June 8

When Was the Microwave Invented? | The Accidental Invention Explained


Author: Ana Stanar
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You probably didn't know that microwave ovens were invented years ago; by accident. Most American households have microwave ovens because it's convenient and perfectly does the job. The UK made the cavity magnetron which emitted enough magnetic waves and was sufficient ground for the development of the modern microwave.

The modern microwave oven was invented in 1946 by a Raytheon researcher called Percy. Percy introduced modern microwave technology and filled for the use of microwaves to cook and heat food. Currently, microwaves are used for professional cooking since microwaves don't produce occasional flavors produced by other cooking methods. This article describes the historical development and progress of the microwave oven. In addition, check out the best retro microwave ovens that carry some of the old charm.

Who Invented the Microwave Oven?

The Raytheon researcher; Percy Spencer discovered the connection between the magnetron and heating by accident. Percy LeBaron's Spencer worked on an active radar set a few years later, accidentally melting a chocolate bar in his pocket. He thought microwaves could cook food. Spencer then tried popcorn and made a microwave egg. By 1945, Raytheon had filed a microwave cooking patent.

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The microwave oven used for heating food bombards food with microwaves that make dipole molecules of water and other substances revolve and collide rapidly, manifesting as heat.

Microwave ovens uniformly and quickly heat foods. Microwave History states; Microwave oven was invented by accident or not because there were people who already knew what microwaves could do. However, only one man asked himself what he can do with these microwaves and how they can serve. That man is Percy.

Percy Spencer, Who Is He?

Spencer was a self-taught engineer with a passion for manufacturing items that solved daily personal problems.

He desired to advance things with a mentality that there were no challenging things and that every challenge was a problem. 

Spencer grew up surrounded by mechanics and didn't acquire formal education because he grew up in the Howland, Maine wilderness.


However, he started engineering because of curiosity.  At 12 through fourteen, Spencer worked at the spool mill and got hired for electricity installation in a paper mill. Later, inspired by the titanic heroic radio operations, Spencer enrolled in the Navy. In the Navy, he learned technology through textbooks while he stood to watch. 

Spencer got hired after world war two ended at the American appliance company that Vannevar Bush had recently developed. Vannevar Bush is currently renowned for predicting internet and computer innovations plus managing the Manhattan project. In nineteen-twenty-five, the company changed its name to Raytheon Manufacturing Company. The company still stands and currently manufactures electronic war materials, systems for military training, plus missiles.

In his twenties, Spencer became the most valued engineer, and he was popularly known. For allied forces during world war two, Spencer solved many problems. For instance, he made proximity fuses that allow you to trigger explosive artillery shells while in the air before landing on the target. Out of all these, we see Spence with a spark to solve mechanical difficulties.

The Accidental Invention of The Microwave Oven Radarange

Percy Spencer developed 'Radarange,' the first microwave oven, during World War 2 in October 1945 to replace magnetron tubes used by soldier's short-range military radars. The microwave oven project didn't begin with Percy Spencer initially. Back at the time, it was ideological; heating food through radio waves among different firms like General Electric, Bell Labs, RCA, etcetera worked on that technology variations.


However, during the 1933 world's fair held in Chicago, Westinghouse's 10-kilowatt shortwave radio transmitter got demonstrated, and from it, Percy Spence advanced the technology to develop Radarange. To his surprise, he accidentally discovered microwave ovens could heat and cook food.

Therefore, the microwave oven, shortened as microwave, didn't come from humble beginnings. Instead, it’s an electric oven appliance born of the radar systems used in World War 2. The device cooks and heats food through electromagnetic radiation and microwave frequency waves. Their radiations induce food's polar molecules to rotate and produce thermal-kinetic energy through the dielectric heating process.

Strategical Historical Steps Towards the Development of Microwave Ovens

Early Developments Plus Cavity Magnetron Before/During World War II

In the 1920s, the development of vacuum tube radio transmitters made possible treatment of tissue through high-frequency radio waves. During the nineteen-thirty Chicago fair, Westinghouse demonstrated cooking foods through the two-plate shortwave transmitter.

Later, the cavity magnetron, a vacuum tube generating high-power microwaves through electron and magnetic field interaction, demonstrated the possibility of producing short microwave strength emissions. Finally, Percy, an engineer From Howland, accidentally discovered the healing power of the heating microwave beam power.

blue circles

Percy created a magnetic field with high density by connecting the microwaves from the magnetron to a metal box without losing any waves. When he placed food in the box, its temperature raised rapidly. In October that year, he applied for a patent from the government allowing for his microwave's cooking process.

How the Cavity Magnetrons Works?

