Working of Microwave Oven |
Principle: |
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Microwaves have a frequency that can penetrate water, fat, sugar molecules, etc. and excite them.
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For a molecule to be excited, the electrons "revolving" the nucleus in the fixed orbits have to jump to higher energy levels.
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When this occurs, the atom starts to vibrate faster than normal.
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For example: |
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When this happens in a glass of water, all the atoms start moving haphazardly and collide with each other, thus creating friction.
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When friction is created, energy is given off in the form of heat.
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Working of microwave oven: |
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There is a device inside the oven that is the source of the microwave radiation called magnetron.
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The waves then travel to the oven cavity through the wave guide and stirrer.
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The waves penetrate the food and excite the molecules.
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This is why the food gets heated from the inside out. Because the waves are creating heat at the atomic level of the food which in turn cooks the item inside out.
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What are Hot spots? |
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Hot spots form because a microwave is sinusoidal, so it has peaks and valleys. Because of this, the micro waves cannot excite all of the atoms at once.
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The results are hot and cold spots in the microwave.
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The picture shows how micro-waves look in a microwave after they have reflected off the oven walls for a period of time.
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The peaks and valleys represent the hot spots and the flat areas represent the cold spots.
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This occurs because the peaks and valleys have a stronger intensity and it excites the atoms more quickly than the flat spots.
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