Why do popcorns pop?

Answer 1

Interesting question .... here's the answer ...

Only popcorn kernels can pop, and the secret is water. Each kernel contains a small amount of water stored in a circle of soft starch inside the hard outer casing. When heated to around 450? F, the moisture turns to steam, creating pressure within. As the pressure builds, the casing eventually gives way, and the kernel explodes and pops, allowing the water to escape as steam and turning the kernel inside out.

Answer 2

Because unlike most other grains, the outer hull, or pericarp, of the popcorn kernel is thick and impervious to moisture.

As the kernel is heated past the boiling point, water in the kernel begins to turn to steam, generating an internal pressure of about 9 atm. In kernels of other grains (and in damaged kernels of popcorn), this steam escapes as fast as it forms, but in the tightly sealed popcorn kernel, the steam is held tight by the pericarp and the pressure starts to build until the pericarp suddenly ruptures, causing a small explosion. The force of the explosion turns the kernel inside out. More importantly, because the moisture is evenly distributed throughout the starchy endosperm, the sudden expansion turns the endosperm into an airy foam which gives popcorn its unique texture.

Two explanations exist for kernels which do not pop, known in the popcorn industry as "old maids," after being exposed to high temperatures. The first is that unpopped kernels do not have enough moisture to create enough steam for an explosion. The second explanation, according to research led by Dr. Bruce Hamaker of Purdue University, is that the unpopped kernel may have a leaky hull.

Answer 3

Pressure. It's a closed system. There is some liquid inside. As you heat the kernal the pressure inside increases. At some point the internal pressure exceeds the force the shell can contain. Then it pops. You'll notice that the hull, or shell, is still present on a popped kernal. Ever boil anything on the stovetop with a lid on it. As it starts to boil the lid starts jumping around and you'll see steam escaping. That's the same type of pressure escaping a little at a time. If you sealed the lid to the pot, at some point, it would explode as well.

Answer 4

There is a small bit of water within the kernal. Heating the popcorn changes it to steam and POP!

Answer 5

Because of the moisture inside the popcorn kernel. When it is heated, the chain reaction of expansion makes it 'pop'.

Answer 6

It has to do with the moisture content in the kernel of the corn. When heat is introduced the kernel inside the brown shell swells and bursts the shell.

Here is a really good link to explain:

http://maize.agron.iastate.edu/popcorn.html

Answer 7

Heat causes the water in the kernel to expand into steam which then causes the kernel to pop so the steam can escape.

Answer 8

There is moisture inside the kernal. When it heats up, it turns to steam. The steam tries to escape, but it can't so it causes the kernal to burst open.

Answer 9

Because when it reaches a certain temp they just explode into nice little warm pop cornies !

Answer 10

because they don't like jazz. why do eggs explode when put in the microwave?