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How does the microwave work?
Microwaves are a form of high frequency radio waves similar to those
used by a radio including AM, FM, and CB. They are, however, much
shorter than radio waves; approximately 12 cm long. Electricity is
converted into microwave energy by the magnetron tube. From the
magnetron tube, microwave energy is transmitted and absorbed.
Reflection
Microwaves are reflected by metal just as a ball is bounced off a wall.
A combination of the interior walls and the rotation of the food on the
turntable ensure that the microwaves are well distributed within the
oven cavity to produce even heating of foods.
Transmission
Microwaves pass through some materials such as paper, glass and
plastic much like sunlight shining through a window. Because these
substances do not absorb or reflect the microwave energy, they are
ideal materials for microwave oven cooking containers.
Absorption
During heating, microwaves will be absorbed by food. They penetrate
to a depth of about 1-5 cm. Microwave energy excites the molecules in
the food (especially water, fat and sugar molecules), and causes them
to vibrate at a rate of 2,450,000,000 times per second. This vibration
causes friction, and heat is produced just as you will feel heat produced
if you vigorously rub your hands together. The internal heating of larger
foods is done by conduction. The heat which is produced by friction
travels by conduction to the centre of the food. Foods also continue to
heat by conduction during standing time.
Because microwaves dissipate, much like sunlight as it reaches the
Earths surface, they are not stored in food.
Radio Interference
1. Operation of the microwave oven may cause interference to your
radio, TV or similar equipment.
2. When there is interference, it may be reduced or eliminated by
taking the following measures:
a. Clean the door and sealed surfaces of the oven. (See Care of
Your Microwave Oven found on page 7.)
b. Place the radio, TV, etc. as far away as possible, from the
microwave.
c. Use properly installed antenna, to obtain stronger signal
reception.
