This super cool walking water science experiment is so simple to set up and is an excellent way to demonstrate capillary action and transpiration to kids. My kids were totally amazed at the outcome as the water appears to move from one cup to another!
MATERIALS NEEDED (affiliate links):
Red, yellow & blue food coloring
Water
WHAT TO DO:
1. Start by adding water to three of the cups so that they are about 3/4 full of water.
2. Alternate each cup containing water with an empty cup and arrange them in a circle.
3.Then add a few drops of food coloring to each cup so that one cup is red, one is yellow and one is blue.
4. Next take paper towels and fold them in half or fourths to make long strips.
5. Link all the cups together using the paper towels by placing one end of each paper towel in each cup.
6. Wait several hours or overnight and watch how the water travels through the paper towels and mixes to form new colors. Amazing! 😲
This activity is great to do any time of the year but really fun to do in the spring for a rainbow themed activity.
WHY IT WORKS:
The water is able to move up and through the paper towel because of a process called capillary action. The water travels up the tiny gaps in the fibers of the paper towel. The water molecules are cohesive so they stay close to each other, but they also bind to the paper towel through a process called adhesion. This process is similar to the way water travels from the roots of the plants to the leaves called transpiration. The gaps within the paper towel act like the capillary tubes of plants and pull the water upwards.
Check out our experiment with celery to demonstrate transpiration!
Check out our other fun science experiments!