How a Simple Tank Tilt Reveals the Physics Behind Clouds and Ocean Waves

3-Second Blueprint (English)

1. Tilting a tank ~8 degrees makes dense salt water flow downhill beneath lighter fresh water flowing uphill, creating shear.
2. Velocity shear across the density boundary destabilizes the interface, amplifying tiny disturbances into curling billows.
3. These rolling Kelvin-Helmholtz vortices rapidly overturn and break down into turbulent mixing between the two fluid layers.