The thermometer is a medical instrument used to measure body temperature, the long head and short head of the use of the same basic, the results are the same, but the long head is more suitable for oral or armpit measurement, so that the surface of the mercury and the body of the contact surface is broader, more conducive to shorten the measurement time. The short head is more suitable for measurement through the anus, can be more effective to avoid thermometer rupture or damage to the anal mucosa. The mercury thermometer is a type of thermometer made of glass with a column of mercury that rises with body temperature. It is widely used in the medical field and in ordinary homes, and is usually available at drugstores.
Considering the dangers of mercury in mercury thermometers, many countries have banned them, with Sweden banning the sale of all mercury-containing medical devices as early as 1992.