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Fever Thermometers

Fever thermometers measure human body temperature and may contain mercury. Fever thermometers are commonplace in homes and medical institutions, however sales of mercury-containing fever thermometers have been decreasing as safer alternatives increase in popularity.

How can I tell if my thermometer contains mercury?

ThermometerMercury may be found in fever, basal, and cooking thermometers.

  • Thermometers containing mercury can be easily identified by the colour of the material in the bulb. If the bulb is silver, the thermometer most likely contains mercury. However, new fever thermometers containing gallium, indium, and tin will also appear silver in color. These thermometers are marketed as "mercury-free" thermometers and should be clearly marked as such.
  • If your thermometer is filled with a red-tinted fluid, then it does not contain mercury. These types of thermometers are safer because if the glass vial breaks the alcohol fluid will simply evaporate.
  • ThermometerIf your thermometer has a dial, such as, candy thermometers, it uses a metal spring that is sensitive to heat. As the metal heats and expands, the spring slowly unwinds, driving the dial or arrow attached to one end of a spring. A thermometer that registers temperature with a round dial uses this type of mechanism and does not contain mercury.
  • Digital display thermometers do not contain mercury. This type uses a metal probe to sense temperature. Electronic components in the thermometer can take very accurate and fast temperature readings. They are also safe, since they can withstand temperature extremes without breaking.