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MICROWAVE OVENS Physics 001, Section 001 John Hopkins By: Vasavi Pandey.

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Presentation on theme: "MICROWAVE OVENS Physics 001, Section 001 John Hopkins By: Vasavi Pandey."— Presentation transcript:

1 MICROWAVE OVENS Physics 001, Section 001 John Hopkins By: Vasavi Pandey

2 THE START OF THE MICROWAVE OVEN 1945; the high power microwave was discovered by accident by American engineer Percy Spencer  Spencer was working on an active radar when he discovered the chocolate in his pocket had melted because of microwaves  After that, the first food to deliberately be cooked by a microwave oven was popcorn; second was an egg  Spencer, at the time, worked for Raytheon, a major American "defense contractor"  The company filed for patency in October of 1945 for Spencer's microwave process and an oven that heated food using microwave energy Spencer confirmed all his findings by creating a high density electromagnetic field "by feeding microwave power from a magnetron into a metal box from which it had no way to escape"  When placing food into the metal box, its temperature rose quickly

3 HOW IT WORKS Microwaves use the behavior of water molecules when subjected to electromagnetic waves In simple terms, microwaves are electromagnetic waves with wavelengths in the range of 1mm - 1m  Microwaves used for cooking are electromagnetic waves processing frequencies around the 2.45 GHz range Electromagnetic waves are waves made up of altering electric and magnetic fields  When a positively charged electron is exposed to an electric field, it experiences a force pointing in the direction of the field  When a negatively charged electron is exposed to the same field, it experiences a forced pointing in the opposite direction of the field Since an electromagnetic wave (like a microwave) is made up of alternating electric fields, a charge exposed to it will experience forces in changing directions

4 HOW IT WORKS (CONT.) For water molecules, which are dipoles, the net effect would force the molecules into rotation  Since the fields are alternating, the rotation will change from clockwise to counter-clockwise at regular time intervals The water molecules then possess heat energy that rub off of nearby molecules --thus heating the entire body uniformly  Electromagnetic waves in the microwave range are most suitable for this because the water molecules readily rotate when exposed to such frequencies.  This goes on and heats up the food inside the microwave

5 VARIOUS USES FOR THE MICROWAVE OVEN 1.Dry up herbs 2.Roast garlic 3.Make popcorn 4.Soften sugar 5.Steralize garden soil 6.Dye fabric 7.Decrystalize Honey 8.Create a giant crayon

6 THE MICROWAVE AND PHYSICS 001 The microwave oven uses microwaves, a form of a wave  Researching the microwave oven goes further into learning about waves and understanding how they work  This relates also to what type of wave an electromagnetic wave is in relation to other waves WHAT I LEARNED It was really interesting to learn about the microwave oven because I never really understood how the device worked A microwave is an every day device that no one really puts much thought into; we just use it and take it for granted  It was nice to understand what goes into making a microwave oven I learned how electromagnetic waves and water molecules are both used together to get a microwave working. Before researching the device, I never would have put the two together. I also learned how the device heats up food items. I also got even a stronger understanding of waves

7 BIBLIOGRAPHY 1."Electromagnetic Waves." Drexel. Drexel, 12 May 2011. Web. 20 Apr. 2014.. 2.VILLANUEVA, JOHN C. "How Do Microwaves Work." Universe Today. N.p., 18 Nov. 2009. Web. 19 Apr. 2014..

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