In an effort to clarify instructor expectations of chemistry lab reports, the following
report is provided as a model for you to follow in writing your own report.  Each report
is unique to the experiment conducted, but this model shows the expected sections
that should be included and models acceptable ways to present the information.  

Name:  Joe Chemistry Student

Title: Popcorn Popping

Date: September 6, 2006

Purpose:     Is there a correlation between kernel mass of unpopped popcorn and the mass and volume of the popped popcorn flake? 
                  What does this reveal about the mechanism of popcorn popping?

Procedure:

Five typical popcorn kernels are carefully weighed to the nearest 0.1 milligram.

Each kernel is then individually popped in a heated Erlenmeyer flask. The resulting flakes (popped kernels) are carefully weighed
to the nearest 0.1 milligram.

The volume of the flake is determined by displacement of sea sand in a graduated cylinder. Precisely fill a 50mL graduated 
cylinder with 25 mL of sea sand. Pour out several milliliters of sea sand into a second container. Place the flake in the graduated
cylinder and cover the flake carefully with the previously removed sea sand, tapping the cylinder gently to cause the sand to fill the
void volume around the flake and form a flat surface. Record the new total volume of the sand-flake mixture.

Results:

    Raw Data¹       

Calculations

    Sample Calculations

        Sample 1         Mass Lost (%) = [(Kernel Mass – Flake Mass)/Kernel Mass]*100

Graphs 

            Graph 1

            Graph 2

Conclusion: The proposed mechanism for the popping of corn kernels suggests that the pericarp bursts from the pressure
of superheated water vapor contained in the soft endosperm inside. In this experiment, the mass lost upon flake formation 
averaged 10.1 (+/-1.6)% which is consistent with the hypothesized mechanism. In Graph 1, a plot of kernel mass versus 
flake mass shows a strong linear correlation even for this relatively small number of kernels tested. This is consistent with the 
loss of water from the endosperm which is necessarily larger for larger kernels and smaller for smaller kernels. Reportedly, 
popcorn processors try to carefully maintain kernels at 13-14% water for ideal flake formation.¹

On the other hand, a very poor linear correlation is observed in Graph 2 for kernel mass versus flake volume. At least for this 
small sample set, heavier kernels do not necessarily lead to bigger flake sizes. Some other factor(s) must be governing the 
ultimate size of a popped kernel. These trends naturally extend to the flake density observed which is not constant. In this 
experiment, the flake density was found to be 0.13 (+/-0.02)g/mL.

Aside from the physical measurements and relatively small number of kernels examined, several sources of error can be identified. 
Uneven heating of kernels, damaged kernel hulls, and varying initial water content of the kernels could give rise to errors in the 
experimental values.  This experiment indicates a water content of about 10% by mass while the expected value should ideally be
13-14% by mass according to typical manufacturer specifications.

References:

    1. Fantini, J.L.; Fuson, M.M.; Evans, T.A. Popping Popcorn Kernels: Expanding Relevance with Linear Thinking. J. Chem. Ed. 2006, 83: 414-416.