|
This experiment is courtesy of 
|
|
|
Interdisciplinary Approach
to Investigating Popcorn
|
Developers:
|
|
Barbara C. Rosenzweig
Upper Moreland Middle School
Hatboro, PA 19040
|
Dr. Charles Jones
Rohm and Haas Company
Spring House, PA
|
|
Grade
Levels:
|
|
Middle School (5 - 8)
|
|
Disciplines:
|
|
General Science (Life Science and/or
Physical Science), Language Arts, Math, Reading, Social
Studies (These activities may also be used in self-contained
Special Education Classes.)
|
|
Goals:
|
|
To use a model investigation to
introduce and integrate the teaching of the scientific
method into the math, reading, social studies, and language
arts programs.
1. Students will learn and demonstrate
the process of the scientific method of
investigation.
2. Students will use this knowledge in
designing an experiment.
3. Students will use skills in math,
language arts, and reading to design and explain the
experiment.
4. Students may use the format
presented to design experiments to test common household
products.
|
|
Specific
Objectives:
|
|
If you are unable to use the
following investigations in a multidisciplinary setting,
they can be easily adapted for regular classroom
instruction.
- Students will learn proper testing
procedures.
- Students will research the topic
of "Popcorn" in reading class.
- Students will formulate a
hypothesis and test it.
- Students will collect data and
record information in charts and graphs in math
class.
- Students will evaluate the
validity of the results.
- Students will draw a conclusion
based on the results and write it in a coherent fashion
in language arts class.
|
|
Background:
|
|
Why Popcorn Pops
Not only is it the steam trying to
escape that makes popcorn pop, but it is also the special
construction of the pericarp or hull (outer covering), the
amount of moisture in the kernel, and the microscopic
structure of the endosperm ( the starch granules which
expand) that are key to its popping ability. The extra
strong pericarp must be tough enough to seal in the steam
until the pressure is great enough for the kernel to
explode.
|
|
Material:
|
|
Popcorn Experiment
White Popcorn
Yellow Popcorn
Hot Air Poppers
Paper bags for collecting the popped popcorn
|
|
Curriculum
Activities:
|
|
The following sequence of activities
is designed to enhance the understanding of major scientific
testing concepts. For most effective learning, the
activities should be performed in the sequence presented
below.
1.
|
Math Class
This activity
demonstrates the idea that more trials lead to more
accurate or valid results.
Penny Flip
Introduce the idea of
making predictions, determining sample size, and
variations within one set of trials.
Discuss the importance of
controlling as many factors as possible (i.e., the
way the penny is flipped, height, when caught, left
to drop, etc.).
Method: After giving students one penny each,
have them flip them once. For each trial record the
results of how many heads and tails there were.
After about the second or third trial, note the
results. Emphasize what begins to happen as you
accumulate more results. What happens to the
reliability of these results?
|
2.
|
Science Class
Introduce the
students to the idea that they will test a product.
To do this, they will need to know proper testing
procedures. The
General Experiment Outline Guide (following) should
be handed out and the concepts, vocabulary, and
ideas carefully explained. This is in preparation
for the popcorn experiment.
Experiment Outline "Fish"
Game
You may find it
helpful to make up decks of cards which have the
headings and the explanations of the sections of
the outline on them to be used in a game of fish
&emdash; optimally played with two students. Pupils
must ask for the "match" of their cards. For
example, one card "Materials" matches with "the
equipment needed to do the experiment" card. (The
outline can be reproduced on oak tag or any durable
paper and cut apart to make the individual cards. A
class set of 15 decks &endash; for 30 students is
recommended.)
When introducing the
vocabulary of the experimental outline, be sure to
emphasize the difference between the experimental
and controlled variables.
|
3.
|
Math Class
Brainstorm
Introduce the
challenge of testing popcorn. Brainstorm with the
class all of the possible variables that can be investigated. Select the
factor of "kernel color" as the one the class will
test. They may wish to test other variables on
their own or for a science fair project when they
complete the "model" experiment. With the class,
decide on the purpose
or problem
and discuss possible hypotheses or predictions.
|
4.
|
Reading Class
Research
Discuss what the
students already
know and have
observed
about popcorn. Teach students the necessary
research skills not only to find out how popcorn
pops but also to learn about the popping properties
of the various popcorn varieties.
|
5.
|
Social Studies
Research
Students learn about
the history of corn, how it is grown, processed,
used, etc. In the library, students should gather
and record this information and include a
bibliography. Students should then use this
information to help form the hypothesis or prediction.
|
6.
|
Language Arts Class
Write
With the notes that
were gathered in the library during reading and
social studies classes, students should complete a
grammatically correct paragraph explaining how
popcorn pops. They then should use this information
to write the hypothesis for the experiment. Before
doing the experiment in math class, teach proper
outlining procedures (as shown on the General
Experiment Outline Guide) with appropriate margins
maintained, so that they may use this technique in
their experiment write-ups.
|
7.
|
Math Class
Test
Guide the students in
setting up the investigation outline in their
notebooks from the I.
