Could A Penny Falling From A Skyscraper Really Kill You?
A physicist finally answered this age-old question.
Have you heard the theory that a penny dropped from the top of a skyscraper could kill a person if it hits them?
Adults and children alike love to toss around this tale. But is it plausible that something as small as a penny could cause lethal damage to the human body? It sounds crazy, but maybe just crazy enough to be true. After all, the Empire State Building’s observation deck rises 102 stories over the sidewalk. That’s a long way for a penny to fall—and plenty of distance to pick up momentum on the way down.
Experts decided to put the theory to the test to see if pedestrians walking underneath those tall buildings are truly at risk of unexpected death by the tiny copper-like currency.
Taking A Hit For Science
Would you put your life on the line to prove a point? That’s exactly what physicist Louis Bloomfield did to determine if a penny thrown from a skyscraper could actually kill someone. Since throwing objects from the top of somewhere like the Empire State Building is frowned upon, Bloomfield set up an experiment to replicate the conditions of that scenario.
Bloomfield released a helium ballon carrying pennies into the sky. Once it reached a height of a few hundred feet, he used a radio-controlled remote to release the pennies into the air. Then, he attempted to catch them with his bare hands.
And, what was the outcome? Bloomfield not only survived, but found the task amusing.
“The pennies didn’t hurt,” he told 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.”
Based on his calculations, Bloomfield figured out the pennies fell to the ground at about 25 mph—not enough speed to strike a lethal blow.
Was Bloomfield simply lucky? Not at all. There’s a simple scientific explanation.
Science Saves The Day
Two factors prevent a penny from falling fast enough to kill someone.
First, the penny’s shape is not aerodynamic. This means its design does not cut through the air efficiently, making it move more slowly through the air than something with a sleeker design.
Second, there is a concept known as terminal velocity. It sounds like a complicated term, but it’s a simple concept. Falling objects can never accelerate beyond the force of gravity (thank you, Sir Isaac Newton!) Eventually, the drag of the air force becomes equal and opposite to the downward pull of gravity. This means the penny cannot fall any faster; it has reached terminal velocity. Bloomfield found that pennies reach their terminal velocity (about 208 mph) after only about 50 feet. Once it reaches that point, the penny slows to about 25 mph.
A Penny Can Hurt, Though
What would happen if someone was hit by a penny traveling at its terminal velocity, though? Back in 2011, co-hosts of the popular Discovery Channel show “Mythbusters” focused on this precise question. Host Adam Savage was able to build a device that would shoot a penny at its terminal velocity. He volunteered to be hit by the penny traveling at just over 200 mph. Check out the results in the video below.
The moral of this story? A penny falling from a skyscraper may not kill you, but it will sting.