The Incredible Tale of Inventing the Microwave Oven

Ahhh the microwave oven: perhaps the most con of mod cons. Whether you’re zapping a mug of lukewarm coffee back to life, rewarming some leftovers, or heating up a frozen burrito for the fourth time this week, this handy little device will get the job done quickly and efficiently without the muss and fuss of a regular stove or oven. But have you ever wondered how this seemingly magical box manages to cook your food without flames or heat – or who invented it in the first place and why? Well, the answer may surprise you, for the key working component in this appliance found in every kitchen, break room, and hotel suite was once the most closely-guarded military secret in the world, a key technological breakthrough that was instrumental in winning the Second World War and shaping the modern world as we know it. This is the long and surprisingly fascinating story of the microwave oven. The origins of the microwave oven stretch all the way back to the discovery of radio waves. In 1865, Scottish physicist James Clerk Maxwell published the groundbreaking paper A Dynamical Theory of Electromagnetic Fields, in which he postulated that visible light is composed of interacting electric and magnetic fields and laid out the physical laws – today known as Maxwell’s Equations – governing the behaviour of these waves. Maxwell’s theories predicted the existence of an entire spectrum of electromagnetic waves, varying in frequency and wavelength. In 1888, German physicist Heinrich Hertz – whose name is now the official unit of frequency – succeeded in generating and detecting long, low-frequency electromagnetic waves, confirming Maxwell’s predictions. Hertz’s discoveries not only inspired later inventors like Guglielmo Marconi to develop wireless communications – aka radio – but also laid the groundwork for the discovery of the rest of the electromagnetic spectrum. While the spectrum is continuous, for the sake of convenience it is usually divided into seven main regions or bands according to wavelength: radio waves down to 10 metres; microwaves, from 1 metre to 1 millimetre; infrared light, from 100 to 1 micrometers; visible light, from 700 to 400 nanometers; ultraviolet light, from 400 to 121 nanometers; X-rays, from 10 nanometers to 100 picometer; and finally gamma rays, 10 picometers and below. In the 1910s and 20s, it was discovered that high-frequency electric currents and shortwave radio signals could induce heating in a variety of materials – including human tissue. This led to the development of diathermy, a method for electromagnetically heating muscles and other deep tissue still widely used in physiotherapy to this day. The application of this technology to the field of cooking was readily apparent, and at the 1933 Century of Progress Exhibition in Chicago, electrical giant Westinghouse demonstrated the rapid cooking of foods like steak and potatoes by placing them between two metal plates attached to a 10 kilowatt, 60 megahertz shortwave radio transmitter. But while impressive, the required equipment was bulky, expensive, and dangerous, and the technique failed to take off. The dream of cooking food rapidly without flames would have to await the development of a revolutionary piece of technology, whose invention was driven by the needs not of medicine or gastronomy, but of war... This is an abridged version of a video on our channel TodayIFoundOut which you can check out and subscribe to here:    / @todayifoundout