Sink or float is a classic preschool activity. You gather an assortment of items and have the children guess which will sink or float, and then test their hypotheses. (It made me laugh not too long ago when David Letterman added a gag segment called “Will it Float” with a huge pool of water and random items for the members of the audience to make predictions about. I’m guessing he’d been to his little boy’s preschool the day he came up with that one!)
