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Measuring Constant of Gravitation in Basement - Experiment

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Apr5-09, 07:52 PM
P: 28
The other day I was reading a simple experiment to determine (yes, very roughly) the constant of gravitation, all using simple tools in your basement.

What struck me about this experiment is another that I remember from childhood cartoon shows - using a free-swinging pendulum which will 'rotate' due to earth's rotation over the course of a day. I suddenly got the notion in my head that this gravitation experiment, where the two masses are hung by a string, might be affected by natural rotation! Someone please either confirm this potential error, or help me get this doubt out of my head.

PS: I'm assuming the damping 'stuff' is the solution to my question, if anyone can fill in the blanks it would be greatly appreciated.
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Apr5-09, 10:03 PM
TurtleMeister's Avatar
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The experiment in the link you provided is a torsion balance. It is not influenced by the Earths gravitational field or rotation in the same way that a pendulum is. It's motion is almost entirely determined by the masses used in the experiment.
Apr6-09, 07:37 AM
P: 28
Thank you TurtleMeister, I'm sure I'll learn more about these later on, but thanks for clearing any doubts.

Apr6-09, 09:20 AM
Sci Advisor
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Measuring Constant of Gravitation in Basement - Experiment

It's not impossible, we use to do it as an ugrad practical lab. the only 'special' equipement we used was an internal room in a basement (an old darkroom) that was well insulated from vibration and temperature changes.
We used a telescope viewing through a window in the wall rather than a camera.

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