Question

In order for your body to cool itself by sweating, what must happen after the sweat is emitted from your body?

Choose one:

A. The sweat absorbs heat from your body until it reaches its boiling point.

B. The sweat cools down and drips off.

C. The sweat absorbs heat from your body until it reaches its boiling point and it then changes into steam.

D. The sweat absorbs heat from your body and evaporates at room temperatu

Answer 1

(D) is the correct answer.

In order for sweat to cool your body temperature, the water must evaporate. If it drips off or if you wipe it off with a towel, you won’t benefit from the cooling mechanism of evaporation. Beads of sweat on your skin are in liquid form. When the water temperature rises, the molecules become more active and gain energy. When a molecule gains enough energy, it can break free from the bonds that hold the liquid together and transform into water vapor. This is evaporation. As the molecule evaporates, its energy -- or heat -- is removed from the sweat that remains on your body. This loss of energy cools the surface of your skin.