Microwaves :: essays research papers

You might remember the heroic role thatnewly-invented microwave radar played in the Second WorldWar. People hailed it then as "Our Miracle Ally". scarce even in its earliest years, as it was dowery winthe war, radar proved to be more than than an expert competitor locator. Radar technicians, doodling awayin their idle moments, found that they could centre aradar commit on a marshmallow and toast it. Theyalso popped popcorn with it. Such was thebeginning of microwave cooking. The very sameenergy that warned the British of the GermanLuftwaffe invasion and that policemen employ topinch speeding motorists, is what many of us nowhave in our kitchens. Its the same as what carrieslong outdistance phone calls and cablevision. Hitlersarmy had its own version of radar, using radio receiverwaves. But the trouble with radio waves is thattheir long wavelength requires a large,cumbersome antenna to focus them into a narrowradar beam. The British showed that microwaves,with their sho rt wavelength, could be foc utilize inanarrow beam with an antenna many times smaller.This enabled them to make more effective use ofradar since an antenna could be carried onaircraft, ships and ready ground stations. Thischaracteristic of microwaves, the efficiency withwhich they argon concentrated in a narrow beam, isone reason why they can be used in cooking. Youcan produce a high-powered microwave beam ina small oven, further 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 give you that quick glow when youput your hand near a room radiator or a livelyplateor a campfire. Infrared rays, flowing from the temperatenessand striking the atmosphere, make the Earth warmand habitable. In a formulaic gas or electr icoven, infrared waves pour off the hot elements orburners and are converted to heat when theystrike air internal and the food. Microwaves andinfrared rays are related in that both are forms ofelectromagnetic energy. Both consist of electricand magnetic fields that rise and root like waves onan ocean. Silently, invisibly and at the speed oflight, they travel by space and matter. Thereare many forms of electromagnetic energy (seediagram). so-so(predicate) light from the sun is one, andthe only one you can actually see. X-rays areanother. Each kind, moving at a separatewavelength, has a fantastic effect on any matter it