Capillary action. In simple terms, water really likes to wet certain surfaces e. If you have lots of wettable surface area per volume of water, then the water can be pulled up quite a distance. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group.
Create a free Team What is Teams? Learn more. Why does a paper towel absorb water upwards? Ask Question. Asked 6 years, 2 months ago. If you look closely at the surface of a paper towel, you'll see that it's full of tiny pores and holes, somewhat imitating a sponge.
In fact, many super-absorbent towels are designed to be more sponge-like in their fibers and construction than cloth weaving, because by imitating the sponge's shape, the towel can have the same absorbent power. These many tiny holes and gaps between the towel's fibers can hold water due to surface tension, also known as wicking action or capillary action.
Capillary action is the small amount of elasticity that naturally occurs between molecules of water, holding them together. Every little space in the surface of the paper towel has its own tiny "bubble" of surface tension. These bubbles are formed when the towel comes into contact with liquid because the liquid in each tiny space is kept separate from the liquid in other pores and pockets.
This allows the bubbles of liquid to be held in place and even sucked upward because each pocket contains so little water that the intermolecular attraction is stronger than the gravitational pull on the liquid. Accessed June 29, A Moment of Science is a daily audio podcast, public radio program and video series providing the scientific story behind some of life's most perplexing mysteries.
Learn More ». Give Now ». Noon Edition. The next time you reach for the paper towels, remember to fold! You might feel good knowing you just saved an extra paper towel from being used. This activity brought to you in partnership with Science Buddies. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options.
Go Paperless with Digital. Key concepts Absorption Paper Water Molecules Introduction We all know that washing hands throughout the day can help keep colds and flu at bay. Materials Five or more identical paper towels—preferably the type in public restrooms In case you would like to test different types of paper towels, choose at least five identical towels of each type.
Do not worry about wasting a few towels—this activity might help save paper in the long run! Water Place to hang a paper towel to drip Kitchen scale, one-gram precision or better Paper and pen or pencil for recording weights A workspace that can get a little wet Scissors to make towels smaller for small hands optional Preparation Assemble all of your materials at your workspace.
Procedure Unfold the first paper towel if you have the prefolded type. Wet it thoroughly and hang it so all of the excess water drips out. When the towel no longer drips, weigh it on a kitchen scale. You can heap up the towel on the scale rather than neatly folding it.
Record the mass on a piece of paper. Fold an identical paper towel in three if it was not already prefolded and fold it one more time so six layers of towel are on top of one another. Wet it thoroughly and hang it—still folded—so all of the excess water drips out. Do you think this folded paper towel holds more, less or just as much water as the unfolded paper towel?
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