A cork, say from a wine bottle, is held by a robotic clamp at the bottom of a bucket of water and released the moment the bucket is dropped off the side of a tall building. What will happen to the cork during the fall? Will it float to the top of the bucket normally, slower than normal, faster than normal, or not at all?

Assume that there is no air resistance to slow the bucket down.

When in free fall, any object is acting the same as an object in orbit, as that's what an orbit is: free fall. To "simulate" (actually replicate) zero-g conditions, astronauts get some training in a plane they call the "vomit comet", which is flown on a parabolic arc, the same as if it were in free-fall in a vacuum, and the occupants feel the equivalent of zero-g (relative to the walls of their container).

In fact the parabolic arc of a thrown object in a vacuum is parabolic only if we consider the ground to be flat. It's really a piece of an ellipse--an orbit. Anything within it perceives zero-g relative to the walls of the container.

So as for gravitational effects, the cork would not float to the top. Of course there might be random eddies in the water, thermal fluctuations causing pushes here and there, and tiny effects of Brownian motion, but no gravitational effect within the bucket with regard to the walls of the bucket.

Posted by Charlie on 2003-03-26 07:55:17