Deposition is a process in which a gas changes directly to a solid without going through the liquid state. It is the opposite of sublimation, which is when a solid turns directly into a gas, skipping the liquid phase. Deposition occurs when gas particles become very cold, and it is an exothermic process.

One common example of deposition is when water vapor in the air contacts a very cold windowpane, and the water vapor changes to tiny ice crystals on the glass, forming frost. Carbon dioxide is another example of a material that easily undergoes deposition.

In summary, deposition is a phase change in which a gas changes directly to a solid, bypassing the liquid phase. It occurs when gas particles become very cold, and it is an exothermic process. One common example of deposition is the formation of frost on a cold windowpane.