I can't see how REers can believe this Foucault Pendulum thing proves the Earth is spinning 1000 mph. Yet they also believe the Earth orbits the sun at 67,000 mph and it whirls around the center of our galaxy at 490,000 mph and yet with all this whirling and moving that pendulum keeps on swinging back and forth keeping perfect timing that proves to them that it is the real deal and is a perfect representation of the Earth spinning 1000 mph. In my head, I think that the pendulum would be swinging every which way because of the Earth's movement around the universe. I guess it is just me though.
Earth's rotation is the cause for the greatest change in rotation in space (space as in room) of objects on earth. It has nothing to do with accelerations or speed. And the only thing it proves is that earth is rotating. The reason the pendulum rotates, for you who have not realised it yet, is the pendulums rotation in space (space as in room) relative to earth. As the pendulum swings back and forth it swings along a certain 2-dimensional plane. As earth rotates it applies a rotating force on every object (that is in contact with the ground) on it that keeps those objects rotation stable relative to earth. The pivot of the pendulum is also subjected to this force, as is the weight, and the whole pendulum rotates with earth. BUT this force does not accelerate the pendulum in any direction, as the forces rotating the pendulum balance each other out. This means that the pendulum keeps it's motion. It's because there is NO force that changes it's motion, so it keeps it's motion along the same 2-dimensional plane.
Okay master, if you want to believe this contraption proves the Earth spins so be it. I just tried to reason some sense in you. You are simply a lost cause.
Can you explain using a flat earth why the foucault pendulum work then, which happens to also be the topic of this thread.
I will answer the topic of the thread like you ask.
The Foucault pendulum is a piece of scientific apparatus specifically designed and built to deceive and mislead. It is literally a “humbug” – a sham, a fake, a fraud, an artifice, a pretence, a hoax – and I believe it should be exposed as such. But the Foucault pendulum is more than a hoax. It is actually a religious propaganda tool. Most of the ones that do work are forced to do what they do, rather than doing what comes naturally. The only kind of Foucault pendulum which would not be a fake would be one that was free-swinging, operated properly without any gyroscope, device to guide the wire along a certain direction and anyone could simply hang a plumb-bob from the ceiling, give it a swing and it would swing back and forth in a circular direction long enough that a person could mathematically determine that if there were no air resistance it would theoretically travel a complete circle in twenty-four hours.
Gyroscopes ?
Gyroscopes...
Gyroscopes were invented by Foucault, the Foucault's pendulum inventor. Why ? To measure the rotation of the Earth. When ? One year after he built his pendulum. 
You can buy one if you want, so you could study the interior parts, and see there are no mechanisms inside designed to fake Earth's rotation.
https://en.wikipedia.org/wiki/Gyroscope
One of these tricky old pendulums requires care to manage, because imprecise construction can cause additional or retarded veering. If there is deficient animation, it will dampen the oscillation, so these pendulums incorporate a "little electromagnetic drive" or "other" to keep the bob swinging along in its unique patterns of swing, and some will be restarted regularly. They typically will have special rigging, recessed and hidden, at the top that will also help them to sway a certain way.
As Marshall Hall described the one at the Franklin Institute in Philadelphia, at the very top of the pendulum, next to the cable mounting, there is a small motorized pin that always stays horizontally opposed to the cable. This pin rotates very slowly (also as it depends on latitude), so as to always ensure the pendulum’s reliability when hitting the little radial teeth below, once every hour, as it swings back and forth; and the pendulum is cranked up every morning by the caretaker, or the monkey and the engineer.
The pivot mounting at the top permits the bob to waggle slowly over the cumulative degrees. There is a little ring through which the cable descends that determines the arc of the bob’s gradual swinging motions. The cable through the ring will become visibly off centered, after a while, and will be pulled to another edge from time to time, renewing a full swing, when the pendulum appears to be running down.
After being reset, the cable holding the bob can be seen to twist and jerk. Viewed up close, the bob can be seen to twist one way and then the other, like it has been wound up like a little swing on a playground and then let go. The little noticeable off-center positions of the cable, through the arc-controlling ring, are a feature which helps give momentum and bias in the direction of the slowly curving oscillations.
They may vary in some details of design, but, nevertheless, they are all driven, damped, and tuned. If they are not tweaked, the bob tends to lose its pattern, and it becomes difficult to see the precession. Thus Foucault pendulums are not truly free-swinging pendulums. They are damped, constrained, and charged up by design. Unlike other pendulums that anchor the weight in one plane, a Foucault pendulum allows the anchor to rotate. The pivot mounting at the top, at the suspension point, lets the weight swing in any of an infinite series of vertical planes. So the plane of the pendulum will rotate around a full circle over a given period of time.