Microwaves

Microwave graphic


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Wavelength 1 x 10 ** - 4 m to 1 x 10 ** 2 m


 Discovered by:

James Clerk Maxwell in 1864.

Microwaves were first used for radar in WWII. (1939-1945) The development of microwaves is only one step of the gradual evolution of the concept and application of electromagnetic waves. Maxwell formulated a set of equations supporting all electromagnetic phenomena, which became known as Maxwell's equations. Hertz's experiment proved further generalizations and applications which led to the development of the microwave.


 Making Microwaves:

In a microwave oven, a magnetron generates and shoots out a beam of microwaves. The beam strikes the metal blades of a stirrer fan, which reflects and scatters the microwaves throughout the oven. The microwaves bounce off the metal waves and travel through plastic, glass, or paper to heat up water molecules in the food.


Microwaves are used in:

 Medicine:

In some cases microwaves relieve symptoms better than drugs. The use of microwaves is safer than surgery. For example, the wave can heat enlarged prostates, therefore killing extra tissue.

 Industry:

Microwaves can decrease air pollutants, disinfect hospital waste, improve dry cleaning solvents, and clean up contaminated soil.

 Science:

Satellite communications have used microwaves in the past. Scientists use microwaves to make chalcopyrite, a semi-conductor, made of copper. Microwaves can also be used to remove materials, and chemicals that can be used for analysis.

 Consumer goods:

Microwave ovens are used to heat and re-heat food evenly by agitating water molecules in food. Some burglar alarms send continuous microwaves (short radio waves) into an area. Any movement in that area disturbs the wave pattern and sets off the alarm.

 

 Communication:

Microwaves are used in cellular phones, telephones, telegraphs, television, and satellites.

 Dangers :  

Microwaves leaking from an oven may pose a hazard to people nearby. They are dangerous for women who are pregnant, because of the unknown defects caused by radiation leakage.

Precautions:

Metal containers should be avoided because they reflect microwaves, and prevent the microwaves from entering the food. Securing door seals and proper door closure helps to prevent microwave leakage. Microwave ovens that don't close securely should never be used.



Celestial bodies that Emit Microwaves:

Microwaves are not known to be produced by any celestial bodies.

Interesting Information not Included Above:

Microwaves move at the speed of light, which is 186,000 miles per second (300,000 kilometers per second) through empty space.

Microwaves are a type of electromagnetic energy like light waves. The one difference is that microwaves cannot be seen by the human eye. Microwaves have longer wavelengths than light waves. Like light waves, microwaves may be reflected and concentrated. Microwaves pass easily through rain, smoke, and fog which block lightwaves. Microwaves can pass through the ionosphere (which surrounds the earth and blocks or reflects longer radio waves).Microwaves are used in aircraft. High altitude power microwaves can be developed and used for communication and laser beam direction.

In the future, microwaves will be able to be used in landing systems for airplanes, and for the use of global navigation satellites.

Recent magazine article on microwaves:

Scientists are searching for better ways to break down hazardous wastes. Improved microwave heating methods can break down air pollutants and clean up contaminated soil. By removing water from radioactive sludge, it means less handling of hazardous waste and saves time and energy. Old electric circuits have become a mounting source of hazardous waste. With microwaves, researchers can recover precious metals and melt remainders. Microwaves can cook contaminated earth that is soaked with dangerous pentachlorophenols, destroying 99.9 percent of the noxious chemicals.

"Microwave heating" April 16, 1994

Contributors:

Moira Donahue
Stephanie Ohanessian
Patrick Wheeler
Christen March
Scott Burke
Tania Quispe
Stephanie Puglisi
Christianne Leonardopoulos
Robin Liu
Christina Christou

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