“Dropping a small object from an airplane can be lethal.”

The idea that a small object, such as a coin or a golf ball, dropped from an airplane could be lethal upon impact is a common misconception, often fueled by our intuitive understanding of gravity and the immense height involved. This myth is famously exemplified by the urban legend of a penny dropped from the Empire State Building being able to kill someone below. The sheer distance an object travels from an aircraft's cruising altitude makes it seem plausible that it would gather unstoppable (Review) momentum, leading to a fatal outcome.

However, the scientific reality of physics, specifically the concept of terminal velocity, busts this claim. As an object falls through the atmosphere, it accelerates due to gravity, but it also encounters air resistance, or drag, pushing back against its motion. The faster the object falls, the greater the air resistance. Eventually, for any falling object, the force of air resistance equals the force of gravity, at which point the object stops accelerating and falls at a constant speed known as its terminal velocity. For small, light objects like coins or golf balls, their relatively large surface area compared to their small mass means air resistance quickly limits their speed. A penny, for instance, reaches a terminal velocity of roughly 64 to 100 miles per hour, depending on its orientation. While this speed would certainly sting and could cause injury, it does not impart enough kinetic energy to be lethal.

People often believe this myth because they underestimate the significant role of air resistance and overestimate the impact potential of small mass. Our everyday experiences don't typically involve dropping objects from thousands of feet, leading to a gap in understanding how atmospheric drag fundamentally changes the outcome of a long fall. While a falling object of greater mass or with a more aerodynamic shape, like a heavy tool or a piece of ice that can accumulate on an aircraft, certainly could be dangerous, a small, light item like a coin or a golf ball simply cannot achieve the necessary speed or kinetic energy to be fatal.