Purpose to the
VII.
Materials section of
the outline. Refer to the Popcorn Experiment
Sample. Next, design
a chart for the experiment (you may wish to use the
blank sample chart). Before the students pop the
corn, teach them how to use the graduated cylinder
and beaker.
After popping the corn, be
sure to review the
results and
discuss what they
mean.
|
8.
|
Language Arts Class
Syntheses
Once data have been
collected and recorded in math class, the language
arts teacher can guide the students in the writing
of their individual conclusions. Questions posed in
the Conclusion section of the General Experiment
Outline Guide should be answered and based directly
on both their collected data as well as their
anectedotal records.
|
* The following pages include a sample
chart and an outline which may be copied and used as student
guides.
|
|
|
|
General Experiment Outline
Guide
I.
|
Title
This should tell what
the experiment is investigating. It is the name of
the experiment and may be in the form of a
question. Be
specific.
|
II.
|
Purpose
Identify the problem
and state it carefully. Why are you doing the
experiment? "To see if...."
|
III.
|
Hypothesis
Before you do the
experiment, what do you predict will happen? This
should be based on Observations and Preliminary
Research."If...,
then..., because..."
|
IV.
|
Experimental
Variable
What is the one condition that you changed? What
are you comparing or testing? You may want to
include a test where you do nothing to your sample
to see what would happen if it were "left alone."
This is called the "Control."
|
V.
|
Controlled Variables
List the things that
you plan to keep the same
during your experiment, so that they will not
affect your results. These are the conditions that
you do not
want to test at this
time to make your testing fair.
(List at least 6.)
|
VI.
|
Procedure
List in a
step by
step way how to do
the experiment. If you do a good job, someone
reading your procedure will be able to repeat it
accurately. You should include at least
TEN trials or samples. Try to do your
tests in a random (changing) order. Analyze results
and discard any that show a major error.
|
VII.
|
Materials
List the equipment
you need to do the experiment. Be specific; list
the kinds and amounts.
|
VIII.
|
Results (Observations)
Use charts and graphs
to record your data. All calculations should be
clearly labeled. Be sure to keep a journal of all
information gathered while doing your
investigation.
|
IX.
|
Conclusion
A. What was proved?
Analyze what your results meant. What were the
differences between the factors or products you
tested? Check the ingredients or makeup of your
variable. (Be careful not to confuse close results
with a major difference. Is it close enough to be
considered of "no significant difference" due to
possible experimental error?
B. What conditions may have
affected your results causing an experimental
error?
C. How would you change the
design of the experiment to eliminate the problems
and make it a better test?
D. What were some of the
conditions that were impossible to control?
E. What did you learn from
your experiment that you did not expect?
F. If your results are
accurate, what recommendations would you make as a
result of your experiment?
|
The following explanation can be
used for teaching the concept of "controls" from the
Experiment Guide. If you were testing to find out which
fertilizer makes petunia plants grow taller, it would be
important to know what would happen if one of your plant
sets has no
fertilizer added. Then
you could compare the results to those of the fertilized
plants. The set with plain water and no fertilizer would be
considered your control set.
*
Popcorn Experiment
Sample:
For this classroom experiment, each
group of students should pop a portion of the 10 trials,
testing at least one sample of yellow and white corn and
placing its data on the class chart.
I.
|
Title
Will yellow corn
kernels pop more than white?
|
II.
|
Purpose
To see if the color
of the corn kernel (white or yellow) affects the
amount of popped popcorn kernels.
Before formulating the
hypothesis, students should record their
observations of each sample of 100 unpopped
kernels; note weight (mass), size and shape
variations, etc. to help make the
hypothesis.
|
III.
|
Hypothesis
If both yellow and
white varieties of corn are popped, then I predict
that a higher percentage of white will pop than
yellow, because the white ones are larger on
average than the yellow ones.
|
IV.
|
Experimental
Variable
The color of the corn (white and yellow)
|
V.
|
Controlled Variables
A. Same number of
kernels tested for each trial
B. Same popping procedure
C. Same brand of popcorn
D. Both sets of colored kernels are without salt or
butter
E. Kernels are kept at the same temperature and
humidity
F. Same time popcorn popped
G. Same temperature at which popcorn is
popped
|
VI.
|
Procedure
A. Prepare the two
samples of kernels by counting out 100 of each type
of popcorn and recording the approximate volume of
each in a graduated cylinder.
B. Pop the first sample using
a hot-air popper for 2 minutes.
C. Collect all of the popcorn
flakes and unpopped kernels. (You may need to turn
the popper upside down to get them all out.)
D. Record the volume of the
flakes in a graduated cylinder or beaker.
E. Repeat for a total of 10
trials.
