Exploring the wonderful world of Physics

Today at lunch, my brother Anthony wondered aloud whether PNC Park allows one to bring a whole apple into the game, or only a cut-up apple.

"What difference would it make?" I asked.

"You can throw whole fruit farther," he said. "It weighs more."

"The weight shouldn’t make any difference. A slice of apple has roughly the same mass per volume as a whole apple. They should travel the same distance. "

"I’m telling you that I can throw a baseball way farther than I can throw this slice or apple, and a baseball is like a whole apple."

"Maybe the shape would affect it. The spin reducing the friction from the air," I said.

"I think it has more to do with the relationship between the size of my hand and the size of the apple slice," he said.

"There is no way that has anything to do with it."

So we conducted a short experiment. I didn’t want to waste a perfectly good apple, so we used a de-zested, dried out orange that I was planning to throw out anyway. It was close to the weight and shape of the apple. We went to the alley that runs along my house, and Anthony threw first the apple slice and then the orange.

Result: The apple slice traveled about 60% of the distance the dried-out orange traveled. This was less of a difference in distance than Anthony had expected, and more than I had expected. I still believe the shape of the objects played a big role. The round orange had less surface area for its mass, while the apple slice with its flat size had much more surface and would have met more resistance from the air.

Of course, our experimental design was completely crap, as the trial was riddled with errors. The alley slopes upward steeply, so Anthony had to throw uphill, which means the arcs of the projectiles were cut short on the far end. The orange would have landed several feet farther on if the surface had been flat. And there’s no way to know if the force of Anthony’s throws was consistent; had we been more scientific we’d have used a device for throwing or run more trials and averaged the results. To remove shape from the test we should have trimmed the apple slice into a round shape. But then we’d also need to make sure both objects had the same surfaces; a peeled apple and a small, round piece of apple would have been the best test objects. And of course we didn’t control for the effects of wind either.

But still, we were satisfied that we had explored the question and achieved an interesting result.

When we returned to the office, Anthony took another approach to answering the question. As it turns out, fans are permitted to bring both whole fruit and sliced fruit to the ballpark, as long as the total food brought fits into a 16"x16"x8" soft-sided bag.