Mr Prothroe (who bore a startling resemblence to Nintendo's Mario) would conduct a physics class offering a combination of both science AND eye-opening anatomy. He would explain the theory of drag/wind resistance via a blackboard diagram consisting of a rather well endowed woman at the top of a diving board, succumbing, by the forces of drag etc, to the loss of her swimming costume as she fell faster towards the water. Each stage of cozzie loss was drawn with the precision of an anatomy textbook, Mr Protheroe's tongue peeping out through concentration as he did it.
Looking back, this could have been a stroke of genius from a master educator, knowing that the only thing that interests 13 year old boys, is naked ladies.
Saying that, he also used to tell us about how his dates would go on a friday night in rather more detail than we'd have liked. Obviously a 60 year old man who bears a striking resemblence to a certain italian plumber can get a lot of action over Merthyr way... *shudders*