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
Medical thermometer be considered unpleasant, or embarrassing in some countries or cultures, especially if used on patients older than young children; also, if not taken the correct way, rectal temperature-taking can be uncomfortable and in some cases painful for the patient. Rectal temperature-taking is considered the method of choice for infants. The ear thermometer was invented by Dr. Theodor H. Benzinger in 1964. At the time, he was seeking a way to get a reading as close to the brain's temperature as possible, since the hypothalamus at the brain's base regulates the core body temperature. He accomplished this by using the ear