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Gravity on a very small scale

  1. Aug 12, 2011 #1
    Hi.. umm, I'm from the math department, and um...I'm shy.... hello physics people...

    So I saw this thing on tv, I think it was Through the Wormhole..I'm not sure..and um, don't judge me for watching "science for the uneducated masses"....

    But anyway, they were talking about gravity, and they were examining gravity on a very small scale. They were conducting an experiment that measured gravity on a very small scale and (the lab was underground to limit interference) they said things like rush hour traffic or airplanes could skew the data. I was wondering, at that small small scale, don't other forces, like cohesion and adhesion and static electricity and other properties I don't know about, don't they overwhelm the force of gravity? How do they know they are measuring gravity, and not some other force?

    Just so it's not misunderstood, we're talking about gravity BETWEEN objects, not between the earth and an object.
  2. jcsd
  3. Aug 12, 2011 #2


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    Staff: Mentor

    Yes, the electromagnetic force that causes all atoms and molecules to stick together and governs most everyday observable effects vastly outdoes gravity. They know they are measuring gravity by ensuring that the setup of the experiment screens out as many of these effects as possible. Doing experiments in a vacuum chamber would almost eliminate most effects from colliding gas molecules for example. Shielding the chamber would reduce any cosmic rays or EM radiation from affecting it and electrical effects from building up. Note that these aren't specific examples of how they perform the experiments, as I don't know the exact setups. I'm just using them as overall examples.
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