I've been seeing the Ivory Microwave Experiment on blogs for years and have been meaning to try it. When the girls got ivory soap for soap carving at the art museum, this experiment is the very first thing that came to mind. First I invited L and E (almost 5) to place two different brands of soap in a bowl of water and observe what happens. The Ivory soap floated, and the other brand did not. The girls predicted that it was because it was lighter, but then were not so sure when they felt the weight of both bars in their hands (I should have brought out the scale so we could compare them). I asked some prompting questions to get them thinking about how some objects that are filled with air float...
