The change of state from a gas to a liquid. Condensation works by turning the water vapour within the air into a modification of liquid water. In other words, the water within the air, a gas called water vapour, from your hot shower cooled when it met the surface of the cold mirror. This resulted in the water vapour to condense, or become its liquid form. You realize this change as moisture or beads of water and fog that are prevalent in the mirror. It is also acceptable to consider condensation in terms of being the other of evaporation, or the method of a liquid converting into a gas. This occurs when a pot of water is boiled on the stove. The steam, another kind of water vapour, and bubbles you see within the boiling pot of water are proof of the liquid becoming gas.