Experimental Design: The Popcorn Experiment

Purpose:

For students to better understand how to approach a problem scientifically. For this purpose students will develop a good testable question and hypothesis, design and conduct a good scientific experiment, and report findings to an audience, using popcorn as an experimental model.

Objectives:
Students will be able to:
• Design an experiment to test a hypothesis.
• Write an easy to follow procedure step by step for their experiment.
• Conduct an experiment collecting appropriate data using a data table.
• Analyze and interpret data with an appropriate graph and conclusion.
• Communicate experimental findings in the form of a group presentation.

Grade Level:
This lab was specifically designed for 10-12 grade chemistry. However, could be easily adapted for any middle school or high school science classroom.

Prior Knowledge:
This activity is used at the very beginning of the year, and is designed to explore what students already know about variables in an experiment and their experience making a data table and graph. It is the foundation for designing experiments throughout the year.

Time Required:
This lesson was designed to fit 5 blocks of 80 minutes. It can be adapted for more or less time if necessary.

Including All Students:
This activity was written to include tactile, visual, auditory, and written activities so that all students would be engaged. There are background topics, including the history of popcorn, incorporating cultural backgrounds in the lesson. This activity can be adapted for all students and has the flexibility to be adapted for any classroom setting.

Questions to Ask Along the Way:
1. Is your hypothesis testable? Does it include one independent variable and one dependent variable?
2. What is your independent variable and how will you change (vary) it?
3. What is your dependent variable and how will you measure it?
4. What other variables might affect your results? How will you make sure they do not?
5. Is your procedure clearly explained step by step so someone else could repeat your experiment?
6. What does your data mean? Does your data support your hypothesis? How do you know?
7. On a scale of 1-10, rate the accuracy of your measurements (10 being perfect, no error). What specific things in your experiment could have contributed to error? Is there a better way to make your measurements? What other factors could you change to make your measurements more accurate next time?
8. What further questions/hypotheses could be tested?


Pedagogy Used:

• Active learning/discovery learning
• Cooperative learning/small group instruction
• Hands-on learning
• Inquiry-based learning
• Student-centered instruction
• Computer-assisted learning
• Data analysis, collection, interpretation
• Laboratory experiment
• Authentic and Alternative Assessment
• Self-evaluation

National Science Education Standards Addressed:
Grades 9-12
Science as Inquiry:
1 Abilities necessary to do scientific inquiry
1 Understandings about scientific inquiry

Science and Technology:
1 Abilities of technological design
1 Understanding about science and technology


Missouri Science Education Standards Addressed:

Strand 7: Inquiry, 1A-E, grades 9-11
Strand 8: Impact of Science, Technology, and Human Activity, 1C, grades 9-11

Materials: (will vary by what students decide to test)

Popcorn Poppers: air, oil, microwave, others
Oil for oil poppers: canola, vegetable, corn, and olive, coconut
Popcorn kernels: white, yellow, red, blue; several different brands
Bowls or bags to catch popcorn
Stopwatches
Digital cameras or video recorders
Rulers or meter sticks
Measuring cups to measure volume
Safety glasses
Food coloring
Flavors of Kool-Aid

Safety:
A few safety issues should be discussed. Remind students that normally there is no food or drink in the lab, however, this lab is a food lab, in which they will be able to eat. Remind students where to find safety equipment such as fire blanket and fire extinguisher, and how to use them in case of a fire. Also remind students to be careful not to get water on any of the poppers. Depending on the nature of the designed experiment students make need to take safety precautions unplug poppers when not in use and not and wear safety glasses, especially working with the oil poppers. It is necessary to discuss normal use with the poppers. Students are told that no oil is to be used in the air poppers and no poppers should be washed, only wiped with paper towels. Students are cautioned about splattering oil and touching hot surfaces and making sure poppers are unplugged before handling.



Preparation and Procedure:
Before this lesson, class time should be spent making sure students are familiar with independent variables, dependent variables, controlled variables, and hypotheses.

Day 1: Scientific Method and Developing a Testable Question
• KWL activity generating what they know about the Scientific Method, what they want to know, generating some questions they might want to investigate.

• Making POPCORN! Discovery Activity. It is necessary to give some general instructions on the various poppers since many students will not have seen them before. Remind students to not put oil in the air poppers and not to wash any of the poppers. They also need to know appropriate portions: ¼ cup of kernels per popper and 1 tablespoon of oil with oil poppers. Students will make popcorn writing down step-by-step procedure, materials needed, making a list of what is need to make popcorn, and try to explain how popcorn pops. This activity should be followed up with a discussion of the importance of well-written procedures. It would be helpful to read a few of their procedures and follow them word for word in front of the class to help see if their procedures are thorough. Also, if time allows, have the students brainstorm possible independent variables and dependent variables that could be explored when designing their own experiment. It would also helpful to discuss as a class what variables cannot varied during the experiment, such as the temperature of the popper.

