Thermometer consisting of mercury contained in a bulb at the bottom of a graduated sealed glass capillary tube marked in degrees Celsius or Fahrenheit; mercury expands with a rise in temperature causing a thin thread of mercury to rise in the tube
Alcohol thermometers may be used to measure temperatures from -115C (freezing point of alcohol) to 785C (boiling point of alcohol). The standard thermometer for environmental measurements need only cover the range -20F to 120F, or about -30C to 50C.