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- Xref: sparky sci.materials:672 sci.misc:1545
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- From: meltsner@crd.ge.com (Kenneth J Meltsner)
- Newsgroups: sci.materials,sci.misc
- Subject: Re: Pop Corn Physics and Chemistry
- Message-ID: <1992Sep1.132722.6257@crd.ge.com>
- Date: 1 Sep 92 13:27:22 GMT
- References: <m0mPFSn-000FNAC@wet.uucp>
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- Organization: GE Research and Development Center
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-
-
- In article <m0mPFSn-000FNAC@wet.uucp>, wet!noah@well.sf.ca.us (Noah
- Spurrier) writes:
-
- |>Anyone out there interested in some amateur physics and chem of pop corn?
- |>
- |>I am looking for any information or references to the physics and chemistry
- |>of pop corn. What is the velocity of the pop (i.e. How long does it take
- |>to go from kernel to pop corn?) What is the mechanism of the pop? What
- |>temperatures and pressures are formed inside the corn kernel in order for
- |>it to pop? Why does the material inside the kernel behave the way it does?
- |>Do any other grains behave this way? Do we get Rice puffs the same way we
- |>get poped corn?
-
- Well, if I could find my 10th grade science fair project, I could send
- you a pretty good summary. It concerned the use of a vacuum to
- enhance the popping of corn.
-
- Here's what I remember:
-
- Corn pops because heat converts internal water into steam, which at
- around 400 F explosively breaks the kernel's shell and expands. The
- shell must be pretty hard, since there was no appreciable difference
- in popping temperature in a vacuum. Rice and wheat pop in about the
- same way, although they lack the hard shell that makes popcorn "pop"
- -- they tend to puff instead, but in both cases it's due to expansion
- of steam.
-
- You could probably figure out the vapor pressure of water at 400 F to
- get a good estimate of the maximum internal pressure in the corn
- before it pops.
-
- Professor C. Gene Haugh of Purdue University graciously answered a
- number of questions for me fifteen years ago; I have no idea whether
- he is still there. I still have my autographed "Orville Redenbacker"
- popcorn cookbook, though. There's an American Popcorn Institute
- somewhere; you might check on the back of popcorn containers or call
- one of the big packers.
-
- The folks that worry about these things are called "agricultural
- engineers," not materials engineers, but I thought I'd answer this one
- since it was the start of my scientific misadventures.
-
- ===============================================================================
- Ken Meltsner | meltsner@crd.ge.com (518) 387-6391
- GE Research and Development Center | Fax: (518) 387-7495
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