Sir John Turton Randall, FRSE, built the first multi-cavity magnetron in conjunction with co-workers for the American and British radar installations during World War II. In 1940, Harry boot manufactured the prototype for working, containing a valve producing microwave radio pulses with a 10cm-wavelength.

The magnetron works by regulating electromagnetic waves’ emission through vibrations. This device works like whistles, whereby instead of controlling sound vibrations, it holds magnetic pulses. While adjusting the level of magnetron tube’s power level, Spencer accidentally discovered the microwave heating capacity therein.


How Magnetic Oven Technology Accidentally Happened?

The story handed down over the years has changed because some who tell it describe a melted chocolate bar leading to Percy's eureka. Chocolates have a lower melting point compared to peanuts, hence the surprise.

Having lived in Maine, Spencer would always carry around in his pocket a peanut cluster around lunchtime to feed squirrels and chipmunks since he loved them. So when he was adjusting, trying to focus more microwave power through the magnetron, Spencer used the peanuts to try out the 1933 Chicago food cooking project that cooked potatoes superfast. He increased the magnetic field wavelength from the magnetron, peanuts rapidly increased the temperature, and they melted.

Best retro microwave ovens

Understandingly curious about what happened, Spencer runs a second test using an egg under the magnetron tube. After some time, the microwaved egg exploded and splattered all over Spencer's face. The next day, Percy used corn kernels and cooked them through his new invention and shared the popcorn with fellow workers without assurance of microwave radiation safety.

When Was the Microwave Available to The Public?

The patent went through, and in a Boston restaurant, the magnetron got tested. Then, Raytheon introduced the first  Radarange commercial microwave oven and advertised it for sale. It cost five thousand dollars, equivalent to the current $58K. This microwave oven weighed three-forty kilograms and was water-cooled.

Later, Raytheon sold the technology to different companies like Tappan, who further developed microwave development. Finally, in 1961, the Sharp Corporation started producing microwave ovens and introduced its first ovens with a turntable to promote heating.

microwave on sale

During that time, Raytheon sought to expand their Radarange tech, availing it to home markets; therefore, they acquired Amana to enhance their manufacturing capability. In nineteen-sixty-seven, Raytheon introduced countertop Amana Radarange at a lower price of $495, equivalent to $4000 today. The technology was different from Sharps because the countertop motor stirrer rotated while the food remained stationary.

How Much Did A Microwave Cost In 1975?

In 1975, only four percent of American households owned microwave ovens. At this time, the majority of homesteads had dishwashers because the technology was outstanding back then. However, remember Raytheon had acquired Amana and made cheaper and appealing Radarange models.

The price ranged depending on which brand you chose. The Raytheon model costs roughly $500, while the Sharp corporation microwave ovens cost approximately $1200. To put that into context, a perfectly fine microwave oven these days, as reviewed here, goes for under $200, or under $150, according to this review.

jar full of money

Over the next year, microwave tech spread out to sixteen percent of households in America. Over the years, nearly all homes now possess a microwave oven; 90 percent of American families have microwave ovens.

Microwave Oven; Safety

Since their development, microwaves have had a terrible reputation because of microwave radiation. The World Health Organization (WHO) says microwaves remain safe provided you properly and maintain them. Massive microwave radiations are cancerous and harmful, but their designs ensure the radiations come when you shut your door and turn on the microwave.

WHO states that several nations and international committees have established 50 watts per meter square emission to ensure safety. Plus, stay distanced from external services. Also, radiation exposure reduces with distance while using microwaves. Also, be cautious with microwave-cooked foods because they cook unevenly with some extremely hot portions while others get undercooked.

How to Measure Cubic Feet of Microwave

Microwave Ovens Future

Modern microwaves have auto-stop sensors when food completes cooking. In addition, some companies like Samsung develop microwaves containing different cooking methods; defrosting meat, frying plus backing, fermentation for making fresh yogurt and dough, and reheating leftovers.

NXP semiconductors microwave ovens use radiofrequency energy to cook, controlling the power amounts to each food part, improving nutrition and taste, consistency and efficiency. At the same time, other ovens are solar chargeable and contain incorporated lines.

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The home microwave oven has radicalized our kitchens, saving time and assuring fast microwave cooking. However, though it is shielded for your safety, microwaves still emit insignificant radiations that may affect your Bluetooth and Wi-Fi, plus other devices using 2.45 GHz wavebands.

It is best to maintain a safe distance when you turn your microwave on to avoid potential harm caused by minor microwave radiations.

About the author

Ana Stanar

An Art Teacher, entrepreneur, and a mother of three, Ana considers cooking a form of art - pleasure for all senses as well as a process that requires creativity, passion and devotion. Since she leads a busy life, Ana just loves testing various kitchen appliances for Kitchen Gearoid, especially those that save her time while preparing food and cooking but also make every meal a masterpiece!


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