We didn't have to do many pranks in the physical science labs, because of our teacher... dear ole chap, he was just too kind-hearted to get along with pupils... and he was a real bugger with experiments... I remember the day when he dropped and broke first the fog chamber then the big plug-it-together-electro-motor. recently he had also used up all the little lamps, and we heard his colleague coming from the other lab into the storage, find the remnants of the motor and shout through the closed door: "Mr. H. come here RIGHT NOW!" Later in the day this colleague told us: "I am REALLY pissed... seems to last long today..." Well, I needn't to explain what he did with the great basin. Or what happened with the rubin laser. Unforgotten the day when he wanted to show us a weak alpha ray preparate and the geiger detector didn't make "Click... Click..." but "Scrchhhhhhhhhh...". Mr. H. looked to the sign and was so shocked finding the strong gamma ray preparate he was not able to srew it into it's leaden safety cannister. We were innocent. Really. he did this all alone. But his greatest moment was when he wanted to explain fuses to my brother's class. This genius of a teacher went out to the store and came in a moment later with ALL fuses from the fuse box. Shortly after another colleague came in and asked "Do you know why we have a failure on the whole floor? It's REALLY bad timing, for we just have general degree exams next room, and the experiment broke down in the middle of the progress..." Mr. H. looked at the heap of fuses... "Oh, ah, well... " And in the end he and his colleague stood in the store with flashlights and couldn't find the right places for the right fuses. There was no light, of course. The other teacher only shooked his head and sighed. Poor Mr. H., for he was a teacher that really loved his pupils.