What exactly is a fault bucket and what causes it?

Newton's bucket experiment?

• I've recently read a description of Newton's bucket experiment and how it supposedly proves absolute space. Can you help me answer a few questions about it? Also, if I misunderstood the experiment, could you explain where I am doing so? The bucket filled with water is attached to two ropes on each side of the bucket which is hung from something. When the ropes are wound up and released, the spinning bucket at first has no effect visible on the water, but soon it causes the water to spin and turn into a concave shape as water climbs the sides of the bucket's walls. Supposedly, when you stop the bucket, the water will continue to spin in a concave shape, essentially moving relative to the bucket at the same velocity as when the bucket first began to be wound up. The fact that because the water and the bucket are moving the same speed relative to each other and yet the shape of water in both situations is different is supposed to prove absolute space. But aren't there a few problems with this? First of all, when the bucket first began to be wound up, the water didn't have much time to have the kinetic effects of the bucket transferred to it, where as when the bucket was stopped, it had already been spinning for a while? Also, why do we have to assume the water is accelerating relative to absolute space instead of the surroundings of the water outside of the bucket. Isn't the water accelerating relative to the outside world, the thing that caused the bucket to start spinning in the first place?

• Answer:

  I am not familiar with this experiment. I surmise that it is supposed to prove an absolute reference for angular velocity, which is not the same as absolute space. Suppose the bucket is suspended from the roof of room, and the room is spinning relative to the Earth. How could you determine the speed and direction of the room's spin without looking outside? What difference would it make if the bucket is suspended from a point away from the axis of the room's spin? What if the room is at the end of the arm of a giant centrifuge? The surface of the water in a spinning container takes the shape of a paraboloid. That is how large parabolic mirrors are cast. In the reference frame of a room in a centrifuge, a fluid floor would take a parabolic shape. The surface of the water in the bucket would also be parabolic. Would both parabolas have the same axis of symmetry when the bucket is spun relative to the room? I leave you to ponder those questions and their implications.