This is what happens when you microwave a bar of Ivory soap! Then you can tear it up, color it, and mold it into shapes! It's not wet and messy, either! This is awesome!
Science Fair Project Ideas for future reference
Weather: Fill the cup with water. Put shaving cream on top for a cloud. Explain that when clouds get really heavy with water, it rains! Then put blue food coloring on top of the cloud, and watch it rain. Kids love experiments!