Popcorn making is a fascinating process marked by soft percussion and a toasty scent. This process transforms tough seeds into cloud-like puffs. But how did we end up with this whimsical food?
All the corn we consume today is derived from a tall grass called teosinte. Indigenous people in what is now southern Mexico began selectively breeding teosinte about 9,000 years ago. An ear of teosinte originally yielded somewhere between 5 and 12 small kernels, each with a hard shell called a pericarp. Some varieties had a fantastic feature: if they reached a certain temperature, their kernels exploded.
Popcorn kernels pop because water and starch are sealed tightly within the pericarp. When heated, the moisture inside becomes steam. As it expands, it increases the internal pressure and the solid starch transforms into a gel-like substance. The pressure finally overcomes the pericarp’s resistance and it bursts—the steam and starch expanding to form a foam that quickly cools and dries in the air. This small-scale explosion also rushes forth the compounds that give popcorn its powerful aroma.
Ancient Indigenous American people cultivated other maize varieties with larger, more flavorful kernels and thinner pericarps. But the hard-shelled, poppable variety also persisted and spread through parts of the Americas. By the time European colonizers arrived in the late 1400s, Indigenous American people were preparing and eating corn in myriad manners. Popcorn wasn’t a major part of their diets. But it popped up in European accounts, which described the preparation of “toasted” or “parched” corn and its use in some Aztec feasts and celebrations.
Despite initial reluctance, colonizers eventually began cultivating—and popping—corn. The methods they used at first were inconsistent and messy. But with the invention of “wire over the fire” baskets around 1837, the process got easier. Soon, popcorn picked up steam and exploded with a reputation as a low-cost, entertaining snack. Over the following decades, it became a mainstay at events and hundreds of recipes materialized, mixing popcorn with sweet and savory ingredients.
At the 1893 World’s Fair, an inventor showcased the first popcorn machine: a wagon that tossed popcorn in seasoning as it cooked. Soon enough, vendors could be seen roving US city streets with similar machines. Interestingly, movie theaters were some of the only American venues where you wouldn’t find popcorn at the time. Many cinema operators saw their establishments as part of a grand theater tradition at odds with popcorn—what they considered a messy, low-brow street food.
However, when the Great Depression hit in 1929, movies provided the public with a welcome distraction. They had recently gone from being silent and subtitled to acquiring sound, making them accessible to a wider audience, including non-literate people. At about five or ten cents a bag, popcorn proved an inexpensive luxury for moviegoers, so theater operators pounced on the money-making opportunity. Today, a medium bag of popcorn might cost about 60 cents to make, but retail for around $6—a 1,000% markup. Popcorn sales generate nearly 40% of all movie theater profits, helping to offset the high prices that theaters pay film studios.
Over the last century, people throughout the Americas continued popping corn, and different preparations took hold in markets worldwide. When microwavable popcorn was launched in the 1980s, popcorn popped off yet again. Dozens of kinds of popcorn are now grown in the US. Different strains assume distinctive shapes when their kernels explode, most commonly taking so-called “mushroom” and “butterfly” forms. And they’ve been bred for supreme poppability. Over the last century, the amount that popcorn expands has doubled: now, kernels can reach up to 50 times their original size upon popping. Not to be corny, but popcorn’s come a long way.
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Measure out a small amount of popcorn kernels and observe them closely. Predict what will happen when they are heated. Then, with the help of an adult, pop the kernels and observe the changes. Write down your observations and explain why popcorn pops based on what you learned about water, starch, and pericarp.
Create a timeline that traces the history of popcorn from its origins with teosinte to its popularity today. Include key events such as the invention of the popcorn machine and the introduction of microwavable popcorn. Use drawings or printed images to make your timeline visually engaging.
Use popped popcorn to create a piece of art. You can glue the popcorn onto a piece of paper to form shapes, letters, or even a scene. While working on your project, think about how popcorn has transformed from a simple seed to a fun and versatile material.
Invent your own popcorn recipe by mixing popcorn with different ingredients. You could try sweet, savory, or even spicy combinations. Write down your recipe and share it with your classmates. Explain why you chose those ingredients and how they complement the taste of popcorn.
Research how different cultures around the world prepare and enjoy popcorn. Create a short presentation to share with your class. Include interesting facts and images to show the diversity of popcorn preparations and its significance in various cultures.
popcorn – a type of corn that expands and puffs up when heated, typically used for making a popular snack food. – I love snacking on popcorn while watching movies.
seeds – a flowering plant’s unit of reproduction, capable of developing into another plant. – I planted a few seeds in my backyard and now I have a beautiful garden.
teosinte – a wild grass native to Mexico, believed to be the ancestor of modern corn. – Genetic studies have shown that teosinte is the closest relative to cultivated corn.
kernels – the edible part of a grain or nut, typically a hard or tough outer shell containing the seed. – I prefer to eat popcorn kernels rather than the popped ones.
pericarp – the outer layer or covering of a fruit or seed. – The pericarp of an apple is usually thin and easily eaten.
starch – a complex carbohydrate that is the main energy storage molecule in plants. – Potatoes are a good source of starch.
steam – the vapor into which water is converted when heated, used for cooking or heating. – I like to steam vegetables to retain their nutrients.
foam – a mass of small bubbles formed on the surface of a liquid, typically by agitation or fermentation. – The beer had a thick foam on top when poured into a glass.
aroma – a distinctive, typically pleasant smell. – The aroma of freshly baked bread filled the kitchen.
cultivation – the process of preparing and working on land to grow crops or plants. – The cultivation of rice requires specific techniques to ensure a successful harvest.
