Have half an hour to fill? Try microwaving a bar of Ivory soap! Seriously! I saw it on Pinterest and my daughter and I gave it a try. We stuck a bar on a dinner plate and microwaved it in 30 second blasts. It fluffs up and expands while you watch! Then my daughter played with the soap in its new form, adding food coloring and whisking it up. We had lots of fun- give it a try!
Here’s the science behind what’s happening: http://chemistry.about.com/od/demonstrationsexperiments/a/soaptrick.htm