How Does the Microwave Work?, Reflection

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 stationary (interior walls) and rotating antenna, located underneath the bottom shelf and above the ceiling cover assure that the microwaves are well distributed within the oven cavity to produce even heating or cooking 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 Earth’s 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 18.)

b.Place the radio, TV, etc. as far away as possible, from the microwave.

c.Use a properly installed antenna, to obtain stronger signal reception.

- 6 -