Light- the natural agent that stimulates sight and makes things visible.
This is a diagram of a triangular prism dispersing a beam of white light. The longer wavelengths and the shorter wavelengths get separated.
A source of light makes light. The Sun and other stars, fires, torches and lamps all make their own light. Some animals, like fireflies and glow-worms, are light sources, They make their own light.Smooth surfaces such as mirrors and polished metals reflect light well. Dull and dark surfaces such as dark fabrics do not reflect light well.
‘Cat’s eyes’ on the road reflect light from car headlamps to help the driver see the road at night.