Go and catch a falling . . .
Physics are everywhere, and so are birds
The 12th grade Physics class had a lot of people in it who needed it for college but would forget it when they went out the door. But I’m betting most of them remember the “hands-on” experiment proving that everything falls at the same rate.
When Walter Givens said to move all the desks out of the way, the reaction was, as one might expect, gender-specific. The girls wondered why those perfectly straight lines were being defiled, and the boys said, “Yippee! Chaos!”
In one corner of the classroom Givens set up an electromagnet with an empty number 10 can hanging from it, with the open end facing the other corner; and in that corner was a piece of half-inch pipe with two wires running to the can. One wire was wrapped around the pipe and the other was bent into a hook that let it hang on the open end of the pipe.
A ball bearing went into the pipe, and the experimenter blew into the pipe, aimed dead center at the hanging can. The ball bearing came out one end, knocked the hook of wire loose, broke the circuit to the electromagnet, and the can fell. But the ball bearing still hit the can dead center, because they were falling at the same rate and began falling at the same time.
Yeah, we were sore amazed, and it stuck in my head. It wasn’t really hands-on, but lips-on, with the teacher assuring us that we wouldn’t catch any diseases off two square millimeters of pipe that we wouldn’t catch at the drive-in anyway, although I doubt he phrased it that way.
The flip side of that Newtonian principle is that if two things are moving at the same speed forward, they’ll continue to move at that same speed even if one is falling. I remember attempting to demonstrate that as a younger man by jumping out of the back of a moving pickup to make the point that if I hit the ground running, there was no danger. There was alcohol involved, and I hit the ground running the wrong way, but the truck wasn’t moving very fast, so it was more lesson than disaster.
The principle came into play this morning when the bird shit hit my sleeve even though I was under the patio umbrella. Because the bird made his move, so to speak, well out from the umbrella but his payload continued to travel forward at the same speed he was, and it came in at an angle and with an accuracy the Norden bombsight could only dream of.
The shirt and I have a history. Sage-green linen, a color Deb likes on me and a material I like when it’s ten years old and threadbare as a rusted fence. My child wore it for a while after getting a tattoo during his last visit. (They’re cheaper here than where he lives.) He had to put some sort of gunk on the fresh tattoo and didn’t want to mess up one of his shirts, but my solace is that he didn’t look as good in that color as I do.
I’m a border-line hoarder. As with many of my idiosyncrasies it stops just short of the need for medication. I have my gym shirt from junior high school, but I also have a number of 12-cent comic books from that era that will sell for $100 or more. Knowledge of that hoarding instinct made Deb pause and ask if I was sure as she held shirt over the open trash can. But the pocket was torn, the collar was ragged, and you could drop it over a dime and tell if the coin was heads or tails.
Besides that, it had unwittingly helped me prove a principle of physics I learned half a century ago, so I didn’t really need it anymore.