Very watchable demonstration of "Pendulum Wave Behavior."

Years ago I saw a giant version of this demonstration in the lobby of a physics laboratory at Cal Tech. The spheres were a foot in diameter! …. impressive, but sadly all just stainless steel. This video nicely captures this method of visualizing “Pendulum Wave Behavior” and is much more colorful. It is amazing what patterns of motion evolve over time.

First, I soldered an old lamp cord to the flash bulb and poked it out the window. A ladder got me high enough to place the bulb in the gutter about where the wood pecker was signaling for a mate. I attached one wire in the cord to a battery and taped the other wire to the side of the battery where I could easily grab it in the dim light of dawn.

It rained for two days and I had to get the ladder out and make sure my quite buoyant flash bulb had not been flushed into the downspout.

Dawn of the third day, we were once again awakened by the repetitive din of pecking. I tiptoed to my battery and holding the loose wire, awaited the next round of banging. When it came, I touched the wire to the other terminal. I didn’t see a flash, these bulbs make no noise, but the pecking stopped immediately and we were not bothered ever again.

True story, Paw, Dad, Robbie

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