The coolest air is found at the bottom inside an oven
Explanation:
Inside an oven, the process that takes place is the convection of air (heat). In this process, the coolest air that are present at the bottom of the oven gets heated up, due to which it becomes warm and lighter, and eventually rises up towards the upper portion of the oven. As these warm air rises, it again cools and subsequently sinks to the bottom. These air is again heated and the cycle continues, thereby forms convection cells that allows the food items to get warm inside the oven.
Thus, the coldest air is found always at the bottom of an oven due to its higher density.
Air is a fluid. When a fluid is heated, such as in the oven, it undergoes convection: the part of the fluid which is heated more becomes less dense than the rest of the fluid (because the molecules move faster, so the separation between them increases), so it moves on top of the fluid, while the colder parts of the fluid, being more dense, move on bottom. Then the colder parts of the fluid are also heated, and they move on top, and this process continues: we say that a convective current is created.
As we just described, therefore, the colder parts of the air remain at the bottom, since they are more dense than the hotter air.
