Popcorn, a cereal grain like wheat or oats, is about 75% carbohydrate (starch) with smaller amounts of protein, fat, minerals, and water. The water plays a critical role in the popping process. To ensure maximum popping expansion, the corn is carefully cured (dried) until it reaches a certain percentage of water, which you will determine in this lab.
What is the percent composition of your brand of popcorn? Which brand of popcorn has the highest percent composition of water ?
Each group will be testing a different brand of popcorn. Half the class will use microwave popcorn and the other half will use an old fashioned popper
Microwave popcorn Directions:
1. Use the scale to determine the mass of the bag of unpopped popcorn kernels.
2. Place the bag in the microwave oven and cook the popcorn.
3. Open the bag to let the steam (water) escape. CAUTION: Hold the bag away from your body when opening to avoid contact with the steam!
4. Use the scale to determine the new mass of the bag of popped popcorn kernels.
5. Calculate the difference between the mass of the popped popcorn (step 4) and the mass of the unpopped kernels (step 1).
Mass of the Unpopped Popcorn
Mass of the Popped Popcorn
Mass of Water
Percent Water in Popcorn
1. Make a popcorn popper out of two foil bowls using one as a lid and fastening them
together with 4 paperclips.
2. Add a small amount of oil. Measure the mass of popper and oil (including
3. Add 10-20 kernels of popcorn and use the paperclips to fasten the lid to the base.
Measure the mass of the popper, oil, and corn.
4. Pop the popcorn on a hotplate until all kernels have popped. Use the crucible tongs to
keep the popper moving to avoid scorching. If the heat is too high, raise the popper
above the hotplate.
5. Let the popper cool. Measure the mass of popper, oil, and popped corn.
Mass of the popper and oil
Mass of the Popper, oil and corn
Mass of popper, oil and corn after
Mass of water
Percent Water in Popcorn
Calculate the percentage lost using the following formula:
percentage lost = original mass (step 1) – final mass (step 4) X 100%
original mass (step 1)
Questions: (Use the back, or additional paper, to answer the questions below. It is imperative that you defend your answers where I have directed you to do so.)
1. Why does popcorn pop? Defend your answer!
2. Did all of the popcorn pop? Why or why not – defend your ideas!
3. How do you account for the missing mass, and how much was lost?
4. How does the presence of unpopped kernels affect the percentage composition of the water you calculated? Defend your answer!!
5. What could you do to make these calculations more accurate?
6. If you had a bag of popcorn that was twice as big as the one used in this activity, what would you expect to happen to all the masses involved? (Answer for each mass.)
a. Original Mass
b. Final Mass
c. Mass Lost
7. Considering that same bag of popcorn as described in question 4 (twice the size of the one you popped), what would you expect the PERCENTAGE lost to be? The
same, larger, or smaller? Why?
8. What conclusions can you make regarding the differences in the popping methods?
9. Which brand was the best?