guide
Everything around us is made of matter! Learn about the three states of matter and how they are different.
Matter is everything that takes up space and has weight. Look around you — the chair you sit on, the water you drink, and even the air you breathe are all matter! Scientists sort matter into three main states: solid, liquid, and gas.
A solid keeps its own shape. Rocks, books, and ice cubes are solids. A liquid flows and takes the shape of whatever container it is in. Water, juice, and milk are liquids. A gas spreads out to fill any space it is in. The air inside a balloon is a gas.
Matter can change from one state to another! When you heat ice, it melts into liquid water. When you heat liquid water enough, it turns into steam, which is a gas. This is really cool because it is still the same matter — just in a different state!
| State | Shape | Example |
|---|---|---|
| Solid | Keeps its own shape | Rock, ice, book |
| Liquid | Takes shape of container | Water, juice, milk |
| Gas | Fills all available space | Air, steam, breath |
Key terms
- matter
- Anything that takes up space and has weight
- solid
- Matter that keeps its own shape
- liquid
- Matter that flows and takes the shape of its container
- gas
- Matter that spreads out to fill any space
- melt
- When a solid changes to a liquid because of heat
- freeze
- When a liquid changes to a solid because of cold
Flashcards
- Solid
- Matter with its own shape, like a rock or ice cube
- Liquid
- Matter that flows and takes the shape of its container, like water
- Gas
- Matter that spreads out to fill any space, like air
- Matter
- Everything that takes up space and has weight
- Melt
- When a solid turns into a liquid (ice melting into water)
- Freeze
- When a liquid turns into a solid (water turning into ice)
Practice questions
Which of these is a solid?
- Milk
- Air
- A rock
- Steam
Show answer
Answer: A rock
Rocks keep their own shape, which is what makes them solids.
A liquid keeps its own shape no matter what container it is in.
Show answer
Answer: False
Liquids flow and take the shape of any container they are poured into.
When ice melts, it changes from a solid to a ___.
Show answer
Answer: liquid
Heat causes ice (solid) to melt and become liquid water.
What happens to water when it gets very cold?
- It becomes a gas
- It becomes a solid
- It disappears
- It becomes heavier
Show answer
Answer: It becomes a solid
Cold temperatures cause water to freeze and turn into ice, which is a solid.
Air is an example of a gas.
Show answer
Answer: True
Air is a gas because it spreads out and fills whatever space it is in.
Fun facts
- Water is the only substance on Earth that naturally exists as a solid, liquid, AND gas in everyday life!
- Your breath is a gas — you can see it on cold days as tiny water droplets in the air!
- Even rocks can become liquid if they get hot enough — that is what lava is!
Get a personalized course on States of Matter built around your child.