Invention of Microwave

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By accident, several years before,two scientists invented the magnetron, a tube that produces microwaves.

Installing magnetrons in Britain抯 radar system, the microwaves were able to spot Nazi warplanes on their way

to bomb the British Isles. It was discovered that microwaves also cook food. Called the Radar Range, the first

microwave oven to go on the market was roughly as large and heavy as a refrigerator.

The idea of using microwave energy to cook food was accidentally discovered by Percy LeBaron Spencer of the

Raytheon Company when he found that radar waves had melted a candy bar in his pocket. Experiments showed

that microwave heating could raise the internal temperature of many foods far more rapidly than a

conventional oven.

In 1967, Amana, a division of Raytheon, introduced its domestic Radarange microwave oven, marking the

beginning of the use of microwave ovens in home kitchens. Although sales were slow during the first few years,

partially due to the oven抯 relatively expensive price tag, the concept of quick microwave cooking had arrived.

In succeeding years, Litton and a number of other companies joined the countertop microwave oven market.

By the end of 1971, the price of countertop units began to decrease and their capabilities were expanded.

The heating of the microwave is through the process called radiation and conduction. Conduction is the process

by which thermal energy is transmitted through a medium from one particle to another. The conduction took

place in the metal tray of the microwave. Conduction of thermal energy in metals is far better than in other solids.

This is because conduction takes place through vibrationg molecules as well as the free electrons in meatals.

When heated, the free electrons gain energy and moves faster. These electrons are free to travel in the spaces

between the molecules before colliding with other electrons and molecules and transferring some of their

energy to them. This process is much faster than the conduction by vibration of the molecules in the body.

Radiation is another kind of heating process, it is the transfer of thermal energy by electromagnetic waves.

For example of radiation is energy reaches us from the Sun. As there is a vacum between Earth and Sun. The Sun's

energy travels to Earth as electromagnetic waves at the speed of light. Just like the vacum spaces between the

heating source and the food.