De truuk op tv bij Uri Geller !
A striking demonstration. Place an ice cube on each of these two identical looking black blocks at room temperature. One ice cube instantly begins to melt and is totally gone in about 90 seconds. The other ice cube shows no evidence of melting whatsoever. Great for showing the difference in heat conductivity in different materials. This demo is simple enough for elementary students, yet of just as much interest to high school students and educators. Set of two blocks.