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MEASUREMENT
Lesson 2 - Page 5

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Temperature is a physical property that reflects hotness or coldness of an object or space.  It is a measure of the energy that is released at a molecular level.  A thermometer is the standard way to measure temperature and is calibrated to a variety of scales in degrees (i.e., Celsius, Fahrenheit, Kelvin).  A thermometer uses a liquid that has a reasonable range freezing and boiling point that can be calibrated.  Most thermometers are either mercury or alcohol.  Since mercury is toxic, most of these thermometers have been banned for school use.  However, mercury is more precise.

Gabriel Fahrenheit in 1724 used mercury to create a thermometer.  Mercury is an ideal substance since it does not adhere to the glass and it remains liquid over a wide range of normal earthly conditions. Fahrenheit measured the boiling point of water to be 212 degrees and adjusted the freezing so it was 180 degrees from boiling (32 degrees). Temperatures measured on this scale are designated as degrees Fahrenheit (° F).

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