Have you ever wondered why paper towels are so good at picking up water when we have spills? Well, wonder no more! The reason paper towels can work really well to pick up water is because of something called capillary action.
Capillary action happens where there are small or narrow spaces that water can flow into. This helps paper towels absorb the water when it is spilled. Sometimes, water can even defy gravity while flowing into these spaces. However, the reverse is also true. If we spill a liquid that is thick and gooey, like syrup, the paper towels may not work as well because there is less water.
- 3 Small Cups or Jars
- 2 White Paper Towels or 1 Square Paper Towel
- Food Coloring
1. Place your cups in a straight line.
2. In the two outside cups, add water until they are about half way full.
3. Add food coloring to the cups with water. Choose a different color for each cup.
4. If you are using a square paper towel, you will need to cut it in half before the next steps.
5. Fold one of your paper towels lengthwise twice. You should have a long thick strip. Repeat this step with your other paper towel.
6. Place one end of one paper towel strip into the left cup with water, and the other end into the empty middle cup.
7. Repeat step 6 with your other paper towel and the cup on the right.
8. Let it sit for a little bit and see what happens!
What’s happening? Paper towels are made from cellulose, a substance found in plants (paper products come from trees!), which is hydrophilic. When an object is hydrophilic, it means that it is attracted to water.
When plants need water, they are able to use capillary action to bring water up through their roots and spread throughout its stem, leaves, flowers and/or fruits.