# Fundamentals of Physics/Temperature

What is temperature? That is a very interesting question, and will be the topic of this chapter. The simple answer to this question is that temperature is the magnitude of heat in a system (how hot or cold it is), and heat is a measure of thermal energy that an object has, or how rapidly the particles (atoms and molecules) that make up the object are moving. The faster the motion, the hotter the object. So, the molecules in a glass of hot water are moving faster (and have a higher energy) than in a glass of water with ice (which would have a lower energy). As previously mentioned, temperature is just a measurement of the magnitude of this heat or cold.

Temperature is measured in degrees, and there are several different scales of measurement, but the most commonly used three are the Fahrenheit, Celsius, and Kelvin scales. In each of these system of measurement, a degree has a different value (one degree Celsius is a larger step than a degree Fahrenheit, and other such things as these), but, nonetheless, they all measure the same thing-the degree of heat or cold in a system.