The electromagnetic spectrum is the range of all the different types of light waves that exist. This includes everything from radio waves (used for things like cell phones and radios) to microwaves (which heat up food) to infrared waves (which you feel as heat) to visible light (the colors we can see) to ultraviolet waves (which can give us sunburns) to x-rays (used in medicine to see inside our bodies) to gamma rays (which come from stars and are very dangerous). All of these waves have different properties and can be used in different ways. For example, doctors use x-rays to see inside our bodies without having to cut us open.