Is Microwave Oven An Accidental Invention?

As we know, microwave ovens are used for heating or cooking food. We bake or heat food using a microwave oven which uses electromagnetic radiation to heat food. The microwaves radiations are reflected by metals, they are absorbed by food and they pass through plastic, glass, paper etc. These properties of microwaves make it suitable for cooking.

Do You Know How A Microwave Oven Was Invented?

American engineer Percy Spencer accidentally invented the microwave application for cooking. He was experimenting on magnetron, a vacuum tube in which flow of electrons are controlled by an applied magnetic field at microwave frequencies. During his experiment he found that a chocolate in his pocket melted.Then Percy Spencer tested with egg and popcorn. He noticed that the egg exploded and popcorn popped. Spencer understood that microwaves can cook food faster than conventional heating and he filed a patent in 1945 for the invention of the microwave oven .

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The first commercially available microwave oven was developed in 1947 by Raytheon and named as Radarange. It weighed 340 Kg and 1.8m in height. Radarange consumed a power of 3 Kilowatts which is much higher compared to the new microwave oven used in house. The microwave oven price was nearly USD 5000 that would currently (in 2022) cost 3.98 lakh Indian rupees. Later in the 1960s and 1970s different home models of microwave ovens came to the market. Now the microwave oven is used world wide. The microwave oven used for household applications now consumes a power of 1200 watts or 1.2 Kilowatts and microwave oven prices are below INR 10,000.

Microwave Frequency

Microwaves are electromagnetic radiation whose frequency ranges from 300MHz to 300 GHz. Microwaves are non ionizing electromagnetic waves, so they do not change the composition of molecules. The working frequency of household microwave ovens is 2450MHz and for industrial applications the frequencies used are between 945MHz and 2450MHz.

How Does A Microwave Oven Work

The Ac supply voltage is converted to low voltage Ac and high voltage Dc for working of magnetrons. The microwaves inside the oven are produced by magnetrons. The microwaves produced reflect the metallic surface of the microwave oven and causes the water molecules in the food to vibrate. The vibration of the molecules increases the friction between them and produces heat, which cooks the food. Microwaves cook food from the outer layer to inside. First outer layer is heated and by conduction the inner layers are heated.

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Metal plates are not used in microwave ovens as they reflect microwaves off and food is not cooked properly and may damage the oven also. Usually glass, ceramic and certain plastic plates or bowls are used in the microwave oven. Some plastics are not suitable as they melt due to the heat.

Read the instruction booklet given while purchasing to know what kind of plates or bowls are suitable for cooking in a microwave oven. Household microwave ovens are small in size and they cannot be used to cook food in large quantities. If leakage occurs, longer exposure to microwave ovens may cause burn to skin, this is the main health risk of microwave ovens.