If a penny drops from a skyscraper, could it kill you?
No one gets out of this world alive, but could a penny that drops from a skyscraper be what kills you? Long before people spent way too much obsessing about a zombie apocalypse, kids and nerdy scientist types would theorize about random happenings that could put the unsuspecting in an early grave. This “penny from a skyscraper” theory isn’t quite as old as America’s first one-cent coin since that was invented in 1792. But it probably wasn’t that long after the first skyscraper made its appearance in Chicago in 1884-1885 that people started realizing that objects dropped from the top could become lethal weapons.
But just how small of an object could do the fatal trick? A penny? And how high would the building need to be? Apartment building in your neighborhood height, or Empire State Building? That’s what modern day science sleuths have set to figuring out. But don’t worry. Science does have an answer to the age-old question of “Could a penny dropped from a skyscraper kill you?”
Faster than a speeding bullet?
Before the debunking occurs, here are the basics of this myth. The idea is that even a light penny would gain momentum as it fell from stupendous heights. It would be going so fast by the time it reached the sidewalk, it would essentially tear a hole in the hapless human just trying to visit the New York or Chicago landmark because it’s a touristy thing to do. Sounds reasonable, right?
In reality, though, pennies fall from great heights are less like speeding bullets and more like floating leaves. What’s up with that? The penny’s flat shape creates some of its floating characteristics, according to no less an expert than the United States Mint. And then there’s this concept of terminal velocity. That means gravity from a fall does make a penny begin to fall quickly, but only to a point. The faster it goes, the more air resistance it meets. After it falls about 50 feet, the forces of gravity and drag find a balance and the penny would slow to about 25 mph until it hits the ground (or that unsuspecting tourist.) That speed with such a small, light object is not deadly.
The professor who escaped death by penny
University of Virginia physics professor Louis Bloomfield tested that claim in person about 12 years ago. He used himself as the test subject. (We suspect as a physicist he knew he’d be okay.) Bloomfield rigged a helium balloon and had it drop Lincoln cents on him from hundreds of feet above. Not only did the coins not injure the not-so-mad scientist, but he could also barely catch them when he tried. “The pennies didn’t hurt,” he said in USA Today. “They bounced off me and it felt like getting hit by bugs, big raindrops, or little hail pellets. No bruises, no injuries. I was laughing the whole time.”
Without air, you could kill someone with a penny
But don’t look down on people who have believed this penny myth all this time. Because it turns out that pennies or even small beads could indeed slay an enemy when dropped from dizzying heights. The only reason they don’t do so on planet Earth is that we have air. It pushes aerodynamically unstable items up, which halts the acceleration. You know how skydivers sort of get a little wind beneath their wings instead of crashing to earth? The effect is the same on a penny: the air puts a stop to that dangerous acceleration rate.
In an airless environment, you really would have to look up constantly when treading ground below a skyscraper. (If this particular society did not have air as we know it, but did have a form of exchange that could be tossed from high dwellings.) Bloomfield estimated that without air, a penny or even a piece of paper would reach 210 mph between the top of a skyscraper and the sidewalk below. At that speed, you don’t need much mass to do damage. So maybe the new question is, could a paper cut kill you?