Over the years application of modern technology in the domestic sphere has made our lives more comfortable and easier. Washing machines, vacuum cleaners, microwave ovens etc. are a few examples that meet the demands of the modern society of today. The new gifts of technology especially for household use, always generate a curiosity in us about their working principles. Now let us discuss how does a microwave oven work?
A microwave oven does not have burning flames or red-hot plates like gas and electric cookers. Its operational mechanism is simple. The user puts the food into a metal box and presses a switch. Inside the box, invisible energy rays bombard the food.
The oven gets its name from the rays that cook the food – the rays are called microwaves. Microwaves are part of the spectrum of electromagnetic waves which includes light waves and X-rays. They have wavelengths from about 30cms to one millimetre which places them between the shortest radio waves and infra-red waves. One of their properties is to excite molecules, especially in liquids, and make them vibrate and heat up. For this reason, food with a large proportion of water gets cooked very quickly.
The source of microwaves in the oven is a magnetron. It is a two-electrode valve for generating high-frequency oscillations. Microwaves generated by the magnetron travel down a metal-duct and are scattered around by a metal fan for a more even cooking. The molecules rub against each other and the friction produces heat. The water then gets heated up and consequently the food gets cooked quickly.
Microwave ovens are a potentially dangerous source of radiation. For this reason the ovens are metal lined and have strong doors. The oven will not function until the doors are closed thus ensuring safety. Most modern ovens contain small computers that automatically cook the food at the appropriate temperature for the right length of time. Microwave ovens are preferred and widely used in restaurants, hotels etc. where quick service is important.