Wonder Contributors

Thanks to Bob from Austin, Texas, for suggesting we revisit this Wonder! Thanks for WONDERing with us, Bob!

When your tummy is rumbling, there’s one kitchen appliance that can quickly stop the grumbling. From reheating leftover pizza to popping up some light and fluffy popcorn, there’s one device that gets the job done in a jiffy. What are we talking about? The microwave oven, of course!

You know the drill. You put your leftovers on a microwave-safe plate, pop it into the microwave, hit a few buttons, and like magic, it’s warm and ready to eat. And all this takes place in a few seconds rather than the minutes or hours that the stove and oven can take.

Who was the genius who invented this wonderful creation? As a matter of fact, his name was Percy Spencer and his invention was an accident! Spencer worked for a company named Raytheon, developing microwave radar transmitters during World War II.

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.

Microwave ovens use microwaves, which are radio waves at a frequency of approximately 2,500 megahertz, to heat food. Microwaves are absorbed by water, fats and sugars and are immediately converted to heat. The microwaves penetrate food quickly, so they cook food evenly and quickly.

Microwaves are not absorbed by most plastics, glass or ceramics, so they are perfect for heating food without heating everything else around the food. This enables microwave ovens to use less energy than other cooking appliances.

Raytheon filed a patent for Spencer’s microwave cooking process on October 8, 1945. In 1947, Raytheon produced the first commercial microwave oven and called it the “Radarange.” Would you believe it was almost six feet tall and weighed about 750 pounds? It’s true!

It was also expensive. The first Radarange was $5,000, which would be equal to over $52,000 today. It would be many years before microwave ovens could be produced and sold inexpensively.

Today, millions of kitchens contain a microwave oven. You’ll also find them in just about every restaurant kitchen and quite a few convenience stores, too. Whether you’re heating up water for coffee, reheating leftovers for lunch or popping a bag of microwave popcorn for a late-night snack, the microwave oven does these things quicker than any other appliance. And that’s why it’s so popular!

56 Join the Discussion

1 Star2 Stars3 Stars4 Stars5 Stars  (45 votes, avg. 4.22 out of 5)
    • We’re so excited that you learned something new today, Danny! It’s cool when we learn that the great things we use every day were an accidental invention! Thanks for joining us today and sharing your marvelous Wonder guess! :)

  1. I thought today’s wonder was really cool since Percy Spencer made it on accident.

    I think tomorrow’s wonder will be a bed or giraffe.

    • WOHOO, we’re excited that Wondergirl101 is here today! Thanks for sharing your comment about Percy Spencer’s accidental invention! We’re so glad that you’re WONDERing with us about cool inventions! Have a SUPER day– we’ll see you soon! :)

  2. Hi! Sorry I was busy.


    1 What do you cook in your microwave?

    2 Who invented the microwave?

    3 What microwave do you have!?

    There are the questions!

    • Welcome back, Laserdudle! We are excited that you’re WONDERing with us today! We Wonder if you can answer those questions on your own after checking out today’s Wonder! Keep up the great work! :)

  3. Jaedyn thinks the most interesting thing we learned was that the first microwave oven was 6 feet tall!

    Shanaya wonders what materials Spencer used to build the first microwave oven.

    For tomorrow’s Wonder, Kamron thinks it might be a car. Daevon thinks it might be a net.

    We can’t wait to find out!

    • HOORAY, we’re excited that our Wonder Friends, the Third Grade All-Stars, are WONDERing with us on this fantastic Friday! We’re excited that you are all WONDERing on your own about the microwave oven– it’s come a long way!

      We agree, Jaedyn, it’s interesting to imagine a 6 foot tall microwave in your house! And we’re excited that Shanaya is curious about those original materials. We aren’t certain, but we bet it was very similar to an actual oven!

      Thanks for guessing our Wonder tomorrow, Kamron and Daevon! We can’t wait to see you soon! :)

    • Thanks for sharing your comment, Trsta! We really appreciate your thoughts, and although this Wonder may not have been your favorite, we’re glad you’ve been WONDERing with us! :)

    • WOW, what a great guess! We Wonder if you have done some WONDERing of your own, Trista? We can’t wait to find out what tomorrow’s Wonder will bring… but we’re excited! :)

    • We are proud to say that our Wonder Friends do an excellent job of researching our Wonders, so the information is great! We hope you have a SUPER day, Wondergirl102! :)

    • We bet it looks a LOT different than it did originally, AnnaBella! We can only imagine what it would be like to have a 6 foot microwave in our house today! We sure are glad that we can heat our food quickly without a gigantic appliance today! :)

  4. We thought today’s wonder was interesting because of how huge the first microwaves were.

    We think tomorrow’s wonder will be about an avalanche, hoarders, spiderwebs, boulders, giant hamster balls, bulldozers, or some kind of machines.

    • HOORAY, Mrs. Ski’s AM Class is here! What a happy Friday indeed!

      Can you imagine such a large appliance in your house? It would look more like an oven stacked on top of another oven! YIKES! We’re glad that microwaves today are smaller and quicker than the originals!

