Infrared is a type of light that we cannot see with our eyes. Our eyes can only see what we call visible light. Infrared light brings us special information that we do not get from visible light. It shows us how much heat something has and gives us information about an object's temperature. Everything has some heat and puts out infrared light.
By using special infrared cameras, we can get a view of the infrared world. These cameras are very useful and have even helped save people's lives. In the infrared, you can "see" in the dark. Even if the Sun is down and the lights are off.