Marbled Wrapping Paper Physics Experiment

Food coloring is hydrophilic, meaning it’s “water loving.” When in water, the dye spreads out. However, if it’s dripped on something that is hydrophobic, or “water hating,” it can’t spread around. The soap bubbles in shaving cream aren’t hydrophobic or hydrophilic, but somewhere in between. This means the food coloring can sit on the surface as it is mixed and swirled. The wrapping paper is hydrophilic. So when the dye hits the paper, it stays there and moves around, which makes an even more marbled pattern. Since the shaving cream isn’t particularly hydrophilic, it can be scraped off the paper without removing the dye. When the paper dries completely, it makes an interesting paper in which to wrap gifts! Music: http://www.purple-planet.com