Since this will be done in
the classroom (electric outlets are necessary), you
can have as many groups testing as you wish,
depending on the amount of available time and hot
air poppers (preferably 4 or more for a class of
28). Caution:
Be careful not to overload outlets. Know where the
circuit breakers are before you
begin.
|
VII.
|
Materials
A.
|
Yellow and white
popcorn kernels
|
B.
|
Hot air
poppers
|
C.
|
Paper bags for
collecting the flakes and unpopped
kernels
|
D.
|
Metric ruler
|
E.
|
Graduated cylinder
(for finding the volume of the
kernels)
|
F.
|
600-mL beaker (for
finding the volume of the flakes)
|
G.
|
Triple beam
balance
|
|
VIII.
|
Results (Observations)
Here students
develop a chart for recording the collected data. A
large class chart should be made to reflect at
least 10 trials so that an average may be taken.
They should also keep a record of everything
observed as anecdotal information to help in
reaching their conclusions.
|
IX.
|
Conclusion
A. What was proved?
Analyze what your results meant. What were the
differences between the factors or products you
tested? Check the ingredients or makeup of your
variable. (Be careful not to confuse close results
with a major difference. Is it close enough to be
considered of "no significant difference" due to
possible experimental error?
B. What conditions may have
affected your results causing an experimental
error?
C. How would you change the
design of the experiment to eliminate the problems
and make it a better test?
D. What were some of the
conditions that were impossible to control?
E. What did you learn from
your experiment that you did not expect?
F. If your results are
accurate, what recommendations would you make as a
result of your experiment?
|
Comparing the Volume of White and
Yellow Popcorn
|
White Corn
|
Yellow Corn
|
Trials
|
# Popped
Flakes
|
Volume of
Flakes
|
# Popped
Flakes
|
Volume of
Flakes
|
1
|
|
|
|
|
2
|
|
|
|
|
3
|
|
|
|
|
4
|
|
|
|
|
5
|
|
|
|
|
6
|
|
|
|
|
7
|
|
|
|
|
8
|
|
|
|
|
9
|
|
|
|
|
10
|
|
|
|
|
Total
|
|
|
|
|
Average
|
|
|
|
|
Journal:
|
|
Sample
Results:
|
|
Yellow Corn
Trials
|
Mass in grams
|
Size
range
(in cm)
|
Volume
(in grad.
cyl.)
|
#
Unpopped
Kernels
|
#
Popped
Flakes
|
Volume of
Popped
Flakes
|
1
|
11.45
|
.6 - 1.0
|
14cc
|
12 (1.12g)
|
88 (9.13g)
|
375cc
|
2
|
11.78
|
.7 - .8
|
14cc
|
19 (1.85g)
|
81 (8.60g)
|
310cc
|
3
|
11.48
|
.6 - .8
|
14cc
|
16 (1.57g)
|
84 (8.70g)
|
310cc
|
White Corn
Trials
|
Mass in grams
|
Size
range
(in cm)
|
Volume
(in grad.
cyl.)
|
#
Unpopped
Kernels
|
#
Popped
Flakes
|
Volume of
Popped
Flakes
|
1
|
11.57
|
.6 - .9
|
14cc
|
23 (2.38g)
|
77 (8.01g)
|
350cc
|
2
|
11.86
|
.4 - 1.1
|
15cc
|
20 (2.01g)
|
80 (8.58g)
|
400cc
|
3
|
12.00
|
.6 - .9
|
15cc
|
23 (2.38g)
|
76 (8.50g)
|
350cc
|
Additional questions for
consideration:
- If there is a difference between
the initial mass of the corn and the popped corn, what
happened to account for this change?
- How much variability is there in
the samples of each kind of corn? Why do you think this
is true?
- What happens to the reliability of
the results as the sample size is increased?
- What practical problems are there
in the unpopped kernels and the popped corn? How can you
limit these?
|
|
Special
Note:
|
|
Although comparing results in
microwave ovens to those in hot air poppers may sound like a
good idea, there are a lot of practical considerations that
may make it prohibitive. The factors of "time" and
"temperature" are difficult to control for the small sample
size of 100 kernels. Since a microwave may be used to make
popcorn, it is suggested that prior to the students'
investigation, the teacher should determine the correct
power level and time needed.
|
|
Suggested
Extensions:
|
|
Other variables can be tested, such as
kernel size, flake size, volume, profitability (comparing
the ratio of the volume of flakes to the weight of the
kernels), using the same outline form. Since the main
purpose of these activities is to provide students with a
model for controlled scientific investigation, students
should be encouraged to test many of the household products
they use.
|
|
References:
|
|
Education Division of the American
Chemical Society, Ideas in
Science, "Popping Corn"
Science Resources for Schools, American Association for the Advancement of
Science, Vol.3 No.3,
1986.
Eldredge, J.C. and Thomas, W. I.,
Popcorn - Its Production,
Processing and Utilization,
Iowa State University of Science and Technology, Bulletin
P127, Ames, Iowa. July 1959
Hoseney, R.C., Zeleznak, K., and
Abdelrahman, A., "Mechanism of Popcorn Popping",
Journal of Cereal
Science, Vol. N.1, Academic
Press Inc. London, 1983.
Sibley, Lynn K., "Popcorn",
Chem Matters, American Chemical Society, Washington, D.C.,
October 1984.
|
This experiment is courtesy of 
|
|