“The Microwave Oven”

HOW IT WORKS:First and foremost, we need to define what a microwave is; this will enable us to understand better what we are talking about.The word or rather term “microwave” has lots of applications.It is used in the telecommunication industry as well as in the domestic or home environment; these are not the only applications, it may also be used in medical or many other specialised or non-specialised environs. A microwave might be defined as an Electromagnetic wave that has a frequency ranging from a metre down to a millimetre. Long before the home application of Microwaves, these were basically used in the transmission of radio signals from one point to another through the air. Even up to now, many communication companies still use the Microwave stations for both Data and voice transmission, though the advent of the Optical fibre is rapidly changing the applicability of the microwave in this industry. Back to the Domestic applicability of the same, the Microwave Oven is a device that has taken root in the kitchens of many developed and developing countries. It is a darling of many urbanites, reason; it is a “compatriot” of the refrigerator! With increased scarcity of time, modern life is dictating that, people spend more time working and less preparing food. These days, people prepare food and store it in the refrigerator or even deep freezer, from here; they extract small quantities which they consume as and when the need arises. In order to save time, such food must be warmed up or heated within the shortest possible time; this renders the Microwave oven to become the most suitable device for such a purpose. A microwave oven consists of the following, a high voltage transformer which passes energy to the magnetron, a cavity magnetron which converts high-voltage electric energy to microwave radiation, a magnetron control circuit (usually with a microcontroller), a waveguide and a cooking chamber. A microwave oven works by passing non-ionizing microwave radiation, usually at a frequency of 2.45 GHz (a wavelength of 12.24 centimetres) through the item to be heated. Microwave radiation is between common radio and infrared frequencies. Water, fat, and other substances in the food absorb energy from the microwaves in a process called dielectric heating. Many molecules like those of water are electric dipoles, they have a positive charge at one end and a negative at the other, this creates a circular motion as they rotate in order to try and align themselves with the alternating electric current field of the microwaves, as a result of this molecular movement, molecules collide creating heat. Some people sometimes argue that, microwave ovens cook food from the “inside out”. In reality, microwaves are absorbed in the outer layers of food in a manner somewhat similar to heat from other methods. The skeptics argue that the microwaves penetrate dry non-conductive substances at the surfaces of many common foods, and thus often induce initial heat more deeply than other methods. Depending on water content, the depth of initial heat deposition may be several centimetres or more with microwave ovens, in contrast to broiling (infrared) or convection heating, which deposit heat thinly at the food surface. Penetration depth of microwaves is dependent on food composition and the frequency, with lower microwave frequencies (longer wavelengths) penetrating better. eddie@afrowebs.com