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View Full Version : Why don't microwaves heat food evenly?

attgig
11-20-2008, 10:06 AM
I can understand defrosting a huge chunk of meat. and it defrosts badly. but today for lunch, I had some leftover chicken wings. I had them laid out flat on a plate, and the ones on the edge got really hot, while the ones in the middle weren't that hot. Why is that? and if so, then, should i be putting my food in the corners of my microwave to get hot the fastest?

DarkFury
11-20-2008, 11:15 AM
One reason... "moisture".

Microwaves heat on the priciple of "exciting" the molecules of water in a particular food to generate heat. Those water molecules would have to be evenly distributed through the food being heated for it to "heat evenly"... also you'd have to consider the density of the food being heat and the amount of water molecules needed to be "excited" in order for it to heat up.

Every heated a cup of water in the microwave? It doesn't matter where in the microwave it is placed, the top, bottom, and sides of the "water" will all heat up at the same time. You wont find the top of the cup hot while the bottom is cold.

However with solids, you just don't get the consistent moisture to heat evenly througout the food.

You can get some more info on this here: http://home.howstuffworks.com/microwave2.htm

Another thing is... based on the way the waves bounce around in a microwave, the corners of the oven probably get alot more bounced waves than the center, therefore that might explain why the wings you had on the edges got hotter than the ones in the middle. Perhaps that's why they sell those "rotation plates" to spin your food around so that they get maximum coverage from the various angles. :D

attgig
11-20-2008, 12:26 PM
It doesn't matter where in the microwave it is placed, the top, bottom, and sides of the "water" will all heat up at the same time.

Another thing is... based on the way the waves bounce around in a microwave, the corners of the oven probably get alot more bounced waves than the center

so, perhaps, putting it in the corner of the microwave WILL heat it up a bit quicker....

but yeah, so, are a lot of the microwaves come directly horizontally verses from the top or angled?
That's the only way i could think of why the wings on the edge of the plate get hot faster than the ones in the middle....

DarkFury
11-20-2008, 01:07 PM
I don't think the waves are horizontal... They are probably angled hitting the corner then hitting the opposite corner in the bounceback (kinda like shooting a cueball into a corner bumper hitting the adjacent corner on the bounce).

Napoleon54
11-20-2008, 06:53 PM
This reminds me of Jim Gaffigan's bit on Hot Pockets.

"Is your hot pocket cold in the middle?"
"It's frozen. But it can be served boiling lava hot."
"Will it burn my mouth?"
"It'll destroy your mouth."

InfiniteNothing
11-20-2008, 09:29 PM
Different microwaves have different hot spots. Try putting your food on the edge of the spinning disk. I generally try and cover my food to get a bit more convection going.

Jeffbx
11-21-2008, 04:41 AM
If you don't have the little spinning tray, you'll want to rotate whatever you're heating a few times to make it more even.

That's also why you see warnings about how you should never heat baby bottles in the microwave - even liquid heats unevenly & if you don't shake the bottle after you heat it, the baby could get a hot spot & burn their mouth.

ArkiStan
11-21-2008, 10:09 AM
off-topic question:
who here actually makes a conscious effort not to stand in front of a running microwave?

DarkFury
11-21-2008, 10:52 AM
off-topic question:
who here actually makes a conscious effort not to stand in front of a running microwave?
Today's microwave ovens are usually properly shielded thus do not present a hazard to us if we stand near them.

Now if your unit is an older one (and I'm talkin'... OLD, like in one with rotary controls and faulty latches.) then I'd probably be wary of standing near one of those.

DarkFury
11-21-2008, 10:57 AM
That's also why you see warnings about how you should never heat baby bottles in the microwave - even liquid heats unevenly & if you don't shake the bottle after you heat it, the baby could get a hot spot & burn their mouth.
Also "consistency" of the water mixture might be in play here...

Shaking it up, mixes the consistency... so I could see part of of that bottle getting warmer than another. However, on top of that, you pretty much have to watch out for how fast a microwave can take a water molecule to the boiling point. When you stove top warm a bottle, you really don't let the water around the bottle boil before you remove the bottle. Therefore, a microwave probably heats the bottle way too quickly and way too hot to be served to a baby. :D

Napoleon54
11-21-2008, 04:12 PM
Today's microwave ovens are usually properly shielded thus do not present a hazard to us if we stand near them.

Now if your unit is an older one (and I'm talkin'... OLD, like in one with rotary controls and faulty latches.) then I'd probably be wary of standing near one of those.
Oh man, we had one of those at my old work. The thing was freakin' scary but it sure did zap things quickly.