It’s hard to imagine attending the latest blockbuster without a jumbo bucket of excessively buttery, salty popped corn. (Or, at least, getting a whiff of it.)
Popcorn was hugely popular at fairs and carnivals in the mid-1800s. Street vendors were able to easily make and sell the delicious, aromatic snack food by the bag when the first steam-powered popcorn maker was created in 1885. However, movie theaters wanted to stay far, far away from the pungent, crunchy grub.
They strove to associate themselves more with the latter half of their name: the theater. A real theater would refuse to be associated with food that would be noisily chomped on and messily strewn about by consumers during showings. Before talkies, literacy was a necessity for film-goers, and movie theaters strove to target a well-educated crowd.
In 1927, with the dawn of talkies, movies were no longer just geared toward a "sophisticated" and literate audience. Going to the movies was an activity anyone could enjoy. This coincided with the Great Depression, and Americans wanted cheap entertainment that would help them to get lost in a new reality. Movies fit the bill.
Although early theaters weren’t equipped to handle popcorn machines, independent vendors were quick to jump at the opportunity of selling directly to consumers. Corn kernels were cheap, so popcorn was inexpensive (ranging from five to ten cents a bag) and patrons who were not well-off could enjoy a bag of the goodness. Vendors began selling popcorn to people outside of the theater, allowing for a double profit of simple passersby and film-goers alike. The snack was everywhere. Soon, vendors could, for a small fee, sell popcorn in the lobby directly to people entering the theater.
Movie theater owners began to cut out the street vendors and sell popcorn themselves. Theaters that refused to change with the times and have their own popcorn makers suffered, as the cheap snack became in-demand. (One theater owner even lowered the price of his movie tickets in order to encourage people to come for the food.) For theater owners, the way to stay alive during the Depression was to give the people what they wanted.
During World War II, the sales of popcorn in the United States really took off. Sugar was sent overseas for the military, so there were not as many resources for the creation of candies and soda. Meanwhile, there was no salt or kernel shortage. The food's popularity continued to grow, and the rest is movie history.