Selecting a Mercury-Free Thermometer on Amazon.com
A mercury-free thermometer, also called a spirit thermometer or liquid-in-glass thermometer, is made of glass and filled with a liquid such as alcohol or other spirit. The liquid expands in response to heat and rises in the glass capillary tube to indicate a temperature. The liquid in a non-mercury thermometer is colored with red or blue dye for visibility. Each thermometer is etched with a temperature scale, typically either Fahrenheit or Celsius, though some have a dual scale. The glass capillary tube may be made of safety-coated glass to help contain glass and liquid in case of breakage. For mounting on a wall, a mercury-free thermometer may have a plastic case for protection. Mercury-free thermometers are commonly used in medical and veterinary care, scientific laboratories, chemical and pharmaceutical processing, dairies, breweries, and food processing facilities.