The Penny Dropped From A Skyscraper: Testing MythBusters' Experiment

Have you ever wondered what would happen if you dropped a penny from the top of the Empire State Building? Could it actually be deadly? Could it reach a speed fast enough to cause serious harm to someone walking on the sidewalk below? These questions have captured the imagination of many, and the MythBusters team once explored this intriguing concept. Join us as we revisit their experiment and delve into the physics behind falling objects and their potential dangers.

The MythBusters episode that tackled the "penny from a skyscraper" myth featured original MythBuster Adam Savage and science communicator Derek Muller. The goal was to test whether a penny dropped from the Empire State Building's height of 443 meters could be lethal to someone on the ground. As they embarked on this experiment, they were well aware of the common belief that such an event could potentially result in harm due to the penny's accelerated speed during free fall.

Dropping a penny from a great height seems like a straightforward scenario, but understanding the factors that come into play requires a closer look at physics. To provide context, a penny weighs around two and a half grams, making it relatively light. In terms of mass, a penny is about half to a quarter the weight of a bullet. Ignoring air resistance, a penny dropped from the Empire State Building would accelerate to over 300 kilometers per hour by the time it hits the ground, which is approximately half the speed of a typical bullet.

The MythBusters team had previously experimented with shooting pennies at each other using contraptions. These contraptions allowed them to test the impact of pennies traveling at high speeds. However, the ultimate test was yet to be conducted: dropping pennies from the height of the Empire State Building onto a target below.

In preparation for the experiment, Savage was taken up in a helicopter with the intention of dropping pennies on Muller, who stood on the ground below. The helicopter's downdraft created additional air currents that impacted the trajectory of the falling pennies. Muller, while apprehensive, stood ready for the experiment as pennies rained down from the sky. The anticipation of the impact was evident as he braced himself for the incoming pennies.

As the experiment unfolded, it became clear that the falling pennies did not pose a significant threat. The impact of the pennies hitting Muller's body caused some discomfort but did not result in any serious harm. Muller's reactions, captured on camera, revealed his tense anticipation and the experience of being hit by the pennies.

So, why did the experiment result in minimal harm to Muller? The answer lies in the concept of terminal velocity. Terminal velocity is the maximum speed an object reaches during free fall when the force of gravity pulling it downward is balanced by the force of air resistance pushing against it. Different objects have different terminal velocities based on their mass, shape, and size.

For objects with similar sizes and shapes, their terminal velocities will be comparable. In the wind tunnel, Muller demonstrated how objects like raindrops fall at their terminal velocity due to air resistance. Raindrops have a low terminal velocity of about 25 kilometers per hour, and they pose minimal danger when falling from the sky.

However, the MythBusters team did not stop at pennies. They also explored the potential danger posed by ballpoint pens dropped from a skyscraper. Despite their increased weight compared to pennies, plastic ballpoint pens still did not reach speeds high enough to be lethal upon impact.

The experiment highlighted the complex interplay between weight, shape, size, and air resistance in determining the potential danger posed by falling objects. While some projectiles, like hailstones, can reach high terminal velocities and pose risks, many everyday objects do not possess the combination of factors necessary to become lethal during free fall.

In conclusion, the myth that a penny dropped from a skyscraper could be lethal was effectively debunked by the MythBusters experiment. While the idea captured people's imaginations, the physics of terminal velocity and air resistance play a crucial role in determining the potential harm of falling objects. The experiment showcased the importance of understanding the scientific principles that govern everyday phenomena and the power of experimentation in dispelling myths and misconceptions.