why does the popcorn swells, which is the chemical that makes it to swell on heating?

H2o.

http://www.nasa.gov/audience/forkids/home/popcorn.html

 

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.

Chemistry thread moved from Engineering to... um, Chemistry.

Function of pressure cooker?

Function of pressure cooker?

 

Allows the boiling water to go over 100C whilst cooking at increased pressure. Thus a faster, hotter cook.

it was very informative for me..... and for others tooo...

 

thanks iNow

You are very welcome.