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From: physicsanimations
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  • Is there any relation between the rotation of the stars and the rotation of the pendulum? Stars rotate CCW around the celestial north pole; the pendulum rotates CW. Stars rotate CW around the celestial south pole; the pendulum rotates CCW. Both stars and the pendulum do not rotate at the equator.

    jtb

  • @Noshoesworn By the way, with your exigences you are not certain if Earth rotates, until an independent observer reproduces the experiment.

  • @Noshoesworn . Revision by specialists can confirm ou impugnate such elements in a given test, what leads to the conclusion that peer-reviewing is a way to discuss a experiment, but it does not “adds” science to it.

  • @Noshoesworn Peer-reviewing is only a rule to publish experiments in scientific publications, not a rule of the science speech. It has nothing to do with the internal logic of the experiment itself, neither with the logic nexus with factual premises, demonstration process, verification criteria and results. All these must be found in the structure of the proposed experiment.

  • @Noshoesworn thats because not everybody can use a steel wire 220 feet long, suspend a 62-pound iron ball and calculate the exact flux of magnetic induction necessary to counter the friction... and THEN, build a foulcault's pendulum... you moron

  • to explain the motion one needs to take into account the coriolis force!

  • @PawelKolasa That's incorrect. The electromagnets only help to maintain its constant motion. It's like having an unlimited supply of fuel in your gas tank; it doesn't affect the direction of the car, only the distance it travels. The pendulum falls victim to friction due to air resistance, so the electromagnet counters those forces so that the experiment can continue and the main focus of the project can be observed. In a frictionless environment, it would never stop swinging.

  • @PawelKolasa

    The magnets aren't there to make it move, it's there just to make sure that pendule continues moving despite the interaction with air, and the movement of a pendule is independent from the earth, so what is beneath that pendul is connected to earth and is affected by its rotation, that's how we prove earth turns.

    And what you said is just stupid, you treated something that has been in place for years by great scientist as fake?! You are fake!

  • i know how the pendulum work but i still find it so hard to visualize the spin of the earth causing that movement

  • and...???

  • earth routes on its axis

  • Did you work that out on your own or are you trying to get the award for most obvious moron on the axis rotating planet? Guess what people... water is wet and wood comes from trees! X|

  • Well, the point where the pendulum is mounted to the ceiling is also rotating with the Earth, so how can it prove the rotation of the planet? The Earth should spin around that mounting point of the pendulum to prove anything ie. the ceiling should be motionless and everything should spin around it :D

  • Maybe because the swinging pendulum isn't affected by that rotation to the same degree as it's mounting.

    You can test it in rudimentary way, I guess. Like. glue a coin to a string and hang it from something. Then flick it to get it in motion and turn whatever you're hanging it from. The swinging penny won't "rotate" like the object it's hanging from.

    It's not the same type of design as a clock pendulum as far as I know.

    Alas, I could be wrong and would love to know if I am :)

  • I believe you missed the point. The ceiling mount does impart a spin of the wire and the bob, but only around the axis of the wire, NOT the plane of swing. The principle is that plane remains parallel in space. However, my highschool physics teacher taught me that to start a pendulum, you pull it off-center and let it go. As you hold it off-center, you are imparting earth rotation since you are standing on the earth, and hence would not appear to precess.

  • He said all museum pendulums are pushed backwards to "show" the effect.

  • Well, from what I've heard museum pendulums are a bit of a faker because they use some magnets placed inside the ball and in the ground, so that the magnetic force keeps the ball in motion, otherwise it would stop. There is not a thing in the universe that can swing by it's own without a force applied to it and in all museums the pendulums keep swinging like magic (air resistance and friction), or maybe it is perpetuum mobile? ;)

  • Also, since originally the wire supposed to be 100m long and the ball should weight about 80kg, then I think that the speed of the earth rotation would affect the long wire and distract the ball a bit from its course, causing the pattern to show up. Just like with those very high skyscrapers, where the speed of earth's rotation bends them a bit. It comes to me as the only one reasonable explanation of the problem with the mounting point.

