It’s a tale as old as tall buildings themselves, passed down from one generation to another: If you drop a penny off a skyscraper, it could kill a person standing below. But is there any scientific validity behind this claim? Let’s dissect the myth and rely on the empirical evidence to find its origins and determine its veracity.
The Origin of the Myth:
It’s difficult to pinpoint the exact origin of the penny-dropping legend, but tall structures have always held a certain allure. As skyscrapers began to rise in the late 19th and early 20th centuries, they were met with a mix of awe and fear. Just as urban legends and myths naturally spread in new environments, the penny tale seems to have found its footing in this era, bolstered perhaps by the awe and anxiety surrounding these towering giants.
The Science Behind the Myth:
1. Terminal Velocity:
Every object in freefall, under the influence of gravity alone and ignoring any other forces, will eventually reach a constant speed called its “terminal velocity.” This happens when the downward force of gravity is equal to the upward force of air resistance. At this point, the object won’t accelerate anymore and will fall at a constant speed.
For a penny, this terminal velocity is around 30-50 mph (48-80 km/h) due to its flat and wide shape which makes it subject to more air resistance. This is much slower than many might expect and is far from the speeds required to make a penny deadly.
2. Mass and Impact:
A penny’s weight is negligible, weighing in at only 2.5 grams. For it to be lethal, it would need both mass and a high velocity, which, as we’ve seen, it can’t achieve merely by being dropped from a height.
3. Real-World Experiments:
Various real-world experiments and demonstrations, including those by TV shows like “MythBusters,” have illustrated that a penny dropped from a height like the Empire State Building would hurt slightly if it hit you but would certainly not penetrate the skull or cause fatal injuries. On the “MythBusters” episode in question, the penny reached its terminal velocity and was found to have insufficient energy to cause any serious harm.
Comparisons:
To further debunk this myth, consider another similar-sized but more aerodynamic object: an arrow. Arrows can be deadly, but they achieve their lethality through a combination of factors: being pointed, having kinetic energy, and being launched at high speeds (often over 200 mph or 322 km/h) from a bow. A penny, with its flat shape and maximum speed of 50 mph, is nowhere near this realm of danger.
Conclusion:
The idea that a penny dropped from a skyscraper could kill a person is just that – an idea, a myth. Scientific evidence clearly shows that while it might be unpleasant to have a penny fall on you from such a height, it’s nowhere near lethal. Myths like these are captivating, reminding us of the power and mystery that tall structures can evoke. However, when it comes to the deadly penny drop, science firmly grounds the legend.
Sources:
- MythBusters. (2003). “Penny Drop.” Discovery Channel.
- Jones, D. E. H. (1982). “Falling Pennies.” New Scientist, 94(1302), p. 464.
- Drag Force & Terminal Velocity. (n.d.). Retrieved from Physics Classroom: http://www.physicsclassroom.com/class/newtlaws/Lesson-3/Drag-Force-and-Terminal-Velocity