More about Photons and Light

Light is energy people can see. There are also kinds of energy which are invisible to people's eyes. Such as:

infrared - this energy can't be seen but is able to be felt as heat
radio - people can't see this energy, but radio's can turn it into sound
microwave - this energy can be used to cook food

But there are photons which have a wavelength that is just right for the human eye to see.