The Magic Ping-Pong Ball
One thing Skinny Dakota isn't good at is ping-pong.
On one Saturday afternoon, after you manage to beat him in seven straight games of table tennis in your basement, he reaches into his pocket and produces a twenty-dollar bill.
"Keep your twenty," you say, "we weren't betting on this game."
"I know, but I have a wager."
"I'll wager it's not going to be on the next game," you comment.
"You'd be right. But I think this bet will intrigue you. This double-sawbuck here says that I can levitate this ping-pong ball for thirty seconds in mid-air."
You pause; Skinny makes a lot of sucker bets. But as a gentlemen gambler, his victories seldom rely on trickeries of the language. "So you're betting twenty dollars that you can cause a standard ping-pong ball to float in air for half a minute? What are the conditions?"
"For at least thirty continuous seconds, nothing will touch the ping-pong ball but the air in this room. Nothing will be between the ball and the floor but air, and nothing will be between the ball and the ceiling but air. The ball will not be in free-fall: for the duration of its levitation it will remain between four and five feet above the floor. The ball will not be damaged. I only have three requirements."
"First, I will need some equipment. But this will be ordinary equipment I'm sure I will find in your house. Second, you may observe the experiment, but you may not interfere. Finally, you must play Ravi Shankar on the hi-fi."
You're convinced that Skinny doesn't possess any mystic powers. You're also convinced that Skinny wouldn't make this wager unless he knew he could win. But you're willing to shell out twenty dollars to see this trick. You slap your twenty on the ping-pong table.
"OK, what's this equipment you need?"