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The Physics of Hot Pockets
StartsWithABang (3485481) writes "You've all had the experience: you're all excited to microwave your favorite snack. So you pull it out of the freezer, you throw it in, and you let it rip. A minute or two later, you pull it out, and there it is: boiling on the outside, frozen in the middle. Finally, a physicist answers the eternal question: why do microwaved foods remain frozen on the inside when they reach scalding temperatures on the outskirts? Starts With A Bang explains the whole phenomenon. Bonus for the crisping sleeve explanation!"
Also those with rotating microwave trays (because microwaves tend to heat unevenly) ought to be aware that anything at the center of the tray will not get the benefit of rotation and heat at the same rate the entire time. To roll around in a (relatively) even distribution, none of your food should sit in the center of the tray.
a microwave with more than 300 watts of power. I've never had the issue of hot outside/cold inside, my problems have always been of the hot outside/nuclear inferno/solar coronal mass ejection on the inside variety, regardless of where I've microwaved them. I don't even follow the instructions on the package very closely, just pull it out of the wrapper, put it in the sleeve, toss it in, slap the door shut, 3 or so minutes, and out comes an external breading hot to the touch with napalm in the center. Maybe there are just a lot of broken microwaves, or even more likely, people that don't know how to use them properly?
Most microwaves have a power control. 90 seconds at power 2 or 3, wait 1 minute. Flip, 1 minute at full power. Wait 3 minutes. Serve.
There exist websites and books devoted to this appliance and how to use it correctly. This is a non-story.
Caveat: there are some nice physics going on in the explanation but only for the layman. Look elsewhere for the gritty detail we /.ers are used to seeing.
Ever notice that Cobra Commander sounds an awful lot like Star scream?
I've never had a problem with Hot Pockets: Follow directions, learn how it works in a given microwave oven, and...done: Ridiculously-hot cheap, bubbly, unhealthy goodness.
Meanwhile, I don't need to read TFA to learn how the powdered aluminum wrapper turns RF energy into thermal energy. And I don't need TFA to know that any thing has a certain reluctance toward changing temperatures, as nothing is a perfect thermal conductor.
In fact: Dude, I've been cooking with a microwave since I was a little kid: It was the first kitchen appliance I was certified on other than -- maybe -- an electric can opener.
Up next on /.: How shoelaces work to keep our shoes on our feet, followed by a lesson in using a light switch to illuminate a dark room. Or "Toast: Why bread is caramelized only on the outside when using the every-day toaster."
*head in hands*
Kid-proof tablet..
Scalding on the outside and frozen inside is a feature: it's the Hot Pocket's way of telling you it really isn't proper nutrition.
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
I know I'm going to eat a frozen dinner so I sit it on the counter for 10 minutes before i heat it. They heat up evenly and faster.
I also nuke for a 15% longer but at 80% power.
Of course, I also gussy frozen food up too. Adding just a teeny bit of herbs, or sour cream, more vegetables or some fresh cheese can make them quite tasty.
She was like chocolate when she drank... semi-sweet at first and then increasingly bitter.
OK, so frozen stuff doesn't microwave easily, but then why does the outside heat first?
When a wave penetrates a conducting medium, it transfers energy into the medium, and as a result it gets weaker exponentially. The intensity vs. depth is given by
E=Ei*exp[-C(depth/wavelength)]
where Ei is the intensity at the surface, and C is a constant that depends on the characteristics of the medium. C is small in ice, so the wave doesn't transfer much energy initially, and most of the energy just trucks on through and out the other side. Still, there is some attenuation, so the intensity is greatest at the surface and melting occurs there first.
As soon as that happens at the surface, C gets much larger and the liquid sucks most of the energy out, getting progressively hotter. The remaining energy again encounters ice, and has almost clear sailing until it hits the water on the other side, and again heats the water.