Re: What is water absorbancy?

Hi Nina,
Very simply put, water absorbancy is the ability of a substance / object to 
absorb water.

In paper towels, water is absorbed due to two phenomena. The first is 
wettability (which means the paper particles in the paper towel readily 
absorb water and get wet). The second is a sligthly more complex phenomena 
called capillary action.

Before we go on to understand capillary action, we must understand the 
differance between cohesiveness and adhesiveness.
The ability of a particle to closely bind with another one of its kind is 
called cohesiveness. This means that higly cohesive particles will prefer 
to combine with particles similar to themselves (as compared to other 
particles). Typically, a substance that has low cohesive strength will 
crumble, break or fall apart easily (such as sand). While that which has a 
high cohesive strength will be very difficult to break or separate (such as 
metal).

Adhesiveness on the other hand is the ease with which a particle of one 
substance will attract a particle of another substance. Adhesives can 
easily bind with other substances to produce firm and tight joints.

Now, coming to our question, paper has low cohesive strength (thats why it 
can tear easily especially when wet) and high adhesive strength (when in 
contact with water). That is why its difficult to remove water from wet 
paper. Moreover, paper has a lot of tiny holes or gaps in it. These act 
like pipes or channels for water particles to flow. So when paper is placed 
over water, it attracts the water particles, causing them to move into the 
small gaps in the paper.
This is called capillary action.

I hope this answers your question. If you need more help, feel free to 
contact me.

Nauzad