Freezing is the process when a liquid turns into a solid. Freezing occurs when heat is lost from an object, which causes the molecules to slow down and form tighter bonds. basically in short terms freezing is when, lets say, water turns into ice. Freezing is the opposite of melting, and two steps away from evaporation. Freezing occurs at below 0 degrees Celsius with water, while some other liquids become a solid at higher or lower temperatures.