Water Cycle/Matter and Changes of State

Boiling

The process in which water gains heat and changes its state from liquid to gas at 100 degrees Celsius. Steam is produced during boiling. Boiling occurs throughout the whole liquid and can only occur at a fixed temperature.

Condensation

The process in which water vapour or steam comes into contact with a cooler surface, loses heat, and changes state from gas to liquid.

Evaporation

A process in which water gains heat and changes state from liquid to gas. Evaporation takes place only at the surface of the liquid and can take place at any temperature.

Freezing

A process in which water loses heat and changes state from liquid to solid at 0 degrees Celsius.

Melting

A process in which a solid gains heat and changes its state from solid to liquid. The temperature of the solid remains at 0 degrees Celsius until it has totally turned into liquid.