“Dropping a penny from a skyscraper can kill someone.”

The notion that a penny dropped from a skyscraper could become a deadly projectile is a pervasive urban legend, often associated with iconic tall structures like the Empire State Building. This myth has been passed down through generations, captivating imaginations with the dramatic image of a small coin transforming into a lethal weapon due to extreme height and gravity. The scenario is so frequently recounted that it has cemented its status as a classic misconception, likely stemming from a natural human intuition about falling objects and the immense scale of skyscrapers.

However, the laws of physics tell a different story. While gravity would indeed accelerate a falling penny, it would not do so indefinitely. A crucial factor often overlooked is air resistance. As the penny gains speed, the drag force from the air pushing against its flat, lightweight surface increases significantly. Eventually, the force of air resistance would balance the force of gravity, causing the penny to reach its "terminal velocity" – a maximum, constant speed it cannot exceed, regardless of further height. For a penny, this terminal velocity is relatively slow, typically around 25 miles per hour, and it would achieve this speed after falling only about 50 feet. At this speed, a penny would deliver a noticeable sting upon impact but is far from capable of piercing skin or causing a fatal injury.

The persistence of this myth largely stems from a misunderstanding of how air resistance affects falling objects, particularly those with low mass and a broad surface area. People intuitively believe that objects continuously accelerate the entire way down from a great height, leading to a dangerous velocity. Furthermore, the myth contains a "grain of truth" in that some heavier or more aerodynamic objects, if dropped from extreme heights, could indeed be dangerous. This correct understanding about other falling objects sometimes incorrectly extends to lighter items like a penny, fueling the dramatic appeal and widespread belief in this captivating but busted myth.