Oil and Water Rainbows

What you’ll need:

  • Clear glass dish
  • Small dishes, one for each color you plan to use
  • Food coloring liquid
  • Water
  • Oil
  • Drinking straws

We suggest using a glass dish with a flat bottom vs. a round bottom bowl. For oil, canola or baby oil work best, but you can experiment with other oils, as well!


  1. Fill each of your smaller dishes with water, and add 3-5 drops of food coloring to each.
  2. Cut the drinking straws in half, and place one in each colored water cup.
  3. Fill your clear glass dish with oil.
  4. Use the drinking straws as you would a pipette, placing the straw in the colored water and then placing your finger over the top of the straw.  Move the straw over to your dish of oil, then lift your finger, releasing the colored water into the oil. Be careful not to let your straw touch the oil, so you don’t end up with oil in your colored water dish. Avoid using a straw for more than one color, to keep the colors crisp.

What happens when you drop the water into your oil? Talk about how oil and water don’t mix. Experiment with dropping large amounts and tiny amounts of water. What happens when you stir the oil rapidly after colored water has been dropped in?

Check out other science and math activities from Camp Little Victors: