Ball & tube mystery

You let the public see a metal tube. One can look through it. Then you put a metal ball on the tube. The ball is too large, it remains on the tube.

Then, when you wave your hand over the ball, you can see the ball very slowly into the tube bags. If you stop waving the ball comes back slowly from the tube.

Everything is then immediately display it off your hands. The audience can try, but it will not succeed.