A “which popcorn pops the best” project is one of the most reliable science fair experiments because it produces measurable data, uses cheap materials, and has real science behind it. The basic idea is simple: pop several brands or types of popcorn under identical conditions, then measure which one produces the most popped volume, the fewest unpopped kernels, or both. Here’s how to design a strong version of this project and understand the science that makes it work.
Why Popcorn Pops in the First Place
Every popcorn kernel has three parts: a tough outer shell called the pericarp, a starchy interior called the endosperm, and a small germ. The endosperm contains both starch and water. When you heat a kernel, that water turns to steam and builds pressure inside the shell. The pericarp on popcorn is about four times stronger than the shell on regular corn, so it holds that pressure in until the kernel finally ruptures. At that moment, the superheated starch expands outward into the fluffy white shape you recognize.
The pericarp is so critical that removing it almost entirely eliminates popping. Research has shown that stripping away the outer shell causes a 90% drop in a kernel’s ability to burst. A thicker, more intact pericarp generally means better popping. The composition of the shell matters too: the amount of a structural compound called lignin in the hull contributes to how well the kernel expands.
What “Best” Actually Means
The popcorn industry measures quality using two main metrics. The first is the expansion ratio, which compares the volume of the popped corn to the volume of the unpopped kernels. Good commercial popcorn expands at least 35 to 38 times its original volume, and top hybrids can exceed 40 times. The second metric is the percentage of kernels that actually pop. High-quality popcorn should pop at least 98% of its kernels, leaving under 2% unpopped (sometimes called “spinsters” or “old maids”).
For your project, you can measure one or both of these. Counting unpopped kernels is the easiest approach. Measuring popped volume with a large bowl or measuring cup gives you the expansion data. Using both metrics together makes for a stronger project because a brand might pop most of its kernels but produce smaller, denser pieces.
Choosing Your Variable
A good science fair project tests one variable at a time. You have several options for what to compare.
- Brand to brand: Buy three or more brands of plain popcorn kernels (not microwave bags) and pop the same number of kernels from each under identical conditions. This is the most common version of the project.
- Kernel type: Compare butterfly popcorn to mushroom popcorn. Butterfly kernels burst into irregular shapes with “wings” that catch butter and salt well. Mushroom kernels expand into round, compact balls with fewer hull fragments. They pop differently because of their internal structure, and you can measure whether one type produces more volume or fewer duds.
- Moisture content: This is a more advanced version. Take kernels from a single brand and split them into three groups: one stored normally, one soaked in water overnight, and one dried out in a low oven or left open for several days. Research published in the Journal of Food Engineering found that kernels with about 14% moisture content produce the best results, including the highest volume, the largest individual flakes, and the fewest unpopped kernels. Kernels that are too dry or too wet perform significantly worse. This version lets you explain a clear scientific mechanism in your report.
- Popping method: Compare an air popper, a stovetop pot with oil, and a microwave. The same study found that the popping method significantly affects expansion volume and flake size. If you go this route, use the same brand and quantity for each method.
Setting Up the Experiment
Count out a specific number of kernels for each trial rather than measuring by volume or weight. Somewhere between 50 and 100 kernels per trial works well. This makes it easy to count unpopped kernels afterward and calculate a precise percentage. Run at least three trials for each group so you can average your results. Science fair judges look for repeated trials because a single run can produce a fluke.
Keep everything constant except your one variable. If you’re testing brands, use the same popping method, the same heat setting, the same amount of oil (if any), and the same timing for every batch. If you’re using a microwave, use the same microwave at the same power level. Write down every detail of your procedure so it could be repeated by someone else.
To measure popped volume, pour the finished popcorn into a large measuring cup or a bowl you’ve pre-measured with water. A container that holds at least 2 to 3 liters gives you room to work with. To count unpopped kernels, pick through the popped corn carefully and set aside anything that didn’t fully open. Partially popped kernels (cracked open but not expanded) count separately from fully unpopped ones if you want an extra data point.
Recording and Presenting Data
Create a data table with columns for the brand or condition, trial number, number of unpopped kernels, percentage popped, and total popped volume. After all trials, calculate the average for each group. A bar graph comparing average popped volume across brands is visually clear for your display board. A second graph showing the percentage of unpopped kernels reinforces your findings.
If one brand pops 95% of its kernels while another pops 88%, that’s a meaningful difference. If two brands are within a kernel or two of each other across multiple trials, that’s also a valid finding: it means they perform about the same, which is worth reporting honestly.
The Science Behind Your Results
Your report will be stronger if you explain why some popcorn performs better. The three biggest factors are moisture content, pericarp integrity, and the type of starch inside the kernel.
Moisture is the fuel for the whole process. Below about 11% moisture, there isn’t enough water to generate the steam pressure needed for a full pop. Above about 15.5%, the extra water can make kernels soggy and reduce expansion. Commercial producers carefully control moisture to hit that sweet spot around 14%. Cheaper or older popcorn that has been sitting on a shelf may have dried out, which would explain lower performance.
Pericarp quality varies between hybrids. Research on different popcorn varieties has found statistically significant differences in expansion volume between genetic lines, with some hybrids expanding to ratios above 33 while others stayed below 28 under the same conditions. The kernels that expanded more had thicker, more structurally sound hulls that held pressure longer before bursting. This is something manufacturers select for when breeding popcorn varieties, and it’s one reason name brands sometimes (but not always) outperform store brands.
Starch structure also plays a role. Popcorn starch is naturally puffier than the starch in regular corn. When steam converts that starch into a gel-like substance inside the pressurized kernel, it’s primed to expand rapidly once the hull gives way. Different popcorn varieties have slightly different starch compositions, which affects how fluffy or dense the final product turns out.
Tips for a Stronger Project
Store all your popcorn in sealed containers at room temperature before testing. Kernels left in open bags lose moisture to the air, which could skew your results. If you’re buying microwave popcorn instead of loose kernels, be aware that the bag size itself affects results. Research has shown that larger microwave bags produce higher expansion volumes than smaller ones, simply because the popcorn has more room to expand. If you’re comparing microwave brands, try to choose bags of similar size.
For your hypothesis, make a specific prediction and explain your reasoning. “I think Brand X will pop the best because it is a premium brand that may use a higher-quality hybrid with better moisture control” is stronger than “I think Brand X will pop the best because it is popular.” Even if your hypothesis turns out to be wrong, explaining your reasoning and analyzing why the results differed is exactly what judges want to see.
Photograph each batch after popping, ideally next to a ruler or in the same container, so your display board shows the visual difference between brands. The contrast between a bowl overflowing with fluffy popcorn and one that’s half-full with a pile of unpopped kernels makes your data immediately understandable to anyone walking past your board.