Superheating
In physics, superheating (sometimes referred to as boiling delay) is the phenomenon that a liquid can be heated to a temperature higher than its boiling point without actually boiling. This can happen because gas bubble formation at the normal boiling temperature can only occur in the presence of seeds in the form of small particles or gas bubbles. This can result in the liquid boiling very suddenly and violently—a very dangerous situation. Superheating is sometimes a concern with microwave ovens, some of which can quickly heat water without physical disturbance. A person agitating a container full of superheated water by attempting to remove it from a microwave will likely be scalded.