Temperature is the measure of the degree of hotness or coldness of a person or object. The word comes from the Greek word “tempera” which means heat. Temperature is recorded using a thermometer, which is usually a thin glass tube with mercury or colored alcohol inside the column. These old-style thermometers work on the principal of the mercury or alcohol expanding and moving up the column when the air around it heats up, and contracting and moving down the column when the air cools. The units on the scale used to measure temperature are called degrees. There are two different systems of measuring: Celsius and Fahrenheit.