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

A. The molecules in the water move closer together.

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 decreases.

Option B

The molecules in thermometer spread apart

Explanation:

The mercury within the thermometer spread apart leading to an increase in temperature reading in the thermometer. The spreading apart of mercury molecules is caused by an increase in kinetic energy of molecules and with time the increase in kinetic energy decreases making the reading to stop increasing hence constant.