NAME: ________________________
Date: ______________________
POPCORN/ Bunsen burner LAB
Objectives: This lab is designed to review qualitative and quantitative
observations and it is also a review of the Law of Conservation of Mass and Energy as well
as to practice lab safety and the use of a Bunsen burner.
PRE-LAB QUESTIONS:
1. Define Conservation of mass and energy?
2. Define Quantitative Data and Qualitative Data.
3. What safety precautions are needed for this lab?
4. What equipment will you use to measure the mass of the popcorn?
BACKGROUND INFO:
According to The Popcorn Board, Americans today consume 17 billion quarts of popped
popcorn each year. The average American eats about 54 quarts.
No one knows the exact origin of popcorn, but the oldest ears of popcorn ever found were
discovered in a Bat Cave of west central New Mexico in 1948 and 1950. Different reports put the
range of age of the popcorn to over 4,000 to over 5,600 years old.
Popcorn pops because of the natural moisture contained inside the kernel. When the
internal water temperature reaches 100C the kernel expands rapidly and the liquid water is
transformed into gas, which takes up much more space. But even popcorn, with its special hull,
doesn’t always pop. Popcorn must have two important properties to pop well. First, the amount of
moisture in the kernel must be very close to 13.5%. Too little moisture and enough steam won’t
build up to pop the kernel. Too much moisture and the kernels pop into dense spheres, rather than
the light fluffy stuff popcorn fanciers love. Second, the kernels must not be cracked or damaged
in any way. Even a small crack will let steam escape, keeping the necessary pressure from
building. Popcorn kernels with the right amount of moisture and unblemished hulls pop into the
snack that just about everyone enjoys.
Procedure:
1) Identify your 4 best kernels of fresh popcorn. Handle the kernels with clean tweezers to
avoid moisture on the hands from being transferred to them.
2) List two qualitative observations about the kernels. Record answers in the chart provided.
3) Measure the length of the 4 kernels (in centimeters) and record in the chart.
4) Find the mass of the 4 kernels (all together) using the lab scales. Be sure to use the plastic
weighing dish. Record this total mass (including the mass of the plastic weighing dish).
NAME: ________________________
Date: ______________________
5) Ignite the Bunsen burner and adjust for a hot, blue in blue flame.
6) Place ONE kernel at a time in the ceramic bowl using tweezers. Hold the ceramic bowl
with a clamp and with continual shaking of the clamp, pop the kernel. Place all the resultant
parts in the plastic weighing dish.
7) Record all observations made while the kernel was getting ready to pop.
8) Pop the rest of the kernels, placing all parts in the plastic weighing dish. Measure the mass
of all the popcorn “flowers”, parts and the plastic weighing dish. Record the mass in the
chart.
9) Throw all the popcorn parts and the plastic weighing dish in the trash can.
Qualitative
Description
BEFORE
kernels are
popped
Quantitative:
Length of
kernel
(cm)
Quantitative:
Mass of the 4
kernels
Before
Popping
Quantitative:
Mass of the 4
Kernels
After
Popping
XXXXXXXX
XXXXXXXX
XXXXXXXX
Qualitative
Description
AFTER kernels
are popped
Kernel #1
Kernel #2
Kernel #3
Kernel #4
Averages
Draw a labeled diagram that demonstrates the step by step changes that occur
during the popping of the popcorn kernel and the forces that cause this explosion.
Post Lab Questions: Use complete sentences and correct units for full credit.
1.
How does heating the popcorn kernel affect the pressure inside the popcorn?
NAME: ________________________
Date: ______________________
2. For each kernel calculate the mass lost, the fraction of the original mass of each kernel
lost on heating, and then the percent of the mass lost by each kernel.
Average Mass of un-popped kernels ________________grams
(From Data Chart)
Average Mass of popped kernels ________________grams
(From Data Chart)
Mass difference
________________ grams
(Subtract Before from After Kernels)
Formula to Use To Determine Percent of Mass lost: Show all calculations
% of Mass loss
=
Mass Lost________ X 100
= ______________
Mass before popping
3.
Did the Kernels follow the Law of Conservation of Mass and Energy? __________
Explain your answer and describe why this happened? Show qualitative and quantitative
data to back up your answer. (Use your data table)
4. Explain the phase changes that occurred during the popping of the kernel. Draw a
labeled diagram of those changes as well. (Phase changes include solid, liquid, gas)
5. Name the Independent and Dependent Variables of this lab. What would be the control?
6. Since a kernel contains 61% starch, what type of organic macromolecule is found in
popcorn? ____________________________
7. Why is corn not 100% digestable for humans? Why can cows digest corn?
8. Use your lab report template/ rubric to complete the Analysis and Conclusion.