Question

Why is the freezing chest in a refrigerator fitted near its top?

Answer 1

Hint: Warm material that is lighter (less dense) rises, while cooler material that is heavier (more dense) sinks due to convection currents. It indicates that the refrigerator’s warm air rises from below while the cooler air lowers from the freezing chest.

Complete answer:
The compressor in the refrigerator begins to contract the refrigerant chemical vapor which leads to an increase in its pressure. This compressed gas is expelled via the coils outside the refrigerator. When this warm air comes into touch with cold air, it condenses and becomes a liquid. This cold liquid flows inward under tremendous pressure, cooling the air inside the refrigerator. By traveling below, cool air forms convection current, with hotter air moving higher towards the freezer.

The freezing chest in a refrigerator is placed near the top because it uses a convection current to cool the refrigerator's remaining area. The air close to the top gets in touch with the ice chest, cools, densifies, and lowers, whereas hot air from the lower half rises, causing convection currents to cool the entire space within.

Hence, the freezing chest in a refrigerator is fitted near its top.

Note: Convection is a heat transfer process that occurs solely in the case of liquids and gases. The free movement of molecules in such forms of matter is the reason behind this. Convection can only transfer heat energy whenever the temperatures of the two portions of the fluids are significantly different.