This experiment took up most of our afternoon. It was so fascinating and my son termed it "sorta like rain", which is so true. The density of the water is more than the shaving cream so the colored water seeps through. On top of all that, the shaving cream resembles clouds! Anyway, all you need for this is a clear tub, shaving cream, colored water and some droppers for dripping the water on. We poured water into the tub, filling it about half way. Then covered the top with shaving cream. After that we dripped the colored water on top of the shaving cream and watched the magic begin. It is fascinating when the colors begin to seep through. The pictures do not do it justice. Of course, you can always make some cool prints by pressing paper onto the top of the colored shaving cream and then wiping off the shaving cream. Makes a neat marbled pictures.