Here's what you need:
* shaving cream
* food coloring or acrylic paint
* white cardstock paper
* shallow tray
* ruler or something smooth for scraping
* aluminum foil or waxed paper
* old washcloth, rags or paper towels
Here's what to do:
1. Squirt some shaving cream onto the tray. Allow your child to smooth it out.
2. Put a few drops of food coloring or acrylic paint onto the shaving cream. You don't need a lot, maybe 4-5 drops at most. Drag a toothpick or plastic knife through to swirl the color.
3. Place the cardstock down onto the colorfully swirled shaving cream. Gently press down so all parts of the paper is "dipped" in the shaving cream.
4. Carefully lift up the paper and put on the piece of foil or waxed paper. Using the edge of the ruler, carefully scrape off the shaving cream to reveal your marbleized design. You can reuse the shaving cream a few times before the colors get too muddied and you'll want to make a fresh batch.
5. I kept a big bowl of water and some old washcloths on the table to wipe off hands and the ruler in between uses. You might want to use smocks for this activity, because the food coloring WILL stain, but it really was fun and worth the mess. I think it might be cool to use the marbleized paper to make notecards, since the kids wanted to make several sets of their fancy new paper.