A wave is one of nature's cleverest tricks: a way of carrying energy from place to place without carrying any stuff along with it. Drop a stone in a pond and the ripples race outward — but the water itself just bobs up and down. That same idea explains sound reaching your ear, light reaching your eye, and a radio signal reaching your phone.

Learn how one kind of wave works and you have a key to them all: they all travel, reflect, bend, and add together by the same rules, whether they're ripples on water, notes from a guitar, or a beam of sunlight.

Three branches to explore

Start with waves themselves — what they are, how they move, and the words (wavelength, frequency, amplitude) that describe every one of them. Then meet two famous waves up close: sound, the wave you hear, and light, the wave you see — the fastest thing in the universe.