States of Matter and Phase Changes

States of Matter

• Solids have a definite shape and volume. Their particles are tightly packed and only vibrate. Examples include ice and rock.
• Liquids have a definite volume but take the shape of their container. Their particles are close together but can move around each other. Examples include water and juice.
• Gases have no definite shape or volume and fill any container. Their particles are far apart and move freely. Examples include air and steam.

Phase Changes

• Condensation occurs when a gas cools down and turns into a liquid. An example is water droplets forming on a cold glass.
• Evaporation occurs when a liquid heats up and turns into a gas. An example is water drying up on a sunny day.
• Sublimation occurs when a solid turns directly into a gas without becoming a liquid. An example is dry ice (solid carbon dioxide) turning into gas.
• Melting occurs when a solid heats up and turns into a liquid. An example is ice melting into water.
• Freezing occurs when a liquid cools down and turns into a solid. An example is water turning into ice.