Water can exist in three states: as a liquid, solid (ice and snow), or gas (water vapor). As a liquid, water takes the shape of its container and is what we drink, swim in, and wash with, filling lakes and rivers. Ice and snow are examples of water in its solid state. Water vapor is an invisible gas in the air, making up clouds and steam. Water changes between these states by gaining or losing heat through freezing, melting, evaporating, or condensing.