Popcorn Neutrino Lab

Purpose:

To develop an experimental model of the beta decay in which the unpopped kernel represents the nucleus prior to the decay. The popped kernel represents the decayed nucleus. The law of conservation of mass states, the sum of the mass of the particles after decay should equal the mass of the initial particles before decay. In beta decay this was found to not be the case. In this experiment will attempt to determine if the law of conservation of mass holds for this model. Like the beta decay, there is a change in mass and energy as the popcorn pops. Depending on the popcorn popped the mass will vary. Three outcomes that this model can demonstrate are. To have the students identify the amount of mass loss. Second to compare the mass loss from one type of popcorn to another. And to identify what particle represents the lost mass in this model and to determine a way to confirm their hypothesis experimentally.

Connection to Curriculum/Teacher Preparation for Activity:
Standards:
NSES/Benchmark Standard: Physical Science Content Standard B
Minnesota State Standards: Middle Level: Physical Systems #1,2
Part(s) B2, C of the High Standards Below
Concepts in Chemistry, Concepts in Physics
Materials List:
Hot Plates Popcorn (several brands) Containers for popcorn
Hot Air Poppers Balances Gloves
600 or 1000 ml beakers Oil (optional)
Lab Time: 1 class period (50 min.)
Teacher Preparation/Suggestions:
1. Introduce challenges by steaming or heating the popcorn before-hand.
2. Use several types of popcorn and analyze differences.
a. old vs. new b. white vs. yellow c. generic vs. brandname
(for higher level students)
1. Have students devise a way to prove conservation of energy-using the height a kernel pops.
2. Relate to Pauli's work on beta decay.
3. Statistical interpretation of the results.
4. Analogy to formation of neutrinos

Teaching Sequence:

1. The Law of conservation of mass (Review)
2. An Introduction of nuclear particles
a. Proton
b. Neutron
c. Electron
d. Neutrino
e. Anti-Particles
3. An introduction of nuclear decay
a. Types
b. particles formed
4. Pre-Lab
a. Students Identify Types of Nuclear Decays
b. Students Write Types of Nuclear Decays
5. Lab Popcorn Neutrinos
a. Method I "Hot Air Popper"
b. Method II "Beaker and Oil" (Optional)
c. Method III "Beaker" (Optional)
6. Post Lab
a. Summarize individual group results
b. Combine group results into a classroom result (Optional)

Student Assessment:

Explanation:

Teacher notes and background information:
Law of conservation of mass: mass of reactants = mass of products

Average percent composition for water in a popcorn kernel: 11-15%

Energy (heat) must be inputted to have a phase change for the water

Exchange:

As part of the student's lab report they would be required to include a table of the mass lost per kernel for the different types of popcorn. To facilitate the different speeds with which the groups would finish, a transparency would be placed on the overhead where the student's would record their percent water composition.

When all groups were finished a discussion would take place. Among questions that could be discussed are: "Why was the mass per kernel of the original kernel not the same as for the popped kernels? What was the product that was lost during the popping of the popcorn? Is there a way that the experiment can be improved to a capture the lost mass?

After the discussion, students would be instructed on the proper way of writing a lab report. This could possibly be integrated into an English class as many English classes do discuss writing a lab report in either the ninth or tenth grade. A rubric would be given to the students prior to their writing of a lab report as a guide to how they would be graded.

Evaluation:

Rubric:

Are your name, date and title on the lab report? 1 pt

Purpose: Is the purpose of the lab explicitly state in the first paragraph or sentence? 1 pt 2 pts 3pts

Procedure: Is the procedure that your group followed listed in the proper form? 1 pt 2 pts 3 pts

Results/Data: Are the results from each group included in your table or graph? 1 pt 2 pts 3 pts

Analysis/ Conclusion: Were you able to draw conclusions from the data in the tables? (Hint: describe the results that each group got and relate them to the law of conservation of mass). 1 pt 2 pts 3 pts 4 pts 5 pts

Discussion: Did you answer the discussion questions that were listed on the board? (1 point per question)
1 pt 2 pts 3 pts 4 pts 5 pts

Classroom Components:

Background: This is a re-do of a relatively easy lab investigation using popcorn and the relationship that exists between the percentage content by mass water and the kernel's popping success; the idea moisture content range for popping falls between 11 and 16%. Teachers can vary the results of this experiment by altering the water content of their popcorn via storage of seed where it can gain moisture e.g. damp areas, moist paper toweling or drying the corn in an oven or desiccator. The variation above or below this range will either cause the corn to rot if there is too much water or not to pop if there is too little water.

The point that needs to be stressed the most from a safety standpoint is whether the students will consume the popcorn e.g. if conducted in the lab do not use standard lab glassware to collect, mass and handle the corn for fear of chemical residues and giving students a feeling that is it fine to eat from this glassware.

Resources and references: N/A

General Activity Description: See Popcorn Lab Handout included

Analysis:
1. List the average percentage of water by mass for each of the four types of popcorn used.
2. Which brand of popcorn had the fewest unpopped kernels?
3. Which brand of popcorn do you believe is the most expensive? Explain your answer.
4. How might the success of popping be varied? What things could have affected the success of popping?
5. How do you think microwave popcorn may differ from the brands used in our lab?