What is light

Someone ask: What is light

Caveman say light is thing that lets tribe see world. It is both wave and tiny particle-like packet, like firelight splashing from many sparks at once. Sun, fire, and lamp send light as electromagnetic energy, meaning no air needed to travel. Light race very fast through space, then hit eye or rock or leaf. Some light bounce, some soak in, some pass through, and that is why colors and shadows happen. Red light and blue light are different parts of same river, just with different wave shape. Caveman see only small slice of huge light river. Cave wisdom: light is how universe throws messages to eyes.