1. solid to liquid = melting (heat energy added) e.g. ice melts to water
2.. liquid to solid = freezing (heat energy removed) e.g. water freezes to ice
3. gas to liquid = condensation (heat energy removed) e.g. cloud to rain
4. liquid to gas = vaporization (heat energy added) e.g. water to water vapour
5.solid to gas = sublimation (heat energy added) e.g. dry ice (frozen CO2) to carbon dioxide
6. gas to solid = deposition (heat energy removed) e.g. water vapour to frost