Skip to Content

Melted Chocolate to Microwave

An imaginative engineer turned a mess into a universal machine.

If you live in the United States, odds are a machine much like those stacked on the right rests on a kitchen countertop in your home. If so, your microwave is a descendant of the device on the right. This is the first microwave oven, built by Massachusetts-based Raytheon in 1947; it operated for three decades in the kitchen of one of Raytheon’s founders. Raytheon named the original microwave the “Radarange” because it cooked food using the same radio-wave-producing magnetron tubes that the company manufactured for use in military radar.

Raytheon credits the discovery of microwave cooking to a grade-school-educated engineer named Percy L. Spencer. One day in 1945, Spencer was walking through a radar test room with a chocolate bar in his pocket; he came too close to a running magnetron tube and the candy began to melt.

Spencer was already known at the company for his curiosity and ingenuity, and he reacted true to form-he pointed the magnetron at kernels of corn and watched them pop, aimed for an egg and saw it cook so quickly it exploded. Soon, Raytheon officers were sampling microwaved meals in the executive dining room and within a few years the company was marketing the Radarange for $2,000 to $3,000.

At that price, the Radarange was primarily a commercial cooker, providing warm meals on trains and ocean liners, and in restaurants and hotel dining rooms; some establishments offered special all-microwaved meals to promote the new technology. Early efforts to sell home machines through a licensing agreement with the Tappan Stove Co. were unsuccessful. But in 1963, a chance dinner meeting between two Raytheon executives and the president of Amana Refrigeration, Inc., all visiting Chicago, resulted in the sale of Amana to Raytheon. Raytheon capitalized on Amana’s experience in marketing and distributing consumer goods, and in 1967 introduced the under-$500 countertop Amana Home Radarange.

Today, 90 percent of American homes have microwave ovens. And though Spencer never profited from his patent on the device, his early snack experiments were prophetic; many of us use our microwaves most often to pop popcorn and, some pastry chefs argue, a few seconds in the microwave is simply the best way to melt chocolate.

Keep Reading

Most Popular

Conceptual illustration of a therapy session
Conceptual illustration of a therapy session

The therapists using AI to make therapy better

Researchers are learning more about how therapy works by examining the language therapists use with clients. It could lead to more people getting better, and staying better.

street in Kabul at night
street in Kabul at night

Can Afghanistan’s underground “sneakernet” survive the Taliban?

A once-thriving network of merchants selling digital content to people without internet connections is struggling under Taliban rule.

Conceptual illustration showing a file folder with the China flag and various papers flying out of it
Conceptual illustration showing a file folder with the China flag and various papers flying out of it

The US crackdown on Chinese economic espionage is a mess. We have the data to show it.

The US government’s China Initiative sought to protect national security. In the most comprehensive analysis of cases to date, MIT Technology Review reveals how far it has strayed from its goals.

IBM engineers at Ames Research Center
IBM engineers at Ames Research Center

Where computing might go next

The future of computing depends in part on how we reckon with its past.

Stay connected

Illustration by Rose WongIllustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.