For an example of what a product test experiment might look like, we designed one in class last week. All the students participated in the experiment. We wanted to know if a local artist’s claim that Staedtler erasers are the best was in fact a scientifically true statement, or just her preference.
Students, pay careful attention to how in this example we have tried to explain in as much detail as possible all the parts of our experiment outlined in your template. You don’t have to use the template to write up your report, but it is a helpful guide. Click here for sample template
The Staedtler brand eraser will not require less time or effort than other erasers. The Staedtler eraser will not be a higher quality eraser than others because the materials are similar between all of the erasers. Two of the erasers are made of vinyl. The other two are made of synthetic rubber. Synthetic rubber is cheaper and will erase just as well as vinyl.
How will I collect data for observation?
Eight different study groups will participate in the experiment. One person from each group will do all the erasing to maintain control over the experiment. The other people will observe and fill out a questionnaire about their observations. They will record observations on the effort required, damage to the paper, time required to fully erase, and the amount of wear caused to the eraser judging from the shavings.
Here’s an introduction to our experiment.
- HB pencil
- Erasers (4 different kinds)
- Test sheet with shading circles
(1) Set up experiment by creating testing sheets on same kind of paper. Shade in each circle with identical pressure and time (30 seconds). Double check to ensure that all 4 circles are equally shaded.
(2) Create testing groups. The same person should do all the erasing for each of the four erasers. At least two others observe and record time it takes to completely erase the pencil shading.
(3) Individually test each brand of eraser. Limit erasing time to 60 seconds. Make sure there are enough groups to get a good sample of how well each eraser works on average. After each eraser is tested, the observers should discuss and record observations on the questionnaire using a Likert scale (1-5) judging the effort required, wear caused on paper, wear caused to eraser, and time required to completely erase the pencil shading. (What is a Likert scale and what is it used for? )
(4) When all four have been tested, closely examine the testing paper to rate from 1-4 (best-worst) how well each eraser erased the pencil shading. Keep the testing papers as evidence and calculate an average of results from the testing paper and the questionnaire.
RESULTS & OBSERVATIONS:
All groups reported some differences in the performance between the four different brands:
- Eraser #1: Ticonderoga pencil eraser (synthetic rubber)
- Eraser #2: Pink Pearl eraser (synthetic rubber)
- Eraser #3: Staples white eraser (vinyl)
- Eraser #4: Staedtler eraser (vinyl)
We noticed that the erasers performed most differently in the amount of time and effort required to completely erase the HB pencil shading. The vinyl erasers required less time and effort, while the pink synthetic rubber erasers required more. However the pencil eraser caused less damage to the paper than the other three. This is likely because it was smaller. The Staples eraser (#3) was effective at erasing but caused far more wear and tear to the eraser meaning that it will wear out very quickly and leaves a lot of shavings behind which made quite a mess. The Staples eraser also did not perform any better in overall erasing than the cheap, simple eraser on the end of the Ticonderoga pencil. The best performing eraser was the Staedtler eraser, while the worst by far was the Pink Pearl eraser.
Each observation group that participated filled out a questionnaire to record their evaluation of each eraser. QUESTIONNAIRE DATA COLLECTION
The results were compiled onto these simple charts using Google Sheets. I then used the function =AVERAGE( ) to find the median result between each group. This way I could know what the most common result of the eight different tests was.
As you can see from the photos below, the observation groups also evaluated and ranked which erasers were most effective at completely erasing the marks on the testing strips. That information was also compiled into a table and averaged.
Finally, Google Sheets has a neat function that creates simple charts to help you visualize and communicate your data more effectively. Good science requires that we communicate our complex data in more visual and convincing ways.
Explain the results. Use scientific terms and language. Compare your results to the original hypothesis – were you correct? Why? What implications or applications does this have for everyday life?
Overall, my initial hypothesis proved wrong. I predicted there would not be a substantial difference between the erasers but in fact there was. However, the difference in performance cannot be solely blamed on the materials the erasers are made from because the performance of the pencil eraser and the Staples eraser was very similar. In some cases, such as wear and damage to the paper, the synthetic rubber eraser outperformed the vinyl eraser. But in nearly all categories, the Staedtler eraser did prove to be a much better performing product, especially at doing what erasers should do: completely erasing pencil marks and shading. So the difference must be attributed to the quality of the product itself and the quality of vinyl used in its manufacturing, not simply what the kind of material the product is made from.
So when considering the purchase of erasers for fine drawing, sketching or other pieces of work that will be shared and presented, the Staedtler eraser is recommended over other common brands. However, it should also be considered that a good quality pencil will produce a reliable performance for smaller pieces of work, and the additional cost of another eraser may not be necessary. Consumers should be aware that simply because the eraser is made from vinyl, not all vinyl erasers will perform as well as a Staedtler eraser.
This experiment should be considered a fair test for a variety of reasons. For starters, there were numerous controls on potential variables. Only one student could perform all of the erasing, and the other students were observers to maintain some consistency and to insure that the only change made was the eraser (independent variable) being used. The fact that there was very consistent results that did not vary much also shows that this experiment controlled many of the potential problems that would have made the data invalid. Finally, during preparation careful attention was paid to maintaining consistency between all 8 testing sheets. The observations and data collected can only be attributed to the difference in performance between erasers, not other factors.
One way to improve this experiment might be to expand the number of test groups so we could get even more accurate averages from a wider range of people.