Paper
Towels:
How Do
They Stand Up?
Experiments from Team Labs
Experiment Profile
| Connections: | Force,
Elongation (linear measurement), Consumer Science, Technology, Quality Control, Mathematics |
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|---|---|---|
| Skills: | Measuring, Graphing, Analyzing, Inferring, Predicting | |
| Duration: | 1 Class Period with a 1 hour pre-experiment setup | |
| Team Size: | 2-3 students per group | |
| Content Standards: | Science
Standard A (grades 9-12) Science Standard B (grades 9-12) Science Standard E (grades 9-12) Math Standard 1, 4, 5, 11, 13 (grades 9-12) |
Summary
In this experiment you will investigate the nature and construction of one of the most common consumer items purchased and used--the paper towel. As there are many brands and types of paper towels offered for sale, it is likely that there are many similarities as well as differences. This investigation will ask you first to predict qualitatively the "best" and "worst" paper towel from a series of readily available samples based upon thickness, feel, fiber weave, and overall construction. You will also quantify the nature of several material characteristics of the towel. The experimental focus will be on the force and elongation created when paper towel samples are stretched between the Force Probe mounted on a Rotary Motion Probe and a stationary stand. The samples will all be created equal by using the same orientation and a template to trace each to the same size. After collecting all of your data, you will rank each brand based on strength, elongation, and price.
Materials
- Computer
- ThinkStation Interface
- Power Supply
- Communications Cable
- Excelerator 2000 Software
- Force Probe with API (Automatic Probe Identification)
- Rotary Motion Probe 2000 with API (Automatic Probe Identification)
- Paper Clips
- Duct tape or similar
- Nails/pins or similar
Background
Paper towels are one of the most common consumer items purchased. Paper companies have been introducing new fads, names, and marketing schemes for years to get us to buy their paper towel products. We have all been inevitably exposed to many different types of paper towel products. It is a product that is so prevalent and commonly used that ABC's news program 20/20 featured it in one of its Friday night shows recently. Other companies such as Consumer Reports have tested these products extensively.
Packaging
engineers and students have created and tested numerous parameters of
these products as well. It may seem like all paper towels are basically
the same on the surface, but there are some notable differences that after
this investigation may influence your decision to use and/or purchase
specific brands and types of paper towels. It will also make you more
aware of the power and variety of high-use consumer goods and the quality
(or lack thereof) of one of the most commonly bought items.
Procedure
Collecting Data with the Force Probe in Combination with the Rotary Motion Probe
| 1. Prepare your experiment by first purchasing a variety of paper towel brands from your local grocer or supply store. (Make sure you save and note the price of each item and try to purchase similar sized products). | |
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2. Prepare a template that will be used to trace out your paper towel samples to ensure they are all tested in the same manner. Using a piece of cardboard, measure the following parameters and carefully cut out your template: 15 cm long, 3cm wide at both short ends, 1.5 cm wide in the middle, with the 3 cm ends tapering at 45 degree angles at 3 cm in from the ends. The picture at left shows what you are trying to create. |
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3. Place the long edge of your template with the direction of the roll (e.g. the long edge is parallel with the top and bottom of the paper towel roll when in an upright position. This is usually the stronger orientation than across the towel, as the manufacturing process will stretch and orient the longer fibers in this direction when they are produced, making it slightly stronger.) Using a marking pen (a Sharpie-type marker works well), trace around your template on each paper towel product to be tested, being careful not to dig into the towel. Cut along the trace lines with a scissors. Then, wrap each end of each sample with uniform lengths of duct tape. Label
each sample and note its orientation with an arrow. Trace three
samples for each paper towel type, as you will average the three
together for your final analysis. See the following pictures for
our pre-experiment setup: |
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| 4. Next, create a system for holding the sample strips. To do this, we used paper clips, nails, and a little creativity to come up with a secure test setup, as shown in the following pictures: | |
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| 5. Plug in the Force Probe to port A1 and the Rotary Motion Probe to port D1. | |
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6. Launch Excelerator 2000 and click on the Connect&GOTM icon. Excelerator will automatically identify the Force and Rotary Motion Probes and create graphs of Force vs. Time and Angular Position vs. Time. You will need to edit a few parameters before beginning. The software will set default sample rates and durations for the experiment, which you will change in the next step. |
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7.
To change the sample rate and duration of the experiment, click the
Edit Clock icon located on the Excelerator toolbar. |
Show me |
Set the sample rate to 10 samples per second and the duration to 30 seconds. |
| 8. Change the Rotary Motion Probe's measurement type from Angular Position to Linear Position. Add the orange rubber o-ring to the RMP Pulley and make sure you check the appropriate box under the probe's calibration tab. | |
| 9. At this point, make sure the RMP, Force Probe, and paper towel are all hooked together (see photograph below). Zero both probes from within the software and get ready to start recording data. You will need to zero both probes before each trial. | |
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10. Once the probes have been zeroed, you are ready to collect data. Click the GO button, wait a few seconds, then very slowly and steadily pull the RMP/Force Probe apparatus away from the stationary rod to eventually break the paper towel sample. |
View screen |
11. Excelerator will record the Force and Linear Position over time as you pull on and eventually break the sample. Do this three times for each sample. Average the three trials and determine the peak force prior to breaking along with total elongation or stretch noted by the RMP. It may be necessary to click on Rescale in the Tools menu to see all of the data. Save the trial after completing. You should get data similar to the picture at left. |
Analysis of the Data
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You can use the new analysis functions of Excelerator to locate the Peak Force and corresponding Linear Distance in meters moved with the XY Cursor using a right click of your mouse. Click on the trial you are monitoring to have the cursor snap to that trial's data. If you have multiple trials onscreen that are conflicting, go to your View menu tool and uncheck the trials you don't need to see. You can also find the Peak Force and corresponding Linear Distance in the Excel spreadsheet under the worksheet for the trial in question. Average all three trials for both Force and Linear Position for each sample and consider the average the figure you can work with to do the following analysis. (It will be necessary to multiply by -1 as the Forces shown when pulled away from the Force Probe will show up as a negative force and similar for the RMP.) |
| Product | Price | Description | Avg. Force to break | Avg. Distance |
|---|---|---|---|---|
| Bounty | $1.50 | 64 2-ply sheets, 4.9 m2 total | 5.63 N | .012 m |
| Sparkle | $1.55 | 60 2-ply sheets, 5.75 m2 total | 7.89 N | .012 m |
| Seventh Generation (Bleached) | $1.79 | 85 2-ply sheets, 5.2 m2 total | 5.93 N | .009 m |
| Seventh Generation (unbleached, double sized) | $2.99 | 180 2-ply sheets, 11.4 m2 total | 9.61 N | .007 m |
| Hi-Dri | $1.09 | 78 1-ply sheets, 4.9 m2 total | 3.29 N | .006 m |
Rankings:
| A. Ranked by Peak Force shown when stretching the sample to failure is: | |
|---|---|
| 1st = Seventh Generation Unbleached | 9.61 N |
| 2nd = Sparkle | 7.89 N |
| 3rd = Seventh Generation Bleached | 5.93 N |
| 4th = Bounty | 5.63 N |
| 5th = Hi-Dri | 3.29 N |
| B. Ranked by Elongation achieved before failure is: | |
| 1st = Bounty | 0.012 m |
| 1st (tied) = Sparkle | 0.012 m |
| 2nd = Seventh Generation Bleached | 0.009 m |
| 3rd = Seventh Generation Unbleached | 0.007 m |
| 5th = Hi-Dri | 0.006 m |
| C. Ranked by Price, the samples are as follows from most to least expensive*: | |
| Seventh Generation Bleached | $0.34 per m2 |
| Bounty | $0.31 per m2 |
| Sparkle | $0.27 per m2 |
| Seventh Generation Unbleached | $0.26 per m2 |
| Hi-Dri | $0.22 per m2 |
*Divide the cost of each product by the number of square meters in each roll.
Conclusions
In conclusion, do you get what you pay for? Basically speaking, yes. When looking at all these rankings, the stronger, longer stretching paper towels were more expensive. If you need the strongest towel of this bunch for a particular application (perhaps used as a filter or to support some material), in this particular investigation, the Seventh Generation unbleached showed the most force necessary in order to break (being unbleached may also be a nice thing if you were to use it as a filter!). This happens to be a "green" recycled product which showed good performance overall. If you need a cheap towel for the purposes of simple clean-up and hand drying, the Hi-Dri would do the job and cost you less, but it would be inferior in the areas of strength and elongation. The bottom line is the choice of paper towel is up to you, as each towel has varying qualities that would make a better choice depending on the application.
Overall
for the price and observed qualities, the Seventh Generation unbleached
would be a good choice if these were the only 5 towel choices (which they
are not--hopefully you can choose other brands to measure, including that
wonderful brown roll paper we often see in schools that seems very coarse
and thin in comparison), as it held up well in all the rankings. At about
$1.50 per regular size roll, it was equal or even more economical in price
than the others we experimented with, and it has its "green"
qualities as well. The manufacturer of this Seventh Generation product
claims it was made from 100% recycled paper with no chlorine bleaching
and double in size to minimize the packaging per sheet. This uses less
core rolls to manufacture the rolls and packs in more on each truck thus
lowering pollution and fuel consumption--something to think about in our
world of finite resources.
Extensions
Use probeware
to investigate the following:
- Design an experiment using probeware to test the absorbancy of paper towels. Obtain qualitative results in a simple test of dipping a sample of each paper towel into water, to determine which brand best holds water and wicks water up against gravity.
- Test brands that were not observed in this investigation.
- Calculate the costs associated with making and using each type of towel.
- Compare various other paper products such as tissue and toilet paper for similar characteristics.
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About the author... Marc Mueller is the Secondary Curriculum Specialist at Team Labs. His background includes packaging and mechanical engineering, secondary science, technology and vocational instruction. His real-world experience is mirrored in his curricula as he has been focused on engineering, creating applied technology laboratories, and the creation of pre-engineering, computer technology and vocational coursework and activities throughout his career. |
If you have a great experiment idea, please send mail to the webmaster. |
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