Diet or Regular Cola?
 

Get 2 or 3 cans each of regular and diet cola and cover their labelling (don't let anything show that would give away which is which!) with paper and ask the kids to tell you which is diet cola and which is regular. Let them hold the cans, open one of each and let them smell the drinks and see if anyone can guess. :idea:

To find out, fill a bucket with water and drop one of each can in, then wait an few seconds.......the floating can is diet and the regular is the can that sank. :magnify:

The reason for this is simply sugar - it's heavier and because the diet version contains no sugar.......that's right - it floats! :cheerful: