This post is part of the DIY Summer Camp Activities series. Find more fun things for kids of all ages there.
I coach a homeschool Science Olympiad team and one of the events is Experimental Design. For the event, students use various provided materials to design and conduct an experiment on a specific topic.
For one of our practice sessions last year, I gave them different brands of paper towel and asked them to conduct an experiment on absorbency.
The result – for me – was that I changed my brand of paper towel!! Yes, the results were that dramatic.
So the DIY summer camp activity will not only be educational and fun for your children but should also be beneficial for you!
Here is a step by step walkthrough of the experiment. You can use more water and more paper towels if you are using a bigger glass. Just adapt to make it work with the equipment you are using.
Hypothesis
Get your children to come up with a hypothesis as to what they expect to happen and why eg. We believe brand A will be the most absorbent, brand B then next absorbent and brand C the least absorbent because …..
Materials needed
- 3 (or more) different brands of paper towels (Note how much they cost)
- graduated cylinder (if you don’t have one use a skinny glass and measure the water you pour in and what is left using a measuring jug)
- tap water
- aluminum pie dish or a tray to prevent a mess 🙂
Procedure
1. Gather needed materials
2. Lay all paper towels on top of each other and use scissors to trim so they are all the same size (this way you’re testing how the absorbency of the towels differs and size isn’t a variable). You will need 3 pieces of each brand.
3. Take 1 paper towel from brand A and roll lengthwise so its diameter can fit in the graduated cylinder
4. Fill the graduated cylinder with lukewarm tap water to a volume of 30ml. (Note: we use metric measurements as that is standard in the scientific community).
5. Put a rolled paper towel in the cylinder so 3cm of the towel is submerged in the water
6. Hold the towel in water for 10 seconds, then lift it up out of the cylinder and allow to drip into the cylinder for 5 seconds. (The purpose for doing this was to make sure the test showed what the paper towels were absorbing AND keeping in. After all, you don’t want towels that drip out everything you’ve just cleaned up!)
7. Either dispose of paper towel in a waste bin OR place in pie pan and throw them all away at once when you finish
8. Record the volume of water remaining in the cylinder and subtract from the original 30ml to see how much water the towel absorbed
9. Repeat steps 3-8 two more times with the same brand of paper towel.
10. Now take the next brand of paper towel and do steps 3 – 9.
Data Table
Record your data as you do the experiment. Once you are finished, calculate the average amount of water left for the 3 trials of each brand of paper towel.
Graph
Draw a bar graph of the average of the tests for each brand of paper towel. It will look something like this:
The independent variable in this experiment is the brand of paper towel i.e. it is the one the tester is changing. The independent variable is always on the X-axis.
The average amount of water (over the 3 trials) left in the cylinder is the dependent variable and the bar should be drawn to this height.
Conclusion
Now that you have the data, and the graph, students can reach a conclusion. They need to decide if their hypothesis was supported by the data or not (NOTE: scientists never say their hypothesis was ‘true’ or ‘false’ but only whether the result of their experiment supported the hypothesis or not)
The Science Behind It
Paper towel is made of plant fibers. Capillary action in the fibers draws the water into the paper towels. If you have a microscope, put a piece of paper towel under it for your children to look at. The fibers are made up of tiny linked sugar molecules called cellulose. Cellulose attracts water. If you look at paper towel under a microscope you will also see that there are spaces between the fibers – and those will hold water too.
To take this one step further, take a look at how much each roll of paper towel cost and try to calculate the cost of one “test strip” for each. Relate the cost to how absorbent the brand was and that should help you select what to buy in the future.
And your children can see a practical use for science!
Don’t forget to take a look at other DIY Summer Camp ideas to do with your children.
Meryl van der Merwe
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