Why does toilet roll absorb water?

In summary, when you place a piece of paper so that it is just touching the surface of a bowl of water, the water will move up the toilet paper.
  • #1
_Mayday_
808
0
Simple question but not such a simple answer. If I place a piece of toilet paper so that it is just touching the surface of a bowl of water, the water will move up the toilet paper. I know the paper is "absorbing it" but how does it work? What is making it counteract gravity?
 
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  • #2
One answer:

In large part due to capillary movement of water. Paper is made of wood fibers which are hollow. Diffusion also plays a part - diffusion of water from an area of higher concentration to an area of low concentration. -- wet -> dry
 
  • #3
jim mcnamara said:
One answer:

In large part due to capillary movement of water. Paper is made of wood fibers which are hollow. Diffusion also plays a part - diffusion of water from an area of higher concentration to an area of low concentration. -- wet -> dry

Thanks, yes that idea makes sense. I was thinking along the lines of what paper was made up of, as we are studying root structure in quite detail. Thanks for the feedback.
 
  • #4
I'm not sure how much Chemistry you've had, so I'll keep this kind of simple.

Wood fibers are tube-shaped cells made primarily from cellulose, hemicellulose, and lignin.

If you remove the lignin from wood fibers, you get paper fibers, also called pulp. Toilet paper is made from pulp. So pulp is basically tube-shaped fibers made from cellulose and hemicellulose.

Cellulose and hemicellulose are very hydrophilic, which means they have a strong affinity for water. This is because they have a lot of -OH groups. Water is attracted to -OH groups by hydrogen bonds. Hydrogen bonds aren't very strong, but the surface of each fiber has many, many -OH groups, so the water is held tightly to the paper fiber.

That's how absorption works when water is exposed to toilet paper.

(My first "real" job was in the Fiber Science lab at a large paper company.)
 
  • #5
Thanks lisab, that along with jim's explanation is what I was after. I couldn't get my head around it. People where saying a water potential gradient, but I don't think that would account for the water actually counteracting gravity, but more the attraction between th e -OH groups and the H bonds. Thanks!
 
  • #7
This is why nature took a page out of our book, and evolved trees out of toilet paper. If you doubt it, just take a sample of the wood from a tree; you'll see the very same structure of hollow tubes as is in toilet paper pulp. An excellent example of natural retcon.








:biggrin:
 
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  • #8
Dave -
What the heck is retcon?
 
  • #9
jim mcnamara said:
Dave -
What the heck is retcon?

Retroactive Continuity. A good example is when DC Comics effectively negated a huge series of earlier works (by calling them 'alternate reality' stories) in order to bring disparate factors into line. If would be the same if all Spider-Man stories now showed him with biological web-shooters in order to match the movies.
 
  • #10
Can anyone relate this to cohesion and adhesion, as I think this would be a pathway that would benifit my learning as that is what we are covering in class.
 

Related to Why does toilet roll absorb water?

1. Why does toilet roll absorb water?

Toilet roll is made of absorbent paper fibers that are woven together to create a soft and porous material. When water comes into contact with these fibers, it is drawn into the tiny spaces between them, causing the roll to absorb the water.

2. How does toilet roll absorb water?

Toilet roll absorbs water through a process called capillary action. The water is pulled into the tiny spaces between the fibers, moving against the force of gravity. This is due to the attraction between the water molecules and the fibers of the toilet roll.

3. Can toilet roll absorb other liquids besides water?

Yes, toilet roll can absorb other liquids besides water. The absorbent fibers in the toilet roll are designed to absorb a range of liquids, including urine and other bodily fluids. However, some liquids may be too thick or oily to be absorbed effectively.

4. How much water can a toilet roll absorb?

The amount of water a toilet roll can absorb varies depending on the type and brand of toilet roll. On average, a single sheet of toilet roll can hold between 7-10 milliliters of water. However, multiple sheets can be used to absorb larger amounts of water if needed.

5. Is toilet roll the most effective material for absorbing water?

Toilet roll is a commonly used material for absorbing water, but it may not be the most effective in all situations. Other materials such as paper towels or sponges may be more absorbent depending on the type of liquid and the surface being cleaned. Additionally, some toilet rolls are designed specifically for high absorbency, while others may not be as effective.

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