91Ó°ÊÓ

A piece of aluminum foil is used to cover a potato so that we can bake it in a hot oven.

Heat can be described as energy transfer from one point to another where both points are at a different temperature; the value of transferred energy is known as heat.

Thermal conductors have the ability to fast heat up and cool down.

Reason 1: The body can not contain heat in them; that energy is transferred to another body. When the foil gets heated up, the potato is there to absorb the transferred heat, and its temperature increases, but as fast as the foil gets heated up, it also cools down at almost the same speed. Therefore after a few seconds, we can touch it, but the potato is still too hot to be touched.

Reason 2: The foil is made in the shape of a sheet. The sheet has a mass that is small and a large surface area, and it is made of an excellent thermal conductor, and the heat it can hold before transferring is very less. It radiates heat from its surface and in all directions., and cools down. On the other hand, potatoes have water content and few ions, and their shape is also similar to a round shape. It takes time for it to cool down. Thus after a few seconds, we can touch it, but the potato is still too hot to be touched.

Thus, a piece of aluminum foil used to wrap a potato for baking in a hot oven can usually be handled safely within a few seconds after the potato is removed from the oven. The same is not true of the potato because of the type of the foil, shape, and heat transfer from foil to potato, and the rest environment allows the foil to cool down way faster than the potato.