Lake Michigan as a Giant Wave Tank

When I studied physics in high school many eons ago, we used wave tanks with water to examine waves. A few days ago, flying home, I looked down at Lake Michigan, on what was apparently a very calm day down there. The “crib” building (water intake portal a mile or so out into the lake from shore) was pulsing out circular waves, just like a pebble tossed into the lake. Similarly, emanating from the shore, were pulsing waves shaped just like the geometry of the shore. It was like the crib, and the shore,were vibrating, and sending out small waves, just like the wave tanks from my physics tanks of old. What would cause this?

The crib probably was vibrating. It’s mostly just floating, and like anything floating, can bob up and down.

The shore, of course, was not. I imagine that what you were seeing was waves reflected off of the shore, not originating at it.

Water intake cribs don’t float.