• Internet Treasure Hunt: As a homework assignment, students will look up 4 websites about the scientific method, tell what they have learned and answer questions about the website.

Day 2: Designing an Experiment with Popcorn

• Internet Treasure Hunt: At the beginning of class, students will be divided into lab groups of 3-4 students. Each lab group will have 2 Internet sites to visit and answer questions regarding that website and what they have learned about their topic (history of popcorn, nutrition of popcorn, genetically engineered foods, etc.) More topics can be added or multiple groups can be assigned the same topic.

• Each lab group will then generate a testable question and hypothesis to be approved by teacher on something they would like to test about popcorn. Remind students of the importance of having one independent variable, one dependent variable, and controlled variables. They will spend time in that class period filling out an experimental design sheet, identifying variables, materials necessary, and their procedure. Each lab group must turn in a copy by the end of class so that the teacher can approve the experiment and have necessary materials ready for the next class period. They also should make a data table and be ready to perform their experiment the following class period, knowing each person’s role in conducting the experiment.

Possible Ideas to Test: (It is helpful to brainstorm ideas as a class after Discovery Activity)

Independent Variables Dependent Variables
Type of popper Time of first pop
Brand of popcorn Time of last pop
Color of kernels Number of kernels popped
Type of oil Percentage of kernels popped
Amount of oil Height of pop
Amount of kernels Amount of oil in piece of popcorn
Time in popper Volume of popcorn popped
Flavor of kernels (soaked) Number of unpopped kernels
Time soaked in water Number of burnt kernels
Pressure in popper Loudness of pop
Age of kernels (dryness) Size of popped kernels



Day 3: Conducting the Experiment
• Student-Centered Experiment: Students will come to class prepared to begin their popcorn experiment. Students are reminded of safety concerns, to ask teacher when they have questions, and to work efficiently. They must collect all of their data during this class period. They also are responsible to clean up after themselves. While students conduct their experiment, the teacher needs to move around making sure each lab group stays on track and has the materials they need. The teacher needs to help monitor the time and even adjust the number of trials that can be completed during the period. Ideally, each lab group conducts 9 trials, but it can be cut to 6 if time becomes an issue. They also need to finish early enough for cleaning up and quick review of data tables and graphs.

• Each lab group will need to document their procedure with a video camera. They will need to video about 1 minute of their procedure that will be included in their group presentation.

• At the end of the class, a quick review of setting up a data table and graphing basics are necessary. Each student should come to class the next day with a good data table and graph.

Day 4: Work on PowerPoint Presentations
• Authentic Assessment: Students will present findings in a PowerPoint presentation, including an appropriate data table and graph. They will also present ways they could improve their experiment and further testable questions. They will be given the grading rubric and told that they will fill out a self-evaluation of their own presentations and that the teacher will also evaluate. They will also have to include their Internet research on popcorn (history, nutrition, genetically engineered corn).

• They will need to work efficiently during class time to have their presentation ready for the following class and if they are not finished, they will have to work outside of class to be ready to present the next class period. Ideally, students can work on computers in the classroom or in a computer lab during this class period.

• Their presentations should be 5-7 minutes, everyone should equally participate, and it must include a video clip of their procedure.

Day 5: Presentations
• Students will come to class ready to present lab findings with their lab group. After they present, they will turn in a copy of their presentation for teacher evaluation, and they will turn in their self-evaluations.

• Finish KWL on the Scientific Method and discussed what was learned by the process they went through.

• Teacher Reflection: After presentations, teacher will make sure that the presentations accomplished the objectives for the lesson and address any further content concerns (i.e., graphs, data tables, interpreting data). Teacher will also self-reflect making sure this lesson covered the 6 stars of science format, and make note of changes or adaptations for next year.

Where to Go From Here:
If more time allows, it would possible for students to develop another testable question and conduct another experiment or revise their own and repeat for more data. Students could also have some practice reading experiment scenarios and identifying independent and dependent variables, discussing how they would set up an appropriate testable experiment. It would also be a benefit to invite a scientist to discuss how they develop a hypothesis, conduct and experiment, and interpret results.

Suggestions for Assessment:
Students can work in groups to produce a Power Point Presentation, a poster, or an individual lab report.


**I have adapted this from The Popcorn Experiement that I developed through a parternship with the Frontiers in Physiology Program wtih the American Physiology Society.
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