Question

A student places a thermometer in hot water during a lab and the column of fluid inside the thermometer rises to 90 ° Celsius. What causes the change in the thermometers' readings?
Responses
A Entropy causes fluid in the thermometer to crystalize and expand.Entropy causes fluid in the thermometer to crystalize and expand.
B The hot water acts as a catalyst causing a chemical reaction in the thermometer.The hot water acts as a catalyst causing a chemical reaction in the thermometer.
C Radiation from the water causes fluid in the thermometer's bulb to push the fluid in the column higher .Radiation from the water causes fluid in the thermometer's bulb to push the fluid in the column higher .
D The heat of the water causes molecules in the thermometer's fluid to move faster, spread apart, and rise in the thermometer's column.

Answer 1

Answer: D.

Explanation: Heat from the hot water raises the temperature of the thermometer fluid, increasing the average kinetic energy of its molecules. The molecules move farther apart so the liquid expands; because the bulb is wider than the capillary, the expanding liquid is forced up the narrow column. This is thermal expansion, not a chemical reaction, crystallization, or primarily radiation.