Why the pot boiling by pressure so that cooked food much faster than normal.
We are familiar with the evaporation of water. This evaporation means that the water will gradually change state from liquid to vapor. Molecules of water on the surface will jump up in the air. If water temperatures increase, then the jump will be more and stronger too. It is accelerate of evaporation, and strong jump will cause water molecules fall in the air. If the water is heated to 100 C., the water will boiling more and more steam but the temperature was still only 100 C. So in a boiling foods with ordinary boiler, so that the maximum temperature only 100 C. If we want to cook to be ripe sooner. We have sought to raise the temperature of boiling water. Which boiler by pressure can increase the temperature of boiling water very well.
We already know that the temperature of boiling water depending on pressure on the surface. If increased pressure, the water will boil at higher temperatures but if reduced pressure, the water will boil at lower temperatures. We put water and foods in a pressure boiler and tight lid on the pot so that no steam can escape. At this lid pot will have safety slot for cooling steam to keep pressure boiler as needed. For this reason, we can determine the pressure in the pot. When the pressure is much higher than normal, then temperatures in the boiler will be higher than 100 C.