States of Matter and Changes

The Three States of Matter#

Everything around you is made of matter — your desk, the air you breathe, the water you drink, even you! Matter is anything that takes up space and has mass. Scientists organize matter into three main states: solid, liquid, and gas.

Solids#

A solid has a definite shape and a definite volume (amount of space it takes up). The tiny particles that make up a solid are packed tightly together and vibrate in place — they don't flow or move around freely.

Examples: ice cube, rock, wood, a book, an apple

Properties of solids:

• Hold their shape
• Cannot be easily compressed (squeezed)
• Particles are very close together

Liquids#

A liquid has a definite volume but NO definite shape — it takes the shape of whatever container it is poured into. The particles in a liquid are close together but can slide past each other, which is why liquids flow.

Examples: water, juice, honey, lava, mercury in a thermometer

Properties of liquids:

• Flow and pour
• Take the shape of their container
• Cannot be easily compressed

Gases#

A gas has NO definite shape AND NO definite volume — it expands to fill whatever container it is in. The particles in a gas are very spread out and move quickly in all directions.

Examples: air, water vapor (steam), helium in a balloon, carbon dioxide

Properties of gases:

• Can be compressed
• Expand to fill any container
• Particles are far apart and move freely

Matter Is Everywhere!#

Look around you right now. The hard floor is a solid. The water in your bottle is a liquid. The air around you is a gas. Even though you cannot see most gases, they are definitely there — you are breathing gas (air) right now!