  • I'm afraid you have your physics upside down. The bob would keep moving in the universe until a force is applied to it. Air resistance and friction are the forces acting on the bob & wire that would stop the swing. The magnets compensate by re-imparting energy, but not direction.

  • @geneous42 A pendulum, without any other device(such as a tosion spring) would not swing if no external force were applied, instead it would rotate around the point to which it is fixed (since gravity pulls the pendulum back down when it reaches its apex).

  • It is in English. This is a physics video, and it requires some level of linguistic and mechanical competence to understand what is going on.

  • This video is wrong. It purports to show the pattern that the pendulum would trace upon a paper in the laboratory frame, if it left a trace, with the characteristics being exaggerated for clarity. But it shows the "n-leafed rosette", while what should be shown is the "n-pointed star". In other words, if the pendulum is released from rest in the laboratory frame - which is the only practicable procedure - then it does not pass over the central point at all. It bypasses it.

  • say it in English please... for regular people, you have to remember that you're leaving comments on YOUTUBE, not your average physics professor!

  • It's still a rosette it just doesn't go over the center

  • interressante, vou usar como trabalho

  • Hmmm, good point there. However, the classic experiment does not include any external forces. (The San Jose pendulum used a magnet for convenience because it was scaled-down with very little mass. The presence of a magnet was disclosed right on the interpretive display.) The mass and initial energy of Focault's pendulum were sufficient to demonstrate the concept before friction made it slow to a stop.

  • There was a pendulum like this in San Jose, CA, at the Rosecrucian Museum planetarium. It traced its path in a shallow pit of fine white sand, and was kept in motion by a small electromagnet.

  • Any magnetic force on a pendulum also applies a DIRECTION to the penduum making it INVALID to prove ABSOLUTE motion.

  • You just said that Foucault's un-powered pendulum doesn't prove absolute motion either. Why make the distinction if neither one can prove absolute motion?

  • Sorry, magnets used for this purpose have circular fields. Physicists do think ahead.

  • Can you show graphically how circular fields work?

  • Gijreb: Just imagine a cylinder magnet centered directly underneath the mount point on the ceiling. Then time the energizing pulse to be on as the bob approaches the magnet, but off as it moves away. All it does is add energy to the swing, not direction. Details like manufacturing tolerances being quite small relative to visible motion dimensions is left to the student as a learning exercise.

  • Conjecture as to how the world works is necessary. When it leads to learning it is much more rewarding.

    To answer a question someone else asked, yes, I do have a college degree in Physics.

  • The Foucault pendulum tries to establish Absolute motion, which is NOT possible. Anyone who believes that it proves that the earth is rotating does not understand that all motion is Relative. We CANNOT know for sure if the earth is Rotating or Revolving.

    Foucault might have been a good technician, but he had NO clue about the nature of Motion.

    Any scientist still pushing this myth should be fired from their position.

  • I believe the satellites' continued observance of the earth over the Cold War have proven whether or not the earth is revolving or rotating.

  • How does the motion of a satellite prove that the earth is Moving??

  • Even if he didn't prove absolute motion, he proved the relative motion of the Earth to the Sun. It doesn't say anywhere in the description that he was trying to prove absolute motion. If you want to ascribe that to this experiment, go ahead. It doesn't take away from the fact that the Earth rotates about its own axis with respect to any other point that we can see.

  • Absolute motion is not implied, just motion relative to the "fixed stars". And yes, the definition of fixed stars is changing due to background radiation measurements. The principle still applies, however.

  • mbkheklmet come on then!!!! I'll take you anyday m8!

  • /

    hey, I live in Mexico. Anyone knows if there are any foucault pendulums in mexico?

  • No man, no se de ninguno...

  • Sale, mil gracias. me entere de uno que hay en queretaro. habra que darse una vuelta por ahi y preguntar exactamente donde está.

  • dapirategirl, we can't feel the earth rotating because of inertia, or the lack of it in this case. when you are moving along with something, it appears and feels stationary; just like if you were in a jet plane as it is traveling at over 500 mph, and got up to walk around, you wouldn't be slammed against the back because you're moving at the same speed.

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