Elevator Physics: When Do You Feel Your Heaviest?

You experience changes in your perceived weight within an elevator due to acceleration. When an elevator begins to move upward, you feel heavier. Conversely, when it slows down at the end of a downward trip, you also feel heavier.

Physics defines 'weight' in multiple ways: mass, gravitational force, and the upward force exerted by a scale. Your mass and Earth's gravity remain constant. However, the upward push from the scale, which we perceive as weight, changes with the elevator's motion.

Astronauts on the International Space Station, despite being under Earth's strong gravity, feel weightless because they are in continuous free fall. They don't feel the upward push of a surface.

When an elevator accelerates upward, the floor must push back harder than gravity to move you. This increased upward force makes you feel heavier. When the elevator slows down at the top of a journey, it must accelerate downward slightly to decelerate you. This reduces the upward force, making you feel lighter.

This phenomenon is related to Einstein's equivalence principle, a cornerstone of general relativity, which posits that gravity and acceleration are indistinguishable locally.