The walking rainbow is a fun experiment for kids to set up and observe. Kids will be able to see the experiment starting almost immediately and then check back every 30 minutes or so to see things moving along. The walking rainbow experiment demonstrates a few basic scientific concepts – capillary action and color mixing.
Materials:
- Clear glasses – You will need an odd number of cups.
- Water
- Food coloring
- Paper towels
Instructions:
- Line the cups up on a table. Fill every other cup with water. Leave about 1 inch at the top.
- Add food coloring to the cups with water. Add a different color to each cup.
- Fold a piece of paper towel into thirds. You will need a piece of paper towel for each cup of water you have.
- Put one end of the folded paper towel in the colored water and the other end in the empty cup.
What’s happening?
The walking rainbow experiment demonstrates a few basic scientific concepts – capillary action and color mixing.
When the paper towels are rolled up and placed between two jars, they will demonstrate capillary action. Capillary action is how liquid can move up something, rather than follow the usual pull of gravity and pull down. This causes the water to move up the paper towel and into the next jar. Capillary action is how plants pull water from the soil and up into their leaves to keep watered.
Once the paper towels pull color from the base red, blue, and yellow primary color jars, the resulting mixture creates the secondary colors of green, purple, and orange, completing the rainbow.