Foucault Pendulum

[fergman90000]

hi, i have a question, what keeps it moving, should it eventually stop swinging because of friction & air resistance?? just wondering, thanks

[maxwellsdaemon7]

@fergman90000 Good question. There is an electromagnetic mechanism at the top that gives the pendulum a periodic "tug", to keep it from slowing down.

[jorge210594]

hi, i have a doubt. i wanted to know in what or where can we find a foucault pendulum...i have searched and realized that the largest ceiling clock is a foucault pendulum and also it is used in seismographers, but i wanted to know in what else...please answer me back as soon as possible

[maxwellsdaemon7]

@jorge210594 Hi there. I guess you can think of a foucault pendulum as a large ceiling clock. The foucault pendulum is special though, because it has to pivot freely at the top, such that the plane of the pendulum's swing can rotate around the vertical. I am not aware that foucault pendulum is used in seismographers.

[SpasticatedCunt]

FAKE

[BigLebowski2000]

I know on the North Pole it's 15 degrees p/h and more to the south it swings slower, on the equator it stands still, and then further south it swings again but in the opposite direction. On the poles it takes 24 hours (a little less) to make a perfect circle, but in paris it's 30 hours or something. But in paris a days also is 24 hours so? That's the part I don't understand. I am no physics expert, so please can someone explain me (in simple words, lol) why this is? Thanks ;-)

[1D0N]

I'm no physics expert, so this is why I ask this: What I don't understand is how the plan in which the pendulum swings changes like it does. I know earth rotates of course, but the point the pendulum is hanging from, is fixed, just like the floor with the pins. My guess is this only works if the cable is fixed to the ceiling in such a way it can freely rotate around it axis. Otherwise it could never swing freely,

[maxwellsdaemon7]

@1D0N Your guess must be right.

[migencluz]

@1D0N it is just a piece of string. Imagine tying a marker to a string and place it on top of a piece of paper. Swing it as you rotate the paper slowly... that is how I remember it.

[LordTharrion]

@1D0N It is suspended from a bearing in the cieling which does precisely as you have assumed

[TheBlackWhirlwind]

It's fascinating stuff, but my maths is not very good (it used to be better than it is now, asI have not used it in many years). I certainly do not question that Houston Texas is circa 33 degrees North on the map, but how do you work out from the number of rotations (180 degrees in 24 hours) that it indicates the latitude of that location to be 33 degrees. I heard if a pendulum swung at 90 degrees North, then number of rotations is 360 degrees/24 hours. So 180 degrees/24 is 45 degrees North?

[maxwellsdaemon7]

@TheBlackWhirlwind Hi there. Good question. It is true that at the north pole, the pendulum's direction of swing makes a full rotation (360 degrees) in one day (24 hours), while at the equator, the pendulum's direction of swing does not change (or it changes very very slowly). So for latitudes in between the north pole and the equator, the rotation in one day is somewhere in between 360 and 0. The interpolation is not linear though ( as you suggested with 180/24). It is in fact 360*sin(L).

[mrcodyhastings]

its the coriolis effect

[ravikantbpl]

is it automatically running ??? if so than we can create a motor which can run automatically widout electricity diesel or petrol...

[maxwellsdaemon7]

@ravikantbpl Hi there. The pendulum needs electricity (supplied to electromagnets) to keep it swinging.

[SollicitationisC]

Crimen Sollicitationis

[pmsteel67]

It's in lost!

[MoonNighto]

who invented it??it amazing invention..

[maxwellsdaemon7]

@MoonNighto inventor was a French physicist, Léon Foucault.

[Ashitaka1110]

Thanks for uploading, I've been to the HMNS on about a zillion school field trips, but it was never really close to knocking one down LOL.

[skillkill007]

Hey, me again. Want to know if the pattern of the pendulum corresponds with the rotation of the earth? If so the earth's rotation could influence the movement patterns of something smaller than the pendulum like the patterns of electrons around the atom. Could this be true? And can you please tell me who the guy is that determined the earth's rotation and give me links to his research.

[maxwellsdaemon7]

@skillkill007 I do not know who discovered that the earth is rotating about its axis. It was probably something known to the ancients (e.g. the Greeks). Maybe you can look up the name Leon Foucault in the internet, who, with his pendulum, demonstrated experimentally that the earth was indeed rotating.

As to the pattern, the period and direction of rotation of the plane of oscillation can tell you the distance from either pole, but only after many many swings.

[maxwellsdaemon7]

@skillkill007 Gravity has a very minute effect on electron motion around an atom.

[xZoggx]

@skillkill007 coriolis



[archolman]

@skillkill007 You have just asked the question that has physicists around the world baffled, that is, the difference in scale of the effects of gravity compared to the the electro-weak & strong forces.

If gravity was comparable in force, the Universe would probably not exist in this form. CERN is an attempt to examine the problem.

[skillkill007]

Hey, I'm considering to do an expo project on Foucault's pendulum. What i want to know is how can this very significant, symmetrical movement of the pendulum be implemented for industrial use? We can predict the movement and the time it takes to complete, how can we use this for our advantage in some kind of new invention?