      Thanks for sharing your very awesome guesses for tomorrow’s Wonder– we can’t wait to see you soon! :)

  5. Cool! I think it’s awesome how most inventions were created by accident. :) It’s totallysuperawesome!!!! Thanks!
    :) :D ;) :( :P

    • HOORAY, we LOVE your enthusiasm, Bryleigh! We sure are glad that the microwave was invented– even if it was by accident! Have a terrific day, Wonder Friend! We’re glad you’re here! :)

  6. This is a great wonder!!! I never knew the microwave was invented by accident. Thanks for this great information today.

    • Hooray, we’re excited that our Wonder Friend, Ms. Blanchard, learned something new today! We LOVE WONDERing with great friends like you! Thanks for spreading the Wonder and sharing your comment! Have a SUPER weekend! :)

  7. What was in the microwave? It looked like a stick of butter, but butter would have melted, and the stuff in the video puffed up like an exploding storm cloud. Was it marshmallows?

    • Hey there, Mystery! What great guesses you have about tomorrow’s Wonder! We can’t wait to find out what it will be, but it’s going to be SUPER! Have a great day! :)

  8. This article was so crazy. I can’t believe microwave ovens were that expensive and big back then. It must have been really hard to use one. I think tomorrow’s wonder is about riptides.

    • Isn’t it amazing to imagine inventing something by accident, Jacob L?! We think it’s pretty crazy to imagine how much a microwave would have cost many years ago? Thank you for sharing your AWESOME guess for tomorrow’s Wonder, too! :)

    • You make a great point, Gina M! We really have learned about a lot of different accidental inventions! We are glad you pointed that out, and we hope you have a GREAT day! :)

    • We really appreciate the great things that a microwave can do, too, Bilbo! We’re glad you stopped by Wonderopolis today to say hello! :)

  9. Wow! That was so cool!! A bar of soap! And he didn’t mean to. Why did he put a bar of soap in there? I so liked today’s wonder!!! :p

    • YAY, we’re glad that you were impressed by that bar of soap in the microwave, Blakeleigh! We bet the person in the video knew that the bar was going to foam up in the microwave– how crazy! Thanks for joining us at Wonderopolis today! :)

    • WOHOO, we’re glad our Wonder Friend Yeniffer is WONDERing with us today! Can you believe the microwave was invented by accident?! Hope to see you tomorrow for a new and rolling Wonder! :)

  10. Wow I did not know that soap can do that in the microwave. I won’t to try it in my house but with a different object maybe tofu.

    • Isn’t it fascinating, Fatumata?? We learned that the microwave is a pretty powerful invention… and we are glad it was invented, even if it happened by accident! Thanks for WONDERing on your own– make sure you are safe and talk to an adult or parent before trying your very own microwave experiments! :)

    • We learned that Percy Spencer is the inventor of the microwave, Queen Panda! We Wonder if you can read the rest of the Wonder to find out how the invention came to be! :)

  11. So many great inventions were created by accident, did you know the telephone was created by accident too?! By the way, I was just studying microwaves and I saw this wonderful wonder. I am a big Harry potter fan,are you?

    • Hey there, Harry Potter! Thanks for sharing your comment today! We are so glad you enjoyed this Wonder and you made an awesome connection to the microwave, too! We’re glad you told us about what you learned– we dont’ know what we would do without the telephone! :)

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Have you ever wondered…

  • Who invented the microwave oven?
  • How does a microwave oven work?
  • What was the first microwave oven like?

Wonder Gallery

microwave_shutterstock_85154995microwave-1microwave-2microwave-3Vimeo Video

Try It Out

We hope today’s Wonder of the Day made you feel all warm inside! Keep the learning going by checking out one or more of the following activities with a friend or family member:

  • How common are microwave ovens today? Find out! Make a list of all the places you can find a microwave oven over the course of the next week. Is there one (or more than one) at school? What about where your parents work? Friends’ houses? Convenience stores? Restaurants? Ask a friend to do the same thing and see who can find the most microwave ovens in one week.
  • How much more quickly can a microwave oven cook a product than a conventional oven? Take a trip to the grocery store with an adult. Head to the frozen food aisle and find some example foods that can be cooked in either a microwave or conventional oven. Compare the cooking times for each method. Do the cooking times vary depending upon the type of food? Use a calculator to calculate examples of percentages for how much faster a microwave oven can be.
  • Do you use a microwave oven in your kitchen at home? Here are some fun, easy recipes you can make with a microwave oven. Choose a recipe or two to try and then check the list of ingredients. You may need to make a trip to the store before you begin. Be sure to get help from a friend or family member!

Still Wondering

Science NetLinks’ Technology at Home site lets you go back through the twentieth century to find out when everyday items, such as computers, TVs and microwave ovens, first appeared in homes.

Test Your Knowledge

Wonder What’s Next?

Despite its name, no felines were involved in the creation of tomorrow’s Wonder of the Day!

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