Consumer Testing and the Scientific Method

Learning skills: Students will learn how to use the scientific method to set up an experiment.
Students will identify qualitative versus quantitative observations.
Students will identify variables and difference between independent, dependent, and control.

Vocabulary words: scientific method, absorbency, qualitative, quantitative, independent variable, dependent variable, control, hypothesis, purpose

I use this lab activity at the beginning of the school year to reintroduce the scientific method. I have done this activity in a regular classroom using a demo cart as a station to hold the water in pitchers when no lab area was available. The first part of the activity takes between 15 and 20 minutes. It can be done as a demo, pairs, or in groups. I have done this activity in a large group with my special education class where we went through each step together. If you do both parts plan to take a couple of days and help the students through their frustration trying to write out a procedure.

This lab is easy to set up and uses basic materials. The premise is to determine which brand of paper towel is the most absorbent. The second day if you choose to extend the activity is to have the students then write out a scientific method to test a different component such as strength of paper towel, ability to reuse paper towel etc. My students have come up with several different ideas and ways to do the testing.

Introduction: New! Improved! Brand X performs better than Brand Y. These are claims advertising uses to push their product ahead of another product. Is one product better than another? When a formula is changed is it better, more improved? How can we find out? The scientific method is a process used to test and evaluate. In today's lab we are going to use the scientific method to determine which brand of paper towel is the most absorbent.

Problem: How much water will be soaked up with 1 piece of paper towel?

Hypothesis: If one piece of paper towel is used, then _________________
_________________________________________________________.

Materials: paper towel, stop watch, water, graduated cylinder, tongs, ruler, scissors

Procedure: Part 1
1. Measure and cut out a 6 cm X 6 cm square of paper towel.
2. Place inside the pan.
3. Measure 10 mL of water in the graduated cylinder.
4. Pour the water on top of the paper towel inside the pan.
5. After 60 seconds (1 minute) pick up the paper towel using the tongs.
6. Let the water drip from the paper towel until the drops are 5 seconds apart.
7. Pour the excess water in the pan back into the graduated cylinder. Dry the pan out.
8. Write the amount of water absorbed in the data table (don't forget units).
9. Repeat with the other brands of paper towel.

Data Table

Paper Towel Water absorbed
Brand A
Brand B
Brand C

Questions:

1. What is the independent variable in this experiment
2. What is the dependent variable in this experiment?
3. List 3 controls from the experiment.
4. Did you have any qualitative observations? If so, what were they?
5. Identify one quantitative observation you made in this experiment.


Procedure: part 2
1. Write up a problem/purpose to be tested and show to your teacher.
2. When your teacher approves the purpose write out your hypothesis.
3. Determine your materials and procedure.
4. Teacher accepts materials and procedure.
5. Begin testing following your procedure.
6. Clean up lab area.
7. Write 2 paragraphs indicating what you learned from part 2 and in your own words what the scientific method is.

I always remind the students to dry out the pan in between each paper towel square so the 2nd and 3rd squares are not starting out wet. I have done this lab using three different types of one brand of paper towel which really surprises the students as to which is better. If you are doing this with older students have the cost of each roll and have them use that as part of their analysis. Some students will struggle with writing their procedure give them small prompts and then remind them to use their own procedure not what their neighbor is using. Throughout the school year my students write out several lab procedures and I always refer back to the paper towel lab to help them realize how much they have learned.

I assess my students on their understanding of the parts of the method, the difference between independent and dependent variables, and completion of the data table.
See lab in activity description.

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