This first experiment had the potential to being really neat, but alas, we did not have the right "ingredient". The idea was to place dried beans in a small plastic container, add water, and place the lid over it. We hypothesized that the beans would soak up the water and increase in size. The added volume would cause the lid to pop off.
Well, it kind of worked. We did not have any beans, so I used split peas (or lentils? I don’t recall) instead. They cause the lid to expand, but not pop.
The second experiment was to see how water affects sugar. We colored the water blue so we could see how it climbed up the sugar tower. We added way too much water and caused the sugar tower to dissolve quicker than anticipated. It was still fun. I took video, but am having problems uploading it.