Year of Invention: 1714
What Is It? A device to accurately, quantitatively measure the temperature of
Who Invented It? Daniel Fahrenheit (in Amsterdam, Netherlands)
Whenever you’re sick, you take your temperature—with a thermometer. To decide what to wear, you check the temperature outdoors—on a thermometer. When baking, you use a thermometer to check the temperature of your oven. Our daily life depends on knowing the temperature. Temperature depends on thermometers.
Science depends on precise temperature measurement even more than the general public does. Accurate measurement of heat and temperature has been essential to the development of medical science, thermodynamics, physics, astronomy, chemistry, and meteorology.
Ancient people had no way to measure temperature other than by touch. However, humidity and wind both affect how hot a given temperature feels. There existed no reliable, accurate way to measure and compare temperatures.
In 1581, Galileo was the first to create a crude thermometer. From previous work, he knew that gasses (air) expanded when hot and contracted when cooled and planned to use expanding air as a way to measure temperature. He invented the word thermometer from the Greek words meaning “to measure heat.”
However, Galileo’s thermometer was monstrously inaccurate. Changes in air pressure (or in the water vapor trapped in the bulb’s air) changed the thermometer’s reading. It was unacceptable for scientific work.
Thirty-four-year-old Daniel Fahrenheit moved to Amsterdam from his native Germany to set up a plant to manufacture meteorological instruments. Fahrenheit regularly felt