Being from New York I have definitely seen my fair share of skyscrapers and always found them fascinating. I’ve stared up at these miraculous buildings countless times. One day, when I was younger, my grandma decided to take my brother and I to the top of the Empire State Building. I vividly remember finally reaching the top and, rather than being amazed by the view, my grandma lectured my brother and I to not throw any coins over the railing. “If you drop a coin it could go right through someone down below and kill them!” I was petrified.
It’s now some years later and I find myself having trouble believing my grandma’s prediction. But let’s say she’s right for the moment. Obviously this concept would not just apply to the Empire State Building. A skyscraper is classified as a building with more than 40 floors and taller than 492ft. If you drop a coin from the top of a skyscraper and it happens to hit someone walking below, the assumption is that you could kill them. And there are many people who tend to believe this concept. Now, as crazy as this sounds, is it possible? Is this theory actually true or have scientific experiments been conducted to prove this statement false?
Null Hypothesis: If a coin is dropped from a skyscraper and hits someone they will not die.
Alternative Hypothesis: If a coin is dropped from a skyscraper and hits someone they will die.
Scientific American states that “it’s extremely difficult to turn a penny into a lethal weapon, and hurling it over the barricades at the top of the Empire State Building won’t get the job done. Even from that height, a penny is too small and flat, and cushioned by too much air, to become a torpedo.” Rather than the penny falling faster and faster towards someone’s head it begins to fall lighter. If this penny were aimed at you, instead of feeling as though you were hit in the head by something harder than a brick (as some assume would happen), it would simply feel as if you’ve been poked in the forehead. But these are merely statements. Not experiments. Even though this concept of a penny killing you still seems highly illogical many people, including tourists of the Empire State Building according to John Stossel, demonstrated concern based around this theory. As we know, absence of evidence is not evidence of absence. So where is the scientific evidence?
A scientific experiment was performed by Louis Bloomfield to test this death by coin theory. Bloomfield recreated this myth by filling a large weather balloon with helium and then attached a penny dispenser from it which dispenses one penny at a time. He then released the balloon hundreds of feet into the hair and ran around with a remote control, which controlled when pennies were dispensed, trying to catch the falling coins. Bloomfield was not successful and didn’t catch one penny. But, as a result, he was hit by a few of the falling pennies. As crazy as this experiment sounds the results were actually beneficial in evaluating the null hypothesis. Bloomfield’s findings directly correlate to basic physics and the concept of terminal velocity. Terminal velocity is defined as “the highest velocity attainable by an object as it falls through air.” It is also determined by the object’s weight and air resistance. Bloomfield states that the pennies, “reach terminal velocity and no matter how high we put the balloon, they never picked up any more speed. Because a penny is lightweight and not aerodynamic, air resistance slows it down so much that its terminal velocity is quite slow.”
This article, by Daven Hiskey, also contemplates the death by coin myth and proves how this theory is entirely false in step by step form:
1.) No air-resistance: “If there were no air resistance on the penny as it fell, that would mean it would reach a maximum velocity of around 190-ish miles per hour when it hit the ground, taking just shy of 9 second to do so.” This might sound really fast but even this speed is not even high enough to penetrate a person’s skin, let alone kill them.
2.) Weight of the penny: A penny has roughly the same mass as a .22 caliber bullet. If a bullet were shot at a speed of 600 miles per hour it would penetrate your skin because “the surface area that strikes your skin is much smaller”. But a penny, even shot at that speed, would not have the capability of breaking through a person’s skin. This was even proven by Myth Busters. “They shot a penny at over 700 mph at a gel “skull”. The penny wasn’t even able to penetrate the gel at all at that speed, which was over three times the speed a penny would reach falling from the top of the Empire State Building with no air resistance.”
3.) Real life: “In open air, with no real updraft or breeze, a penny’s terminal velocity is going to be around 30-50 miles per hour. If there is a good wind, even without an updraft, that’s going to drop significantly.” This means that if a penny were to be dropped from the top of the Empire State Building it would have an even lower terminal velocity due to the weather conditions.
These clear and well-executed experiments makes it extremely apparent that a penny dropped from the top of a skyscraper does not have the capability of killing anyone below. The weight, air-resistance, and aerodynamics all back up this conclusion. For these reasons the alternative hypothesis can be rejected and the null hypothesis can be accepted. Coin by death is simply a myth. There is no truth to it.
Take Home Message: Just because a penny is “safe” to throw from the top of a skyscraper does not mean that all small objects are just as safe. Hiskey states, “It really has a lot to do with surface area to weight ratio and how aerodynamic the thing is.” He gives the example of a ball point pen. This object is very light, similar to a penny, but much more “lethal” to those below. This is an interesting aspect to consider. Could items found in the average woman’s purse or average man’s pocket kill someone below even if dropped by accident? “Don’t dump your handbag out the top of a building. Something in that bag is likely to go awfully fast.” (Bloomfield)
I was really excited when I read this title. I used to be so fascinated with the idea of a simple coin killing someone. I watched this episode on Mythbuster’s a while ago, and the question was quickly answered. I think you might have mixed up your null and alternative hypothesis. A null hypothesis is a statement of “no difference, or no effect” So, I believe that the statement of “no effect” would be not dying from the coin. Either way, I really enjoyed this blog. It really make sense that the surface area effects how fast an object will fall. It is also very good to know that other small objects may be deadly if they are dropped from the top due to different surface areas and weights. In both circumstances the weather could affect how fast the object falls. So maybe the weather decreases the chance that it will hit anyone at all. I think that no matter what you drop, there is a very slim chance that the object will kill someone. There are so many other third variable that affect this, such as the person’s location on the street, where the object hits them, etc. Thank you for sharing one of my favorite topics 🙂
I have heard that myth since I was a little girl so I am glad to see that it is most likely not true! When I was in middle school, I thought that this myth had to be true as I was learning about velocity. As the penny goes farther down, it would continue to speed and speed up until it got to a deadly speed, right? Apparentlythis is not so . The penny is tiny so it would receive a ton of air resistance, and when it reaches a specific velocity, the “drag force” equals the gravitational pull and the penny will continue to fall at a constant speed instead of getting faster. With this occurring, there is no way it can get to be fast enough to penetrate a skull. You even mentioned that Mythbuster’s did a test and the penny could not penetrate the skull at speeds way faster than a penny could ever go if falling from the empire state building. But I never expected as a middle schooler for the penny to go into someones head, but to hit them in the most unfortunate spot- the temple. Did Mythbuster’s test that? That is a test they may want to think about doing.
I too have heard this old tale. It is very funny because I even remember watching videos about this in middle school and high school. You did a great job in the construction of your blog. It would be interesting to find out what you could throw of the top of a skyscraper to be able to kill someone. How much weight would it take? What would the object have to look like? Would there have to be a certain projection? I believe that there would be many third variables in constructing an experiment like that. Overall, great job I really enjoyed reading your blog. Here’s the myth busters video where they do the penny experiment: https://www.youtube.com/watch?v=PHxvMLoKRWg