[maxwellsdaemon7]

@skillkill007 Good question. I am note aware of an industrial application for the Foucault pendulum. But it does show, or verify, beautifully that the earth is a rotating frame of reference by its cumulative effect on many swings of a pendulum. You can use the Foucault pendulum to determine your latitude on the earth by how long the plane of the pendulum makes a complete revolution, but there are more efficient ways to do that, i.e. looking at the position of the sun or the stars.

[TheTombs13]

what i wana know is who puts all the little things back into place lol

[Dirtboy101]

This looks exactly like the one in the LA natural history museum.

[ENOCH1611]

i saw this pendulum in dc 30 years ago

[thaiholze]

its magnets that keep it moving or something of that sort. They are in the base

[almalinda06]

I love this, but I have one question--can anyone tell me how the pendulum keeps moving through out the entire 24 hours? I mean, doesn't it lose momentum, slow down? And they can't exactly give it a push, because it would ruin the integrity of the 'experiment' right? Because that would probably alter the pendulum's course... Unless its oscillations are mechanical? Sorry if this is stupid, I just honestly don't know..

[maxwellsdaemon7]

Good question. The oscillation is sustained by an oscillating magnetic field applied near the top. For the rotation of the plane to truly reflect the rotation of the earth, the magnetic field can only be applied so as to sustain the oscillation in the plane of the pendulum's swing, not to make the plane itself rotate, which is what I believe is the case with all Foucault pendulums.

[almalinda06]

thank you so much!!

[KeswickCamp08]

@almalinda06 theres a magnet under it, as the this passes the magnet switches off, and as te thing falls back, the magnet switches on, the magnet causes momentum enough for the thing to go passed when its turned off.

[marctoro96]

@almalinda06 Because its such a heavy weight, and the join supported from the roof is a BALL joint so its free to go anywhere. Very little friction is made here.

[ymom11]

@almalinda06

If there was no friction the pendulum would keep moving but here it is helped by a machine at the very top of the pendulum that keeps it in motion all day. It does not cheat tho, the wood being knocked down is caused by the earth's rotation. I saw a pendulum at COSI exactly like this one. I know that pendulums keep going forever...if there is no friction. But I saw the little machine at the top and understood.

[viledecon]

the pendulum swings on the same plane the whole time. it is the earth underneath it that is spinning. at the north pole it would spin 360 degrees in 24 hours(roughly) at the equator it would spin 0 degrees because on the equator there is no rotation. everywhere in between would have a different degree of rotation in 24 hours. the closer the the north pole or south pole, the higher the degree of rotation of the earth. its somewhat of an illusion. so to speak.

[fidoda007]

For those wondering, it's the Coriolis effect.

[archis84]

I dont get this. Why the pendulum does not go back and forth in one plane, but does go back and forth+side? I though gravity pulls straight down, ahhh

[maxwellsdaemon7]

Hi there. The plane rotates because the earth is rotating. If this pendulum is at the north pole, you can clearly see why: the ground rotates once every 24 hours.

[archis84]

Well I understand - the pendelum is pushed to the side becouse there is acting some force (x) on it (becouse of some earth rotation acceleration). How do you calculate this x? Does this prove if you travel by plane in this direction x you spend less fuel then flying to other directions.?

[maxwellsdaemon7]

I suppose you can consider the rotation of the pendulum plane to be due to a fictitious force (x). However, this force rotates with the plane of the pendulum (perpendicular to the velocity of the pendulum weight) so I don't think this kind of force can help a plane save fuel.

[wilsonnkwan]

@maxwellsdaemon7 So you are saying that it's like supposed we jump high enough from earth or may be we keep jumping, assuming that the observer is static, we will somehow land on not the exact same place because the earth is rotating (moving)

[maxwellsdaemon7]

@wilsonnkwan if you jump high enough, or stay airborne long enough, the ground below you should shift. This gets more pronounced as you get closer toward the poles.

[sylfamas]

@archis84 well the pendulum swings in the same direction (for example N-S) but because earth is moving, the ground underneath is moving as well :) . The pendulum rotates too (the actual bob) but of course it's circular and you can't notice it coz' it's slow, and that's why it's so cool. If you film it 24 hours and then play it fast (like 1 sec = 1 min) you would see the ground rotating while the pendulum swings in the same direction

[henkiis]

Cool man, where is this museum actually? I have read about this in Eco's book, amazed by that.

[henkiis]

I see now its in houston. I thought it was in Europe

[sydneysaurusrex11]

Ahhh I so looked at this last weekend ha! :)

[maxwellsdaemon7]

Cool!

[badbehaviourTV]

Can you tell, if this pendulum is moving by itself or do you have to put it in motion to observe this phenomena?

[maxwellsdaemon7]

I think there is a mechanism that uses magnets near the top that keeps the pendulum swinging. The rotation of the plane of oscillation of the pendulum is purely due to the rotation of the earth.

[dpmduran]

Is this the biggest one?

[tshalverson]

That's some pretty exciting stuff

[maxwellsdaemon7]

Yes, it was.