I bought ds a microscope for his 6th birthday. At first we looked at the prepared slides which came with it (pine needle cross section - pretty, onion - big cells etc) then progressed onto his choices (pond water - nothing, bogey - dull).
This evening I found two lice on ds3's head, picked them off and put them under the lens. OMG! Amazing. It looked just like this but better, hairier and moving. We could see its beating heart FFS! We could see the blood coursing through it's transluscent body. It was very exciting.
Actually I felt sorry for it because we were watching it die. Sympathy for the devil eh?