Microwaves :: essays research papers

You might remember the heroic division that youngly-invented radar played in the Second WorldWar. People hailed it and so as "Our Miracle Ally".But even in its earliest years, as it was helping winthe war, radar proved to be more than an dexterousenemy locator. Radar technicians, doodling awayin their idle moments, found that they could think aradar beam on a marshmallow and toast it. Theyto a fault popped popcorn with it. Such was thebeginning of zap readying. The very analogous vigor that warned the British of the Ger humankindLuftwaffe invasion and that policemen employ topinch speeding motorists, is what some of us nowhave in our kitchens. Its the same as what carries colossal distance phone calls and cablevision. Hitlersarmy had its own version of radar, using radio setwaves. But the trouble with radio waves is thattheir long wavelength requires a large,cumbersome advance to focus them into a narrowradar beam. The British showed that microwaves,with their shor t wavelength, could be focussed inanarrow beam with an antenna many times smaller.This enabled them to desexualise more effective use ofradar since an antenna could be carried on expressioncraft, ships and mobile ground stations. Thischaracteristic of microwaves, the efficiency withwhich they ar concentrated in a narrow beam, isone reason why they can be used in cooking. Youcan produce a high-powered microwave beam ina small oven, but you cant do the same with radiowaves, which are simply too long. Microwavesand their Use The idea of cooking with radiationmay seem like a fairly new one, but in fact itreaches back thousands of years. Ever sincemastering fire, man has cooked with infraredradiation, a close kin of the microwave. Infraredrays are what leave you that warm glow when youput your hand near a mode radiator or a hotplateor a campfire. Infrared rays, move from the sunand striking the atmosphere, make the Earth warmand habitable. In a conventional gas or electricoven, infr ared waves pour finish off the hot elements orburners and are converted to heat when theystrike air inside and the food. Microwaves andinfrared rays are related in that both are forms ofelectromagnetic ability. Both consist of electricand magnetic fields that mount up and fall like waves onan ocean. Silently, invisibly and at the speed oflight, they croak through space and matter. Thereare many forms of electromagnetic energy (seediagram). Ordinary light from the sun is one, andthe only one you can in truth see. X-rays areanother. Each kind, moving at a separatewavelength, has a unique effect on any matter it