A colorful but simple experiment that uses common kitchen items.
Messy level: 1
(5 = Super messy. 1 = Not messy at all.)
- Clear glasses or cups
- Paper towels
- Food coloring
1. Position your empty glasses or jars about 2 inches apart. Pour water into each container until approximately 3/4 full.
2. Add a few drops of food coloring into the water and stir to combine. Be sure to use the same amount in each container.
3. Fold a paper towel to about 2 inches wide.
4. Place one end of the paper towel into the glass with the water and then place the other end into the next container.
5. Let sit and return periodically (every hour or so) to observe what has happened.
*If you don’t see much water movement, try adding more water to your cups. You may also want to try a different paper towel brand.
The colored water travels up the paper towel by a process called capillary action. Capillary action is the ability of a liquid to flow upward, against gravity, in narrow spaces. This is the same thing that helps water climb from a plant’s roots to the leaves in the tree tops.
Paper towels, and all paper products, are made from fibers found in plants called cellulose. In this demonstration, the water flowed upwards through the tiny gaps between the cellulose fibers. The gaps in the towel acted like capillary tubes, pulling the water upwards.
The water is able to defy gravity as it travels upward due to the attractive forces between the water and the cellulose fibers.