"Roger Long" wrote in
:

Build a tripod on an inner tube or life ring type float and hang a
pendulum in it. As a wave goes by, the pendulum will always point to
the center of the float, even if the ring goes upside down inside the
tube of a breaking wave. There are videos of this in a wave tank.
The pendulum can point straight up. It's the same kind of motion that
lets you sweep a glass of water upside down without spilling.



Hmm...I got a campfire kettle tripod and inner tube. This sounds like a
great spring project to set afloat and test this spring, especially for the
kids to watch and wonder.

Thanks, Roger!