Dartmouth professor discusses Foucault's pendulum

Physics and astronomy professor Jim LaBelle discusses the science behind a classic physics experiment, Foucault's pendulum, while seated next to Dartmouth's pendulum in Fairchild Tower.

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[bigboam]

One of the best explanations of this experiment I've ever heard. Thanks and aloha!

[Jem'appelle lanoosh]

He looks like dr.house

[TheJiminiflix]

SO it does not PROVE the earth is rotating? I wonder how, if the earth is rotating at 1000 km and hour or so, why if I fly an hour in a plane opposite to the rotation of the earth do I not end up in roughly the same place? Or if I send a balloon high into the stratosphere for many hours that it comes back down only a kilometer away from me.

[Squiglypig]

Speaking of gravity, gravity proves that we're moving around the sun. Why? Because the sun is the most massive object in the solar system, causing it the be the object that the rest of the solar system is trapped by.

So no, it's not the only evidence. Hell, the coriolis effect is literally the effect that the earth's rotation has on objects in the air, like bullets, planes etc.

[Squiglypig]

But that explanations is completely debunked if we even START to consider that gravity has any say in celestial mechanics.

[lastmiles]

Please look up axial precession. The pole star changes on a cycle of about 26,000 years. 14,000 years ago the pole star was near Vega back then. Also, strictly speaking, if you take a time lapse photo of the pole star today you will see it trace a small circle, very small. You need a telescope for this. Polaris is a trinary star system as there are three stars there, close to 0 RA and 0 Dec. Close .. very close. Please search for Polaris as seen by the Hubble Space Telescope.

[lastmiles]

from 0:38 to 2:09 I counted 10 swings. So that is 91 secs for ten swings. So guess 9.1 seconds per cycle. If the length of the pendulum is based on T = ( 2 * pi ) * sqrt( L/g ) with g at 9.81 m/s^2 then my guess is the pendulum is about 20.6 meters long.

[Kat Rockenbach]

Thank you!

[Abidur Rahman]

Yes, when the electricity goes off. The pendulum uses an electronic mechanism to keep it going; otherwise it would lose its energy due to friction and stop after a few hours.When you stand near the pendulum, you hear clicks with each swing. This sound is produced by relays controlled by an electric eye – two pairs of lights and sensors that recognize when the beam of light is interrupted by the passing of the cable – that turn a magnet on and off to give a little pull.

[Kat Rockenbach]

Can someone tell me how does the pendulum doesn't stop its movement eventually?