Summary

In this lab, students will be introduced to and become familiar with the scientific method. They will apply their understanding by following the steps of the scientific method while investigating the amount of fat in potato chips.

Grade Level

Middle or Elementary School

NGSS Alignment

This lab will help prepare your students to meet the performance expectations in the following standards:

• MS-ETS1-3: Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success.
• Scientific and Engineering Practices:
  • Analyzing and Interpreting Data
  • Planning and Carrying Out Investigations

Objectives

By the end of this lab, students should be able to

• Recognize the importance of the scientific method.
• Create a justified hypothesis based on research and/or prior knowledge.
• Identify variables in a scientific experiment.  
• Carry out procedures and analyze collected data from an experiment in order to make a conclusion.
• Create a controlled experiment, applying the steps of the scientific method.  

Chemistry Topics

This lab supports students’ understanding of

• Scientific Method
• Experimental Design

Time

Teacher Preparation: 45 minutes
Lesson: 1.5-2 hours

Materials

• Graph Paper (12 sheets per group)
• Wax Paper (12 sheets per group)
  • cut to be similar size as graph paper (~8 ½ x 11 inches)
• Four different brands and styles of potato chips, such as:
  • Kettle chips
  • Baked chips (Baked Lays)
  • Pringles
  • Reduced Fat Pringles
• Scale
• Rolling Pin
• Timer

Safety

• Always wear safety goggles when handling chemicals in the lab.
• Students should wash their hands thoroughly before leaving the lab.
• When students complete the lab, instruct them how to clean up their materials and dispose of any chemicals.

Teacher Notes

• I suggest that students work in small groups of 2-3 for this lab experience. 
• In the Materials section, I have given examples of different types and brands of chips that I believe show a wide variety of fat content when doing this experiment. Teachers can choose to use whichever brand/styles that they like. Check the nutrition labels for a reference of fat content.  
• In this lab, we are assuming that the amount of grease observed from each chip is directly related to the fat content of each type of chip. This may not be accurate for every chip, and can be discussed as a potential error in the experiment. I encourage teachers to discuss experimental error possibilities with students.
• This lab can serve as an example to help guide students to complete their own science fair project. 
• The lab is designed so that students can walk through each step of the scientific process and be able to ask questions and gain a deeper understanding about why each step is necessary for the outcome. 
• Note that for the experiment, 4 grams of each chip sample is suggested for each group to use. This is approximately 2-3 pringles, or 4-5 potato chips (but will vary based on size of chips). Students (or teacher) will have to break the chips in order to get each sample of chips to be the same mass. Alternatively, teachers can change the procedure to use a different amount of chips depending on availability and preference.
• It might be helpful for teachers to share some engaging background information with students prior to the lab to encourage a discussion. Explain that like a crime detective, you can use the scientific method to find the answer to everyday problems.
  • Ask students if they have ever done a science experiment on their own. It could be in school or at home. Have students share their stories and experiences.
    
  • After they have shared, show students that they have probably already used the scientific method in real life without knowing it. For example, ask students if they have ever had something that did not work correctly and they tried to fix it. Such as a flashlight, but the light did not work. The first step in the scientific method is that you observed that the light did not work.
    
  • We use the scientific method to solve and answer a problem. The first question we ask when something does not work is, Why doesn't it work?
    
  • Have students come up with some reasons that the flashlight might not work? (Ex: the batteries are drained, the light bulb is broken, the switch isn’t working, etc.)
    
  • Have each student make an educated guess as to why the flashlight does not work—this could be based on some observations. Explain to the students that when you are making your guess, you are creating a hypothesis.
  • How are we going to know whether your hypothesis is right? (We are going to have to test your prediction/hypothesis.)
  • How are we going to test if our prediction is correct?
  • With what you already know about flashlights, you might guess (hypothesize) that the batteries are drained. You say to yourself, if I buy new batteries and replace the old ones in the flashlight, the light should work.
  • To test this prediction, you replace the old batteries with new ones from the store. You click the switch on. Does the flashlight work? If no, have students think of other reasons the flashlight might not work. (Ex: light bulb, wires, switch)
  • Your new prediction is if you replace the broken light bulb, the flashlight will work. It’s time to go back to the store and buy a new light bulb. Now you test this new hypothesis and prediction by replacing the bulb in the flashlight. You flip the switch again. The flashlight lights up.
  • If this were a scientific experiment, you would have recorded the results of your tests and a conclusion for your experiments. The results of only the light bulb hypothesis were confirmed, and we rejected the battery hypothesis based on the evidence. You would also communicate what you learned to others with a published report, article, or scientific paper.