primitives deal up a dish of potato math involving microwaves

[BattleHymn]

http://www.democraticunderground.com/1018702413

Fri Dec 19, 2014, 09:22 AM
Star Member Ron Obvious (3,077 posts)

Why aren't microwave times additive?

I think I have a decent understanding of how microwaves work. As molecular motion increases, heat increases and vice versa. Microwaves excite the (water) molecules in the substance being heated, and the item heats up. Therefore, the greater the mass being heated, the longer the microwave time required. Makes sense.

So why doesn't this appear to scale linearly? Example: one microwave meal A (500g) requires 5 minutes to heat to the perfect temperature. So why then, if I put two identical ones in (1000g) and give them 10 minutes, do I wind up with two thoroughly nuked meals?

A 1.5x scaling appears to work as a rule of thumb.

So why is that? Do microwaves ramp up geometrically or does this violate the known laws of physics?

Or is my microwave just strange?

Fri Dec 19, 2014, 10:29 AM
Star Member d_r (4,076 posts)
1. you mean

if you put them both in at the same time?

Fri Dec 19, 2014, 12:13 PM
Star Member Ron Obvious (3,077 posts)
2. Yes.

Sorry if that wasn't clear. Cooking one meal takes 5 minutes, but if I give two identical ones 10 minutes, they're totally overdone. Instead they require 7 and a half minutes (the 1.5x rule I mentioned earlier) to be perfectly done.

I've always thought that was strange.

Fri Dec 19, 2014, 01:19 PM
Star Member d_r (4,076 posts)
4. well

thank about it, the meal was supposed to be in there 5 minutes, but it was in there 10 minutes.

Fri Dec 19, 2014, 12:31 PM
Star Member Wounded Bear (6,073 posts)
3. It's probably something to do with volume...

If you put in just one meal, it doesn't fill much of the volume of the box, and a significant amount of the power is wasted. Putting in in two meals fills the volume more and absorbs more of the microwave energy.

It's kind of like the dryer paradox. The dryer often works more efficiently with two washer loads in it than one.

Fri Dec 19, 2014, 04:34 PM
jakeXT (8,511 posts)
6. Some claim the edge is more effective than the middle, at least in older ones.

Maybe two meals occupy more edge territory so to speak


[A link to Smarter Every Day, which I thought was interesting.  Destin Sandlin is an engineer for the military and NASA, and a professing Christian.  I wonder if the primitive bothered to watch any of his other links?]


1. The most common “cold spot” for a microwave is in the center of it, so arrange evenly sized portions of food spaced in a ring around the center for more even cooking. Or if food happens to be different sizes, place the thicker portions toward the outer edges.

Sat Dec 20, 2014, 01:44 AM
Star Member Ron Obvious (3,077 posts)
9. Could be!

But that would seem to go against my experience as it would indicate that it would take longer to cook both meals rather than less as they would both occupy more space on the edge than the centre.

Fri Dec 19, 2014, 08:21 PM
Taitertots (6,511 posts)
8. Do you add the time when you bake potatoes in the oven?

Think about it and it will make sense.

Sat Dec 20, 2014, 01:48 AM
Star Member Ron Obvious (3,077 posts)
10. No

But then hot air ovens work differently. You use the same amount of time to expose the meal to heat regardless of volume. Microwaves should - in theory - require twice as much energy to heat twice as much volume.

Sat Dec 20, 2014, 02:04 AM
Taitertots (6,511 posts)
11. But you have twice as much volume to absorb energy

All the microwaves in the microwave aren't absorbed by the food. Additional food absorbs microwaves that would be wasted.

[JohnnyReb]

DUmmie heating day old coffee.

[DumbAss Tanker]

With their understanding of cube-square (Or, in this case, cube-linear) progressive relationships, I'm surprised they don't have debates about the giant mantis/giant ant threat.

[obumazombie]

DUmmie heating day old coffee.

If it's 2 days old, it takes 1.5 times as long to nuke.

[JohnnyReb]

I am going to let out a little known secret here....if you bypass all the safety switches and stick your head in a microwave and turn it on high....it will cure sinus problems in about 3 minutes and give you a "to die for" high.

[ChuckJ]

I am going to let out a little known secret here....if you bypass all the safety switches and stick your head in a microwave and turn it on high....it will cure sinus problems in about 3 minutes and give you a "to die for" high.

If you buy a large bag of Cheetos and have your head inside the bag when you stick your head in the microwave will it also preemptively cure the munchies?

[BlueStateSaint]

If you buy a large bag of Cheetos and have your head inside the bag when you stick your head in the microwave will it also preemptively cure the munchies?

I am going to let out a little known secret here....if you bypass all the safety switches and stick your head in a microwave and turn it on high....it will cure sinus problems in about 3 minutes and give you a "to die for" high.

I'm about crying here from these activities:

 

So, H5s were given!