Microwaves :: essays research papers

You might remember the heroic role thatnewly-invented radar played in the encourage WorldWar. People hailed it then as "Our Miracle Ally". unless even in its earliest years, as it was helping winthe war, radar proved to be more than an expertenemy locator. Radar technicians, doodling awayin their idle moments, found that they could focus aradar beam on a marshmallow and assurance 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 some(prenominal) of us nowhave in our kitchens. Its the same as what carrieslong distance phone calls and cablevision. Hitlersarmy had its own version of radar, using radiowaves. But the trouble with radio waves is thattheir long wavelength requires a large,cumbersome antenna to focus them into a determineradar beam. The British showed that microwaves,with their short wavelength, could be focussed 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 mobile ground stations. This symptomatic of microwaves, the efficiency withwhich they are concentrated in a narrow beam, isone reason why they can be used in cooking. Youcan pose a high-powered microwave beam ina small oven, but you cant do the same with radiowaves, which are simply too long. Microwavesand their utilisation The idea of cooking with radiationmay seem like a fairly new one, but in fact itreaches back thousands of years. Ever since get the hang fire, man has cooked with invisibleradiation, a close kin of the microwave. Infraredrays are what give you that warm glow when youput your hand near a agency radiator or a hotplateor a campfire. Infrared rays, flowing from the sunand striking the atmosphere, make the Earth warmand habitable. In a stuffy gas or electricoven, infrared waves pour off th e 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 energy. Both consist of electricand magnetic fields that rise and fall like waves onan ocean. Silently, invisibly and at the speed oflight, they travel through space and issue. Thereare many forms of electromagnetic energy (seediagram). Ordinary light from the sun is one, andthe whole one you can actually see. X-rays areanother. Each kind, moving at a separatewavelength, has a unique effect on any matter it