Mercury-in-glass thermometer Mercury-in-glass thermometer The mercury-in-glass or mercury thermometer was invented by physicist Daniel Gabriel Fahrenheit in Amsterdam (1714). It consists of a bulb containing mercury attached to a glass tube of narrow diameter; the volume of mercury in the tube is much less than the volume in the bulb. The volume of mercury changes slightly with temperature; the small change in volume drives the narrow mercury column a relatively long way up the tube. The space above the mercury may be filled with nitrogen gas or it may be at less than atmospheric pressure, a partial vacuum. In order to calibrate
Liquid crystal thermometer and it is put onto someone's forehead it will change colour depending on the temperature of the person. There are two stages in the liquid crystals: Liquid crystal thermometers portray temperatures as colors and can be used to follow temperature changes caused by heat flow. They can be used to observe that heat flows by conduction, convection, and radiation. In medical applications, liquid crystal thermometers may be used to read body temperature by placing them against the forehead. These are safer than a mercury-in-glass thermometer, and may be advantageous in some patients, but do not always give an exact result,