For example, the physical properties of ice and steam are quite different but they are both water. There is no change in the chemical nature of the two substances. Phase changes include melting, freezing, condensation, evaporation, and sublimation. Melting occurs when a solid changes to a liquid. Freezing occurs when a liquid becomes a solid.
Condensation involves a gas becoming a liquid.
Evaporation involves a liquid becoming a gas and sublimation is the change of a solid directly to a gas. Look at the following examples and decide what phase change is involved. That's why water doesn't get hotter as it boils. The temperature remains constant until the phase change is complete. To better understand physical changes break a small piece off the bottom of a candle and describe 4 ways in which the candle has changed physically.