Getting hold of a staple gun, then staping someones school bag to the wooden floor of the 6th form center IS NOT funny. Especially when the hairy gorilla type it belongs to yanks the bag so hard that it rips some of the floor up!
THEN stapling it to the ceiling the next day is also not to be encouraged.
Fill a beaker up with water, then put some acetate over it, invert it (carefully, not spilling any, then put on a shiny surface (dinner table?) and remove the acetate. Sit at ANOTHER tble, then wait to see who picks it up. This can be made more entertaining by having a number of inverted beakers, with only some filled with water. Sort of russian roulette?
Anyway, back to work....
Si