Question

What type of expansion of mercury is used to calibrate a thermometer

Answer 1

i’m not sure “calibrate”is the proper word here, but the answer is volumetric thermal expansion.

For example mercury expands by volume 0.0182% per deg C. It is the ratio of the volume of the thermometer bulb to the volume/inch of capillary tube that determines how far the mercury rises in the tube per degree.

Alcohol expands 4.1 time more than mercury, so make a thermometer using alcohol, then the ratio between tube and bulb is 4.1 times smaller is you want the same sensitivity (distance between deg marks) to temperature change.

Answer 2

$\huge\mathrm{Answer}$

In order to calibrate the thermometer, the bulb is made to reach thermal equilibrium with a temperature standard such as an ice/water mixture, and then with another standard such as water/vapour, and the tube is divided into regular intervals between the fixed points