Submitted by: Oonagh S.Last updated: 9/28/11

We all love popcorn at the movies...

Everyone loves a bucket of buttery, hot popcorn with a Coke at the movies, but no one bothers to think about how and why popcorn does what it does and how it pops.


The process of preparing the popcorn is actually quite complicated. First of all, you have 25 different types of flint corn (maize) to choose from. But, most commonly, 23 types of these are ignored, and the lucky two, pearl and rice popcorn are used.

So many sections…

If you look at the picture below, you can see that a popcorn kernel has many layers. The outer layer, or hull, is the hard, brown section we see whenever we look at one of the kernels. Inside, many layers of starch and other substances surrounds the germ, the part which bursts through to transform the kernel into the popcorn that we consume.

There are so many parts in a little popcorn kernel

The Whole process…

You may be wondering, how does popcorn pop? What do these layers of starch have to do with it all? Well, these layers of starch all contain levels of moisture at roughly 13.5%. This moisture, when heated to about 200° Celsius, boils. The moisture evaporates when the water particles start to vibrate faster and faster until the pressure increases (boiling). When the water vapor pressure becomes greater than the air pressure, the outer kernel cannot bear the newly introduce force, therefore, it gives way, allowing the starch (the germ) to break through and become a large, fluffy mass about twenty to forty times the original size. See diagram below for more information.

It's quite a process to prepare the kernel inside...

The special treatment…
In popcorn factories, the kernels are put through quite a process. First a piece of equipment individually adjusts each kernel’s moisture levels so that they reach 13.5%. After this step, another machine goes through and discards most of the kernels with the incorrect moisture levels. This is apparently a very tedious process, but it ensures that we can enjoy the delicious snack.


"popcorn." Encyclopædia Britannica. Encyclopædia Britannica Online School Edition.

Encyclopædia Britannica, Inc., 2011. Web. 23Sept. 2011.

"boiling." Encyclopædia Britannica. Encyclopædia Britannica Online School Edition.

Encyclopædia Britannica, Inc., 2011. Web. 23 Sept. 2011.
Wikipedia contributors. "Popcorn." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 22 Sep. 2011. Web. 23 Sep. 2011.
Popcorn. Prod. Digital Ranch Productions. Discovery Channel, 2008. Discovery Education. Web. 27 September 2011.


Condensate- When a liquid is reduces from a gas to a vapor.
Boil- To change from a liquid to a gas; to process of evaporation.
Evaporate- To change from a liquid or solid into a vapor.