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Measuring Constant of Gravitation in Basement - Experiment

  1. 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.

    http://www.fourmilab.ch/gravitation/foobar/

    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.
     
  2. jcsd
  3. 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.
     
  4. Thank you TurtleMeister, I'm sure I'll learn more about these later on, but thanks for clearing any doubts.
     
  5. mgb_phys

    mgb_phys 8,952
    Science Advisor
    Homework Helper

    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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