What is Constant Volume Gas Thermometer?

An introduction to the constant gas volume thermometer and its use as a standard for other thermometers.Thermometers are working examples of the zeroth law of thermodynamics. The significance of constant volume gas thermometers is that they are used to calibrate other thermometers. A constant volume gas thermometer is composed of a bulb filled with a fixed amount of a dilute gas that is attached to a mercury manometer. A manometer is a device used to measure pressure.Gas Thermometer The mercury manometer has a column partially filled with mercury that is connected to a flexible tube that has another partially filled column of mercury, called a reservoir, attached to the other end.