What you need:
- Paper towels
- Food coloring
How to do it:
- Fill 2 cups half way with water.
- Put a few drops of blue food coloring in one cup and yellow in the other cup.
- Take a twisted paper towel and place it in the blue water and the empty cup.
- Take another twisted paper towel and place it in the yellow water and the empty cup.
- Let sit for a few hours.
- The center cup will have water in it and will be green. (When you combine yellow and blue it makes the color green.