A sea like a mirror

A day with no wind

On a day with no wind at all, the sea is as smooth as a mirror. Left alone, water settles flat. For waves to form, something has to shake the water. Out at sea, the thing that does this most is the wind.

Why?Earthquakes, passing ships and the pull of the Moon also make the water move. But the waves you see at the beach every day are almost all made by the wind.

Learn moreTsunamis and the tides are ocean waves too, but they form in a completely different way and are a different size. This story follows only waves made by the wind. Each corner of the grid on screen is 'one bit of water', placed where the textbook wave equations say it should be.

Wave height

0 m

calculated from the textbook equations for water waves (linear wave theory)