Weightlessness on Earth?
Part of the Einstein exhibition.
Timed-entry ticket reservations continue to be required for Museum entry. Facial coverings are strongly recommended. See Health and Safety.
Part of the Einstein exhibition.
One day, while Einstein was daydreaming at work, he imagined that a housepainter would experience weightlessness if he fell off a roof.
"If a person falls freely, he won't feel his own weight. This simple thought made a deep impression on me." - Albert Einstein
This activity is a physical demonstration of Einstein's idea known as the "equivalence principle." This means that in a freely falling reference frame (that of the falling cup or person), gravitational effects will not be observed. Students will watch a demonstration of a falling cup of water with a hole in it. They will see that as the cup falls, the water stops running out of it.
One on level, this is a simple demonstration of the concept of weightlessness in a freely falling reference frame. On another level, it illustrates the concept behind Einstein's Equivalence Principle, which states that, locally, gravity is equivalent to being in a accelerated reference frame; or, gravity and acceleration by an outside force produce the same effect on a local object (in this case, the cup).
Copyright © 2002 American Museum of Natural History. All rights reserved.