microwave oven

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Physics

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Presentation Transcript

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Microwave Oven

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You use microwaves everyday to heat different meals .The only thing you care about is hearing the beep sound signaling that you’ll soon be able to feed your grumbling stomach… But have you ever wondered how your food is cooked??? Lucky for you, we’re here to explain it all to you…

History : 

History Invented accidentally by Dr. Percy LeBaron Spencer While testing a magnetron during work, he discovered the candy bar in his pocket melted Experimented with other food products (popcorn and eggs), and realized microwaves can cook foods quickly In 1947, 1st commercial microwave oven produced (called Radarange) Mostly used by restaurants, railroad cars, ocean liners and military Improvement and refinements made ~ by 1967, 1st domestic microwave oven produced

Electromagnetic Spectrum : 

Electromagnetic Spectrum Electromagnetic radiation exists in a range of frequencies called the electromagnetic spectrum. Each frequency has a specific wavelength and as the frequency decreases, the actual length of the wave gets longer. Microwaves are obtained by the conversion of an electric energy into electromagnetic energy. Table 1: Frequency and Wavelength Range of Each Radiation Type in the Electromagnetic Spectrum.

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Its structure The magnetron The cooking chamber The glass door The rotating plate The transformer The guide The distributor The grid The walls

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The Function of the microwave oven as a whole

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Sensing that all systems are set to go, the signal activates triac, producing a voltage path to the high-voltage transformer. The high-voltage transformer along with a special diode and capacitor arrangement increases the typical household voltage from ~115 volts to ~3000 volts

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Inside the magnetron … The magnetron is the heart of the microwave. It is composed of vacuum tubes with empty compartments, with magnet on either end. This magnet creates a magnetic field.

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Inside the magnetron, a copper (Cu) wire receives the stooped up electric current. The electricity flows out from the Cu wire in beams of electrons. Those beams hit the electric wall (magnet) which sends them back, forming a U-shaped flow all along the edges. This phenomenon happens fast (really fast!). When electricity travels back and forth that fast, it makes microwaves.

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An antenna located inside the magnetron, sends out the microwaves into the waves guide, which channels the microwaves into the cooking chamber.

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The chamber walls are made of metal, which reflects microwaves like a mirror so they bounce right off.

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Thanks to the rotating tray in the cooking chamber, the microwaves can reach the food from all sides.

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The goal is to set all the molecules in motion (intermolecular friction exciting the food molecules) leading to the production of heat. That’s how we cook with microwaves.

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N.B: Non – polar substances such as glass and hard paper don’t get penetrated by microwaves; hence, there is no heating. This implies that they are used as food containers to heat food that is penetrated by microwaves.

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MAGNETRON TRANSFORMER & CAPACITER 4000V Waves of electromagnetic cooking energy (Microwaves) Cook food. ~115V

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10 Reasons to Throw Your Microwave Oven!!!

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From the conclusions of the Swiss, Russian and German scientific clinical studies, we can no longer ignore the microwave oven sitting in our kitchens. Based on this research, we conclude the following:

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1) Continually eating food processed from a microwave oven causes long term - permanent - brain damage by "shorting out" electrical impulses in the brain. [de-polarizing or de-magnetizing the brain tissue].

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2) The human body cannot metabolize [break down] the unknown by-products created in micro waved food. 3) Male and female hormone production is shut down and/or altered by continually eating microwaved food.

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4)The effects of microwaved food by-products are residual [long term, permanent] within the human body.

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5) Minerals, vitamins, and nutrients of all microwaved food is reduced or altered so that the human body gets little or no benefit, or the human body absorbs altered compounds that cannot be broken down. 6) The minerals in vegetables are altered into cancerous free radicals when cooked in microwave ovens. 7) The prolonged eating of microwaved foods causes cancerous cells to increase in human blood.

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8) Microwaved foods cause stomach and intestinal cancerous growths [tumors]. This may explain the rapidly increased rate of colon cancer in America.

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9) Continual ingestion of microwaved food causes immune system deficiencies through lymph gland and blood serum alterations.

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10) Eating microwaved food causes loss of memory, concentration, emotional instability, and a decrease of intelligence.

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HAVE YOU TOSSED YOUR MICROWAVE YET?!