It is a measurement of the intensity of the heat. This lesson will answer those questions and explain temperature to you. You have probably noticed that most materials expand when heated. The higher the temperature, the more things expand. That principle can be used to measure the temperature.
Many thermometers use the expansion of liquids in a tube to measure the temperature.
Fahrenheit invents thermometer Around 1700, a German scientist Gabriel Fahrenheit invented the thermometer by putting water in a glass tube. The warmer the temperature, the higher the water went up the tube. Now, to be able to measure temperature with numbers, Fahrenheit had to determine a unit of measurement. Fahrenheit defines units Fahrenheit used his body temperature as 100 degrees and the freezing temperature of saturated salt water as 0 degrees. He marked those levels on his thermometer and divided the scale into 100 parts for each degree.