On 08/30/2015 03:40 PM, rbowman wrote:

My "cream my pants" idea would be to *levitate* BOWLING BALLS to
varying heights depending on the current time. Yeah, it's relatively
easy to do this with ping-pong balls, etc. What would make *this*
impressive would be the fact that lifting and suspending 8-10 pound
balls would, itself, be a significant technical challenge!


I had a professor who had a demonstration where he suspended a bowling
ball on about a 20' wire. He would stand on the side of the podium,
place the ball firmly against his chin, let go, and stand perfectly
still while the ball described its arc. It convinced first year physics
students he knew more about physics than they did.

The same guy was also known for firing off a model pulse jet in the
lecture hall. That convinced the students he was completely insane.

One of the aeromodeller magazines I had as a teenager had drawings for
making a pulse jet but unfortunately I didn't have the equipment needed
(lathe, for example) to make it. I've never even heard one, but the
description of its sound caught my interest. I guess my parents had
heard pulse jets (V-1s), and they were hardly going to encourage me to
make that sound again.

Perce