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15677.  Sat Feb 26, 2005 6:29 am Reply with quote

Q: How do they get Teflon to stick to the frying pan?
Teflon, known to science as polytetrafluoroethylene, is a pain to work with because it's nonsticky in all directions, the pan side (the bottom) as well as the food side (the top). Teflon is a fluorinated polymer, a polymer being a passel of identical building-block molecules linked together to make a long chain--the stuff of most plastics. Fluorine, due to certain electrochemical properties you'll thank me for not explaining now, bonds so tightly with the carbon in Teflon that it's virtually impossible for other substances, e.g., scrambled egg crud, to get a chemical-type grip or, for that matter, for Teflon to get a grip on anything else. In addition, the finished Teflon surface is extremely smooth, giving said egg crud little chance to get a mechanical-type grip.

So how do they get Teflon to stick to the pan? First they sandblast the pan to create a lot of microscratches on its surface. Then they spray on a coat of Teflon primer. This primer, like most primers, is thin, enabling it to flow into the the micro-scratches. The primed surface is then baked at high heat, causing the Teflon to solidify and get a reasonably secure mechanical grip. Next you spray on a finish coat and bake that. (The Teflon finish coat will stick to the Teflon primer coat just fine.)

15770.  Wed Mar 02, 2005 11:02 am Reply with quote

The history of the Microwave is a pretty interesting one. Here it is, as told by The Southwest Museum of Engineering, Communication and Computation[/url]

here's another account for anyone who can't be bothered with the link:

Magnetrons, the tubes that produce microwaves, were invented by British scientists in 1940. They were used in radar systems during World War II...and were instrumental in detecting German planes during the Battle of Britain.
These tubes - which are sort of like TV picture tubes - might still be strictly military hardware if Percy Spencer, an engineer at Raytheon (a U.S. defence contractor), hadn't stepped in front of one in 1946. He had a chocolate bar in his pocket; when he went to eat it a few minutes later, he found that the chocolate had almost completely melted.

That didn't make sense. Spencer himself wasn't hot - how could the chocolate bar be? He suspected the magnetron was responsible. So he tried an experiment: He held a bag of popcorn kernels up to the tube. Seconds later they popped.

The next day Spencer brought eggs and an old tea kettle to work. He cut a hole in the side of the kettle, stuck an egg in it, and placed it next to the magnetron. just as a colleague looked into the kettle to see what was happening, the egg exploded.

15772.  Wed Mar 02, 2005 11:35 am Reply with quote

Nice story, but unverified:

According to legend, shortly after Raytheon perfected its first microwave oven in the 1950's, Charles Adams, the chairman of Raytheon, had one installed in his kitchen so he could taste for himself what microwave-cooked food was like. But as Adams's cook quickly discovered, meat didn't brown in the oven, french fries stayed limp and damp, and cakes didn't rise. The cook, condemning the over as "black magic," quit.

So why does food not cook as well in the microwave?

Because microwaves cook by exciting the water molecules in food, the food inside a microwave oven rarely cooks at temperatures higher than 212F, the temperature at which water turns into steam.

Conventional ovens on the other hand, cook at temperatures as high as 550F. High temperatures are needed to caramelize sugars and break down proteins, carbohydrates, and other substances and combine them into more complex flavours. So microwave ovens can't do any of this, and they can't bake either.

15775.  Wed Mar 02, 2005 4:45 pm Reply with quote

the food inside a microwave oven rarely cooks at temperatures higher than 212F, the temperature at which water turns into steam.

I like that as a germ for a question. Something like 'why do your chips stay soggy if you reheat them in the microwave'?

17230.  Wed Apr 06, 2005 8:20 am Reply with quote

"apparently" teflon kills birds


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