We're having a special visitor next weekend - the Journal of Irreproducible Events, the esteemed (?) magazine of humor in science. As a part of the irreverence, I'm hoping to put on an improbable science show, featuring silliness like giant bubble monsters and clock reactions. Can anyone suggest a fun, fairly low-mess demonstration they would include on such a distinguished program? Thanks for any suggestions, Jim Moskowitz -Public Programs, The Franklin Institute-