I’ve been thinking about Einstein’s gedankenexperiment (because I’m meta like that) regarding the sealed room on Earth, and the sealed room on a steadily accelerating rocket. And the result of this thought process is… I’m confused, probably because I do not correctly understand the parameters of the experiment. My understanding was, there is supposed to be no test one can perform within the sealed room, to determine if you are “stationary” on Earth, or on a rocket constantly accelerating at 9.8 m/s. I am confused because I can think of two(ish) such tests. So I’d be much obliged if some kind person could explain why these tests would not work / or how I am misunderstanding the assertion. 1. This requires some exceptionally precise instruments, or perhaps a room with exceptionally high ceilings. In a gravity well, there are a number differences that would appear when measuring something on the floor versus the ceiling. Put a clock on both ceiling and floor, and then see if one starts to go faster than the other, weigh things at different heights, measure red/blue shifting rates at different heights. Would a rocket not have uniform g-forces within any point within the room? 2. Drop something really massive. Let’s say our subject is Wile E. Coyote, and he has an enormous anvil suspended from the roof of the room. For the sake of simplicity, we’ll say the anvil has mass equal to the rest of all other parts of the rocket combined. When the anvil is dropped, while it is falling, it is no different than if the anvil had been jettisoned, thus temporarily the mass of the rocket is effectively halved. As the force propelling the rocket would remain unchanged, acceleration would momentarily double, creating a measurable jerk (a second jerk if you’re counting Wile E. as the first). Then an opposite jerk as it hit the floor. If you were on Earth, no such doubling of weight would be felt.