A thermometer is placed in water in order to measure the water’s temperature. What would cause the liquid in the thermometer to drop?

A. The molecules in the water spread apart.
B. The molecules in the thermometer’s liquid spread apart.
C. The kinetic energy of the water molecules decreases.
D. The kinetic energy of the thermometer’s liquid molecules increases.

The molecules in the thermometer's liquid spread apart would cause the liquid in the thermometer to drop.

Option: B

Explanation:

When placing a thermometer in liquid to assess temperature of the water. The particles in the thermometer's liquid, which is often mercury, spread and rise, reflecting a boost in thermometer temperature. As hot, the liquid molecules in the thermometer travel faster, allowing them to separate themselves a little more. This contributes in the thermometer being powered up.  When cooled, the liquid molecules in the thermometer move more slowly, allowing them to come together a little closer. This leads to motion through the thermometer.