This history really cooks!

January 24, 2010

Another anniversary worth noting.

On January 24, 1950, the U.S. Patent Office awarded Percy L. Stevens patent # 2,495,429, for his “Method of Treating Foodstuffs” with waves from a magnetron oscillator.  Sixty years ago today Percy Stevens changed culinary life forever.

You guessed it:  The microwave oven.

Microwave oven patent Percy L Stevens - US2495429 (drawing only)

Patent for "Method for Treating Foodstuffs," granted January 24, 1950, to Percy L. Stevens of the Raytheon Corp. - the microwave oven. Image via FreePatentsOnline.com

On CBS “Sunday Morning” Charles Osgood said that in 1975 microwave oven sales surpassed conventional oven sales for the first time.  This is more remarkable because the first commercial microwave in 1955 was too big for home kitchens, and at $1,300, too pricey.  Japanese modifications of the magnetron to shrink it made microwave ovens much like those we have today ready for the market for the first time in 1967.  Eight years from market entry to majority of the market.

It only makes sense:  Today offices on every floor of every office building have microwave ovens in their break rooms, but almost none ever had conventional ovens.  College students have microwaves in their dormitory rooms.  Even gasoline stations offer foods for microwaving by customers.

Spencer’s invention makes it possible to heat foods quickly with a relatively small device, in thousands of places where no conventional oven would work well, or be welcomed.

According to legend — accurate? — Spencer got the idea after working with magnetron tubes while carrying a chocolate bar in his pocket.  He noticed the chocolate bar melted.  Within a short time he had demonstrated the ability to pop popcorn and burst an egg with the microwaves from the tube.

Sign of the changing times:  Many children today do not know how to pop popcorn without a microwave.  Legend has it that children in elementary school ask where the Massachusetts natives kept the microwaves with which they popped the corn that delighted the settlers of the Plymouth Colony.

Microwave oven inventor Percy Stevens with early microwave equipment at Raytheon

Microwave oven inventor Percy Spencer with early microwave equipment at Raytheon - photo from Spencer family archive

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Forgotten anniversaries: Microwave oven patent

January 26, 2009

Some history really does need to be rewarmed.

January 24 marks the anniversary of the granting of the patent for the microwave oven, “Method of treating foodstuffs.” Do your texts even refer to this by-product of World War II?  What benefits of microwave ovens can your students come up with?  Will they offer the apocryphal question about how Native Americans could possibly have invented popcorn with their wood-fired microwave ovens?

Dr. Percy L. Spencer noted that a chocolate bar in his shirt pocket had melted when he was working around an operating radar tube, at Raytheon Corp., during World War II (the patent application for microwave cooking was filed on October 8, 1945).  With a little experimentation, he determined the microwaves from the radar tube were rapidly cooking things — think exploding egg, think popping corn.

Drawing from the patent of the microwave oven, granted to Percy L. Spencer on January 24, 1950; courtesy the Southwest Museum of Engineering, Communications and Computation

Drawing from the patent of the microwave oven, granted to Percy L. Spencer on January 24, 1950; courtesy the Southwest Museum of Engineering, Communications and Computation

One of the problems Spencer had to overcome was that radar tubes cooked foods way too fast.  He had to tune the magnetron tubes to produce wavelengths with less energy, to heat food more slowly so the cooking could be controlled.  Spencer explained this process of invention in the first page of text on the patent itself.

Perhaps one could create an interesting DBQ with only patents, tracing radio and radar through the microwave oven.

This is one device you probably can demonstrate  safely  in any history classroom.

Resources:

Tip of the old scrub brush to Rhapsody in Book’s Weblog.


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