Physics Demonstrations by Jearl Walker One of the highlights of CEC-78 was the general session where Jearl Walker showed his confidence in science by performing physics demonstrations that contain some element of risk. He plunged his hand into molten lead and brought it out without damage (this demonstrates that moisture on the hand turns to a vapor and prevents more serious damage). He lay on a bed of nails to show that the pressure per area for each nail point was less that the strength of the skin. He even had a cement hlock hroken witha sledge hammer on the top "slice" of a bed of nails while he was sandwiched between two beds of nails. Guilford High School Rockford, Illinois 16111
188 1 Journal of Chemical Education
While he did not demonstrate walking on a bed of coals, he explained why he got 2nd degree burns the last time he tried it, although he had successfully demonstrated the phenomena twice before. In addition, he showed and explained how other demonstrations can be used to teach and to have students look forward to coming to class. In case you have let your interest drop in the "Amateur Scientist" portion of ScientificAmerican, you may wish to reinvestigate the series as Jearl Walker is writing it in his unique and interesting way. Douglas D. Smith
