Solids, Liquids, and Gases

Everything around you is made of matter. Matter comes in three main forms called states: solid, liquid, and gas. The difference between them is how the tiny particles inside are moving. In a solid, particles are packed tightly. In a liquid, they slide around. In a gas, they fly freely.

Solids and Liquids

Solids have a definite shape and size. Their particles are packed closely together and vibrate in place. Rocks, books, and ice are all solids. Liquids have a definite volume but take the shape of their container. Their particles slide past each other. Water, juice, and oil are liquids.

Gases

Gas particles move quickly and spread out to fill any space they are in. They have no definite shape or volume. The air around you is made of gases. Steam from a boiling pot is water in its gas form. If you open a bottle of perfume, the gas particles spread through the room so everyone can smell it.

Fun Facts

• Water is the only common substance found naturally in all three states on Earth.
• A fourth state of matter called plasma exists in stars and lightning bolts.
• Gases can be squeezed into a much smaller space, but liquids and solids cannot.

Did You Know?

Glass might look solid, but some scientists have debated whether it is actually a super-slow-moving liquid. In reality, glass is an amorphous solid, which means its particles are arranged in an unusual way that is different from crystals!