Dilatometer
![A simple structure of a dilatometer for the measurement of the thermal expansion of liquids and solids](/Images/godic/202501/09/Dilatometer3557.jpg")
A dilatometer is a scientific instrument that measures volume changes caused by a physical or chemical process. A familiar application of a dilatometer is the mercury-in-glass thermometer, in which the change in volume of the liquid column is read from a graduated scale. Because mercury has a fairly constant rate of expansion over normal temperature ranges, the volume changes are directly related to temperature.