What Causes the ‘Waves’ on a Beach and How Are They Measured?

Waves happen because the wind pushes water. Imagine you're in a puddle, and someone blows on it, ripples spread out from where the wind touched the water. On a beach, big waves come when the wind blows strongly over the sea for a long time. Scientists use special tools, like rulers or even sensors that float on the water, to see how high and far apart waves go.