How a Microwave Oven Works

Bill details how a microwave oven heats food. He describes how the microwave vacuum tube, called a magnetron, generates radio frequencies that cause the water in food to rotate back and forth. He shows the standing wave inside the oven, and notes how you can measure the wavelength with melted cheese. He concludes by describing how a magnetron generates radio waves. You can learn more about the microwave oven from the EngineerGuy team's new book Eight Amazing Engineering Stories http://www.engineerguy.com/elements

• Category

  Science & Technology

[ianovaril]

It's a common misconception that microwaves "irradiate food" due to microwaves being a form of "radiation." In actuality, as Bill talks about in the video, microwaves causes water molecules to spin, and thus heat your food by way of friction. Microwaves as a form of radiation actually have less energy than visible light, and so are not going to irradiate your food, or by extension, give you cancer. In short; no they cannot. Enjoy your quickly cooked food!

[R N]

yes, if your eat enough microwaves they can give you cancer.

[FuzzleLand]

Cooks the whole food simultaneously? Tell that to my hotpockets. 

[2t22tornadosiren]

Microwaves don't actually cook the food, it just makes it hot really fast. The maillard reactions that actually cook food and kill bacteria take a while.

And microwaves don't kill salmonella

[Dasyati]

That's the idea behind "microwave-safe" containers; they're made only from materials which aren't dipoles, so they stay relatively cool while the food itself heats up.

[Encephthy]

No

[Alromani™]

This is not the reason Microwave is dangerous

It is not the effect on food but on humans .. if you stand near it while it is on full power I'm pretty sure some of those radiation will be leaking out and people put the food and cook it in plastic packaging which might react with the food that's what might be the cause of cancer

[marzolian]

Question: the manuals for some home microwave ovens (late 1970's) pictured a scattering device, installed in the roof of the oven. It looked something like a room cooliing fan, and rotated relatively slowly. The diagrams in the manual described how this scattered the waves. It made sense. Is this used in microwaves today?

[Babelfish112]

Awesome explanation! Well done :)

[Jean LaMantia]

Thank you, that was excellent.

[ryanonism]

so lets say we put something that doesnt contain water it wouldnt heat up? so let say we have pure dry ice it wouldnt heat up and sublime since CO2 isnt a polar molecule. (of course assuming that the inside of the microwave has a temperature below the temperature at witch CO2 sublimes.