The Long Journey of a Wave
All scenes › Chapter 4 Breaking on the beach
The end of the journey
Broken waves turn into white foam that runs up the beach, and the energy is spent here
View in 3DWhite foam, the end of the journey
A broken wave traps air, turns into white foam and rushes up the beach. Water that only turned in place out at sea now, for the first time, really flows forward. The water that rushed up then runs back down to the sea. Here, the energy the wind gave to the sea turns into sound, heat and moving sand, and the journey ends.
Why?Foam is white because countless trapped air bubbles scatter light in every direction. Water and air are both clear, but a huge number of tiny bubbles looks white.
Learn moreIn some places, water that rushed up the beach flows back out to sea all at once through a narrow channel. This is called a rip current, and it can sweep swimmers out to sea. Stay away from areas marked with warning flags at the beach.
- Distance the wave crossed (example)
- 5,000 km
calculated from the textbook equations for water waves (linear wave theory)
View this scene in 3D →Read more
Wikipedia: Breaking wave · Wikipedia: Rip current
More in the series
The numbers come from the textbook equations for water waves (linear wave theory, the dispersion relation and shoaling). In the 3D view, wave heights are drawn larger; the seabed slope and the shape of breaking waves are rough sketches.