At 06:32 am 20-03-05 +0000, you wrote: >The Foucault Pendulum is a fascinating thing. >I suppose the best place to observe one is at >the poles where the complete rotation can be >seen. Indeed, in summer time at the north pole >it would be even more weird since it would be >turning in time with the sun. I'm sure the >ancient egyptians who worshipped the sun could >have made something out of that. > >I have always felt a bit sorry for people >living on the equator since a Foucault Pendulum >wont work there. Musing on their misfortune I >came up with a pendulum which would. Namely, >a compound pendulum of infinite effective >length; what one might describe as an Equatorial >Foucault Pendulum (EFP) > >As Vorts, doubtless, are well aware the effective >length of a compound pendulum is given by the >formula, > > L = I/(Md) > >Where L is effective length > I is the moment of inertia about > the pivot point > M is the mass of the pendulum > d is the distance between the body's > centre of mass and the pivot point. > >Where d equals nought, L equals infinity. > >So if we have two very heavy balls at each end >of a long lever arm which is pivoted exactly >at the centre of mass then d = 0 and, effectively, >we have a compound pendulum of infinite length. > >Now if we set up the EFP horizontally at the >equator with the lever arm aligned in a east >west direction, as the earth rotates the EFP >should describe a vertical circular a rate >of 15 degrees per hour. > >If the beam was released at sunrise the eastern >ball would rise with the sun and follow it round >the sky eventually setting as the sun set. One >could paint the eastern ball gold and the western >ball black. I'm sure the African witch doctors >would love it and it would give a whole new meaning >to the terms Golden Balls and blackball. > >I suppose if you made one big enough you could >actually extract energy from it - at the expense >of slowing down the earth a bit. Still, it would >be a favour to all those born on the 29th of >February to get rid of the leap year. One might >even slow it down to the Babylonian 360 days, >which would be rather neat. > >I can't see any snags to an EFP working in principle. >Perhaps Horace can. ;-) > >Cheers > >Frank Grimer >
Of course, the only problem is that when you initially set the EFP up in the first place, it would already have the same rotational spin as the earth and one would have to give it a shove to eliminate this rotation relative to the fixed stars - which would rather defeat the object of the exercise. 8-( Back to the drawing board. ;-) Since the first suggestion was a lot of balls given too much latitude I think we should hammer them into a disk and spin it at high speed longitude-wise We can still use our gold leaf to paint a face on a false front hiding the interior spinning disk and black paint for hair on a false black. That should provide some powerful voodoo for the natives. We could call the little yellow idol, Sunny Jim, after a brand of cornflakes I remember before they disappeared in WWII. I wonder if they ever came back again. Cheers Frank Grimer
