Table of contents:
- Cooked steak and potatoes between metal plates
- Microwave property discovered by accident
- Microwave oven for the restaurant
- Inexpensive microwave ovens have led to popularity
Video: The Development Of The Microwave Oven
2023 Author: Hannah Pearcy | [email protected]. Last modified: 2023-05-24 11:12
The use of radio frequency radio waves to heat materials was made possible by the development of vacuum tube radio transmitters around 1920. Until 1930, this effect was used medically for heat therapy on the human body.
Cooked steak and potatoes between metal plates
At the 1933 Chicago World's Fair, food cooking was demonstrated between two metal plates attached to a 10 kW, 60 MHz shortwave transmitter. Steaks and potatoes could be cooked within minutes. However, this experimental setup was not exactly energy-efficient, since the dielectric heating - depending on the near-field effect - was extremely small in relation to the wavelength.
Microwave property discovered by accident
It was not until the invention of the magnetron, a cavity resonator, that electromagnetic waves with a sufficiently small wavelength - so-called microwaves - could be generated. The magnetron was originally a key component in the development of shortwave radar during World War II.
It was only by chance that it was discovered in 1945 that a heating effect can also be achieved with this microwave. A Raytheon employee noticed that the microwaves of an active radar device he was working on melted a chocolate bar in his pocket. To verify his result, the employee created a high-density electromagnetic field by injecting microwave energy from a magnetron into a metal box from which there was no way to escape. When the food was placed in the box with the microwave energy, the temperature rose rapidly.
Microwave oven for the restaurant
The first food to be cooked in a microwave was popcorn - a coveted microwave dish to this day. The second attempt started with a raw egg, but it soon became apparent that eggs in the microwave were not a good idea.
On October 8, 1945, Raytheon filed a patent for the microwave cooking process. An oven that heated food with the microwave energy of a magnetron was soon installed in a Boston restaurant for testing.
Two years later, the company sold the first commercially available microwave oven. It was almost 1.8 meters high, weighed 340 kilograms, and was about $ 5,000 at the time (equivalent to about $ 57,000 today). The stove had 3 kW of power, about three times as much as today's microwave ovens, and was water-cooled.
Inexpensive microwave ovens have led to popularity
From the late 1970s, Japanese companies began producing cheap microwave ovens that were affordable for home use, which led to a rapid expansion of the microwave oven market in the 1980s. After Japanese dominance during much of the 1980s, South Korean manufacturers began to enter the market in the late 1980s, with Samsung becoming a major microwave manufacturer.
The microwave quickly became the basic equipment of almost every kitchen: in 1971 only one percent of all American households had a microwave, in 1986 it was one in four and in 1997 over 90 percent of households. Microwaves are still popular in Germany: in 2019, around 73 percent of households had a microwave.