How does a microwave cool down so fast?

Question

It can heat up anything in seconds but as soon as you open up the door and stick your hand in there its as if it hadnt even been used.

Answer 1

Microwaves heat up water and fat molecules in the food.
The air and the plastic does not heat up by the microwaves.
That's why you don't feel any heat after you use a microwave.

Gas and electric ovens work by heating the air and the metal in the oven which then transfers the heat into the food.

That's why it takes longer for food to warm up in an oven and why you still feel heat after an oven is used.

Answer 2

A microwave oven does not cool down because it does not generate heat. You have already gotten answers that tell you how they heat the food.
I am going to add a little bit about what microwaves are and how the oven works. Microwaves are very high frequency radio waves. They will pass through most everything except medal. That is why ovens have medal sides, to keep the waves bouncing around inside. An early range was called the “Radar Range”. Microwave radiation is what radars use. In fact the reason a little microwave is so heavy is because of a huge magnet that is part if the tube that generates the waves. It is called a Magnetron, the same tube that was used in radar. The tube only pulses from time to time generating the waves. The waves bounce around for a short time.
You are probably now wondering why the microwaves do not pass through the glass door. If you look at the glass you will see a medal screen. The size of the holes in the screen are smaller then the wave height of the microwaves so they cannot pass through.

Answer 3

Cool Microwave

Answer 4

A microwave cooks with radio waves. These heat the water in the food rather than the air around the food. That is why the oven and most microwaveable dishes stay cool while the food gets hot.

Bert

Answer 5

Microwaves "bounce" off of metal. Therefore, we cook in a six sided metal box so they won’t get out into the room. This makes them very safe to use. They pass through plastic or glass, like sunshine goes through a window pane, with no effect at all. Therefore, we cook in utensils made from these types of materials. The microwaves are attracted, like magnets, to the fat, sugar and water within the food. Water molecules are very good absorbers of microwaves, sugar and fat are better and salt is best. Thus, foods high in fat, sugar and salt will cook faster and get hotter than foods made up primarily of water such as vegetables.

Microwaves penetrate the foods about 1 inch in all directions (top-bottom and sides) causing the water molecules to move and vibrate against one another at the rate of 2 1/2 billion times a second. The microwaves don’t actually cook the food. The friction caused by the vibrating molecules produce the heat which does. Microwaves do not actually touch most of the food they cook. The heat from the vibrating molecules on the outer edges of the food must go somewhere. It is by "conduction" this heat moves inward, layer by layer, to cook the food. Therefore, cooking larger, more dense foods starts on the edges and heat is conducted to the center.

http://www.hungrymonster.com/recipe/Microwave/How_Microwave_Ovens_Work.cfm

Answer 6

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This is because the microwave oven is not heating up the air inside the oven. It is only heating up the object that you've placed in there.

We are being bombarded with microwaves all the time. They are in the air all around us. All the oven does is focus them on the item(s) being cooked. The item gets hot, but the air in-between does not.
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Answer 7

micro waves do not heat up like gas/electric ovens to heat the food. they use electromagnetic waves that do the job. so there is no heat being produced to linger around after the job

Answer 8

Because there is no heat. You food is being cooked by an electromagnetic wave, hence the name micro wave.

Answer 9

there is no heat
Micro wave = very high frequency radio waves
the water in the food at the molecular level become hot to do the cooking.

Answer 10

welp, everybody prety much said the same answer here, and they are all pretty much right. in school i learned that they dont use heat at all it has to do with the frequency of the waves and their strenghth (i dont exactly remember but i think that was why)