pot top
Pot-top
pot top
pot top
Pot top
pot top
pot top
pot top
The liquid in the pan gets hot, and creates water vapor. The lid, blanketed by the outside air, is cooler than the liquid in the pan, so the water condenses on the underside of the lid.
A pan doesn't dry out when you put a lid on it because you are creating a closed environment. The lid traps the steam that results from the heat. The steam hits the lid and when it can go through it turns into condensation which puts the liquid back into the pan.
DO NOT throw water on the pan. Quickly get a lid onto the pan; that should extinguish the flames. Turn the burner off and wait for the pan to cool.
We had a stuck "glass cover lid" on a non-stick steel frying pan. We were frying hamburgers and tried to keep the grease from getting on our stove. We put the "glass cover lid" on the frying pan. Wrong move. We tried heating and cooling the "pan and cover" using many of the ideas on the Internet. Nothing worked. I finally got the "glass cover lid" off the "frying pan" by first cooling the "cover and pan" to room temperatures (I put the "cover and pan" in the refrigerator for a while after the cover and pan got to room temperature). I then put the pan on the stove and started heating up the bottom of the pan. At the same time that I am heating up the bottom of the pan, I am trying to pull off the cover. The steel pan started heating up. When the sides of the pan started to heat up, the cover poped off. The "glass cover lid" was still cool when the "glass cover lid" poped off. Some of the advice I saw before doing this was to put ice on the cover and heat the pan with hot water. I believed I created the same thing (i.e., expansion and contraction principle) using a different method. John Melin