Ping Pong ball & Atmospheric Pressure experiment

To start, the bottle is filled about 2/3 full. You can hold the ball on top of the bottle and dip the bottle upside down and then bring it back up right side up. Now try to slow tip the bottle sideways to seal the ball to the bottle.

If this does not work then hold the ball with your fingers against the glass and the bottle tipped up. and tip it upside down. Hold the ball loosely against the glass so that water is allowed to leak out. Eventually the air pressure inside the bottle falls to a low enough value that the pressure on both sides of the ball is equal, and the hand can be removed.