Activity Overview
In this experiment you will be able to watch the fluid absorb into the paper towel, travel up through the paper towel and eventually cause the water from the top cup to complete empty into the bottom cup. Paper towel is absorbent. Paper towels are made up of cellulose fibers which are present in plants. These cellulose fibers are actually giant molecules that consist of many small molecules that are joined together. As the paper towel absorbs the liquid, the liquid is pushed along the paper until it runs out of space and runs off the end of the paper into the cup below.
The addition of food coloring is not essential to this experiment but it is fun to watch what happens to the color water as it moves through the paper towel. We used purple in one of our cups and we were excited to see that he blue actually was separated from the purple and the water in the bottom container is blue, not purple. So if you aren't interested in the color, this experiment can also be accomplished with just one set up of two cups.
Materials Needed
- 6 plastic cups
- A couple of connected paper towels torn in three strips
- Water
- Food coloring
How to Do It
- Fill three of the of the cups water and set them up on top of a few inches higher than three empty cups. You can achieve this by placing the cups of water on top of a shoe box or something comparable to give it height.
- Drop a few drops of food coloring into each cup and stir each one well.
- Keeping two paper towels together at the perforation mark, tear the paper into three long strips.
- Place a strip of paper towel from the top of each cup, ensuring it touches the bottom down to the lower cup.
- Now watch what happens as the paper towel absorbs the water through the paper and it moves the fluid into the lower cup.
