Types of fever thermometers
There are four different types of fever thermometers. They are distinguished by the technology they use to measure the body temperature.
A mercury fever thermometer is made of a narrow glass stem which is approximately 12.5cm long, with marking such as a Fahrenheit or Centigrade scale or in both along one or both sides. Liquid mercury is stored in a reservoir bulb at one end and rises through the capillary tube when brought in contact with a body. In modern clinical settings, mercury thermometers are prohibited because of the potential health hazards related to mercury. Mercury fever thermometers are banned in the European Union.
Infrared fever thermometers measure the body temperature with the help of an infrared sensor. It can be placed in the auditory channel of the ear, where the infrared sensor records the body heat radiated by the eardrum. It can also be moved over the forehead, concluding at the temple, to take the temperature. Infrared thermometers can also be called "tympanic" fever thermometers.
Disposable fever thermometers are plastic strips with dots on their surface. These dots are filled with temperature-sensitive chemicals, which change their color depending on the temperature level. This color change is the measuring scale of disposable fever thermometers. Usually, disposable thermometers have a sticky side used to put on the skin. This kind of thermometer is considered the most inaccurate in terms of measurement accuracy.