Superheating is a process that happens when water is heated up so much that it becomes steam. Water usually boils and turns into steam when it reaches 212 degrees Fahrenheit or 100 degrees Celsius. But if heat is added to the water under high pressure, it can get even hotter than its boiling point. This means that the water turns into steam without boiling.
Imagine you have a pot of water on the stove. You turn up the heat slowly, and soon enough, little bubbles start forming at the bottom of the pot. Those bubbles are pockets of water vapor that are escaping from the water and coming to the surface. As the heat continues to transfer from the stove, more and more bubbles form, until the entire pot is bubbling and boiling. The temperature of the water remains at 212 degrees Fahrenheit throughout the boiling process.
Now, let's say you have another pot of water, but this time, you put a lid on it and seal it tightly. Instead of increasing the heat slowly, you turn it up very quickly. You know how steam is generated when water is heated to a boiling point? So, because the lid is sealed and there is a high pressure building inside, the temperature of the water in the pot can rise much higher than 212 degrees Fahrenheit without boiling.
This is called superheating. The water in the pot has become "superheated" because it is hotter than the boiling point. When a small impurity, such as a speck of dust or tiny bubble, is introduced into the superheated water, the water can rapidly boil and turn into steam. This can happen very quickly and explosively, which can be very dangerous.
Therefore, superheating is a process in which water is heated above its boiling point, remaining in a liquid state. This highly pressurized water can violently boil when it is exposed to a small disturbance or foreign particle, which is why it is crucial to handle superheated water with extreme caution.