Physics Van 3-site Navigational Menu

Physics Van Navigational Menu

Q & A: Measuring Paper Towel Absorbancy

Learn more physics!

Most recent answer: 04/10/2009
How do you find the absorbancy of a paper towel?
- Laurel (age 12)
L.R. Green, Escondido, California
The way you would find the absorbance is to perform an experiment. When a scientist has something he does not know, he performs an experiment or series of experiments to determine the answer.

The absorbancy of a paper towel would be the amount of liquid a certain paper towel can handle without leaving excess liquid on the surface.

What sort of variables might affect absorbancy?

(a) temperature of liquid?
(b) density of liquid?
(c) brand of paper towel?
(d) type of paper towels?
(e) area of paper towel
(f) other factors?

To find the absorbancy, you’ll need to keep all of those variables constant while testing a single variable. So say you want to test liquid density, you would prepare several samples of paper towel (repetition is important), being sure that they are the same area, brand, and type of paper towel. Then you would add the liquid until the paper towel stopped absorbing it. When you found that point, you would record the volume of liquid you used. You would then repeat the experiment using the same liquid on several paper towel pieces as well as other liquids of different densities on the same paper towel piece. From that information, you can determine the absorbancy of a paper towel vs the density of the liquid being absorbed.

There are many different variations to test every one of the variables I mentioned. The key is to keep all variables but one constant and only change that one variable. Otherwise, you won’t know what caused the difference in data.


(published on 10/22/2007)

Follow-Up #1: paper towel ’science’

Will this be ok for a science project???
- Anonymous (age 15)
I've heard of science teachers assigning 'paper towel absorbancy' as a science project, but in my opinion: No, it's not ok.

Why? First of all, it's just too boring. You'll find that some absorb more than others. Do you really care? Second, there's no real interesting idea to test. There's nothing that could lead you on to another project.
Maybe you could make an interesting project about social science out of this, if you have some question that you really want to answer. For example, you may wonder whether expensive, highly advertised brands actually absorb more than cheap ones. Or you may wonder whether spending $1 on lots of the cheap brand buys more total absorbancy than spending $1 on a little of an expensive brand.  Those might be of interest to a consumer or someone interested in economics or how people's opinions can be shaped.

Real science has some excitement to it, and ideas that tie together to make a big picture. It's not just a collection of tiny disconnected factoids. Maybe I've overstated the case, but the teaching of science in schools is a sore point for many scientists.

Mike W.

(published on 10/22/2007)

Follow-Up #2: towels again

I totally agree about this scienc project my son has to do this for his science fair and its totally stressful. I can not figure out how to make this exciting for my 10 year old.
- Anonymous
I don't think there's any way to make it exciting, but maybe you could make it a little interesting. You could let him know that you will actually decide what brand to buy based on his results. You could compare absorbance/price. You could ask him to figure if the people buying fancy brands are being smart or suckers.

The parade of questions that students relay to us from their classes is depressing. Paper towel absorbancy, tennis ball bounciness vs. temperature,... , not one connects with any exciting idea or important real-life decision.

I'm not sure where these dull questions come from.

Mike W.

ps.  Mike doesn't play tennis,  I do.     LeeH

(published on 04/10/2009)

Follow-up on this answer.