How do microwave ovens cook food? Ask Smithsonian (
How do microwave ovens cook food?

Here's a hint it's in the name of the machine, and it's not the word oven. Microwave ovens use microwaves. This spectrum ranges from radio waves and microwaves, to infra-red, visible light, ultraviolet, and x-rays.

Now when you press start on your microwave oven, it fires a blast of microwaves at your food. The energy in the microwaves excites water molecules in the food. The excited water molecules vibrate back and forth producing heat. And this heat cooks your food.

The great thing about microwaves is that they are at the right frequency to excite water molecules, but don't vibrate things like metal or plastic. Which is a good thing, because who wants to eat cooked plastic?

Critical thinking challenge: What else moves back and forth to produce heat? What is the name of that force that produces heat?

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Assigned 18 times

  • TyriseJasper-Lar
    5/14/2014 - 11:46 a.m.

    its pretty amazing how microwaves work. and how they excite the water molecules to make them vibrate back and forth. its an amazing achievment. america should be very proud of what they have done for society.

  • TobiasPeters-Lar
    5/14/2014 - 11:46 a.m.

    because when you put any kind of food in the microwave it wood cook pretty good foru to eat fresh in your stomach very good for us.

    5/14/2014 - 01:06 p.m.

    I never knew this about microwaves and microwave ovens. Its very interesting. Now when I heat my food up I'll always have this in my head and remember this!!

    5/14/2014 - 10:03 p.m.

    Microwaves are a type of electromagnetic wave so most people should know a microwave cooks your food with electromagnetic waves. Although, microwaves are a less harmful type of EM wave they still cause harm to our body. It is not smart to cook your food in a microwave. Some scientist conducted a study on rats being introduce to EM waves as microwaves in there food and most of the rats ended up dying. Probably because of them being exposed to the dangerous rays. It is better cook your food in the oven or on the stove.

  • RaeC-5
    5/15/2014 - 12:44 a.m.

    This article is about how food is cooked in a microwave. Microwave ovens use microwaves. This spectrum ranges from radio waves, to infra-red waves,visible light, ultraviolet, and x-rays. Right when you press start the microwave oven fires microwaves on your food. The microwaves have lots of energy and the energy exited water molecules in the food. The water molecules vibrate back and forth which causes heat and this cooks your food. I think this is interesting and cool it all happens so quickly.

  • DelilahG-3
    5/17/2014 - 02:30 p.m.

    Microwave ovens have a special way of cooking food. Microwave ovens use microwaves to cook and heat up food. This spectrum goes from radio waves to microwaves, to infra-red, visible light, ultraviolet, and x-rays. When you press the start button your oven fires microwaves at the food. The microwaves make the water molecules vibrate back and forth which creates heat and heat cooks your food. Microwaves are set to the perfect amount of microwaves so it doesn't make the water molecules vibrate to much to melt plastic or metal. I think that this is a very interesting process that I only knew part about. I also think that it should be more complicated than the process stated above but it's not.

  • RachelBi
    5/30/2014 - 05:37 p.m.

    When I took my family consumer science class, they taught us all about how microwaves are used to cook food. Its a neat process.

    6/03/2014 - 10:56 p.m.

    Its ironic isn't it the average person uses a microwave at least one a week but has no idea how it works. That is how it goes with most technology such as the internet you use it but do you really understand it. If more people know how you use the devices in there home there would be much less problems.

  • hunter.mellinger64
    2/27/2015 - 01:02 p.m.

    The person who invented the microwave was named was Percy Spencer and his invention was an accident! Spencer worked for a company named Raytheon, developing microwave radar transmitters during World war 2
    One day in 1945, he noticed that a candy bar he had in his pocket was starting to melt. The microwaves from the radar set he was working on were cooking the candy bar in his pocket!
    With a little experimentation, Spencer figured out that the microwaves could be concentrated to heat food. He created the first working microwave oven, and the first food he cooked in it was popcorn.

  • Haley Patterson
    3/23/2015 - 01:47 p.m.

    This is another thing that I never really thought about. It's very interesting the things humans can make and just putting food inside a box and hitting some buttons to heat up your food is something extraordinary.