You make volcanoes out of it...that's what!
Parker came home from school with a recipe for clay volcanoes. You shape a volcano out of clay or play-dough and then add baking soda and a little bit of cider vinegar. Sit back and watch it erupt! Parker came home telling me how to make it exactly. It took him 10 minutes to get the full verbiage out and then I went through his back pack and found the actual directions from the teacher.
Our play-dough got a little gooey towards the end and the directions say to use clay if you want them to last. And then my husband informed me that my volcano wasn't the right shape and that is why is didn't erupt that much.