Weightlessness on Earth?
Part of the Einstein exhibition.
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).
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