MICROWAVE RADIATION

Intro: MICROWAVE RADIATION

I love microwaves, I think they are the coolest thing ever. My science teacher even let me teach a lesson (that I made) on microwaves! On this instructable I will teach you a thing or two about microwave radiation.

STEP 1: History of Micorwaves

Microwaves were first predicted by James Clerk Maxwell (second picture) in 1864 by use of his equations. Later during 1888 Heinrich Hertz  (third picture) proved the existence of microwaves by building a device that produced and detected microwave radiation. His device used a horse trough, a wrought iron point spark, Leyden jars, and a length of zinc gutter with a parabolic cross-section that worked as a reflection antenna. In 1894 J. C. Bose  (fourth picture) publicly demonstrated radio control of a bell using millimeter wavelengths, and conducted research into the broadcasting of microwaves.

STEP 2: Microwaves

Microwaves are a form of electromagnetic waves just below infrared light, with a wavelength ranging from one meter to one millimeter. Microwave frequencies can be as low as 300MhZ and as high as 300GhZ. Microwaves are non-ionizing radiation so according to many beliefs microwaves cannot cause cancer, but can aid in it if exposed for to long. (this guy believes microwaves can cause cancer but is always changing his mind...)  

STEP 3: Microwave Chemistry

Microwaves react with mobile polarized materials such as water, sugars, and fats. When microwaves pass through a material containing a polarized liquid such as water, the waves alter the polarity causing them to vibrate extremely fast causing friction which heats up the material, this is known as dielectric heating. When placing a light bulb or neon lamp in a microwave you will notice a plasma flame within, this is because the metal parts are acting as an antenna and the microwaves are converted back into electrons which ionize the gases.

STEP 4: Producing Microwaves

Microwaves are produced by vacuum tubes devices that operate on the ballistic motion of electron controlled by magnetic or electric fields. Some different kinds of microwave emitters are the cavity magnetron, the klystron, the traveling-wave tube(TWT), the gyrotron and all stars. These devices work in the density modulated mode, instead of current modulated mode, meaning that they work on the basis of clumps of electrons flying ballistically  through them, instead of using a constant flow of electrons. Lower power microwaves can me produced by some solid state devices such as the FET (field effect transistor), the tunnel diode, the gunn diode, and the IMPATT diode.

The fist picture is a gunn diode with a waveguide, the second are some different kinds of cavity magnetron's, the third is a gyrotron, the fourth and fifth are klystron tubes, and the last is a traveling wave tube.

STEP 5: Microwave Communication

Before fiber optics and such things were invented microwaves were used to carry most long distance calls but now we have fiber optics and such things but still use microwaves as a means of communication. Wireless LAN protocols, such as Bluetooth, use microwaves in the 2.4 GhZ range. Microwaves are also used in broadcasting and telecommunication transmissions because of their short wavelength, highly directional antennas are smaller and therefore more practical than they would be at longer wavelengths. There is also more bandwidth in the microwave spectrum than in the rest of the radio spectrum; the usable bandwidth below 300MhZ is less than 300MhZ while many GhZ can be used above 300 MhZ. Usually microwaves are used in television news to transmit a signal from a remote location to a television station from a van equipped with a microwave transmitter. 

STEP 6: Making Your Own Microwaves

Want to experiment with microwaves? All you need is a microwave oven to take apart and a bit of metal and follow this instructable and you got yourself some microwave radiation to experiment with (it would be safer if you just left the microwave in tact and used the cooking chamber).

STEP 7: Microwaves and You

As much as you may love microwaves they don't love you so you gotta be careful around them!  Microwaves do not have enough energy to chemically change substances by ionization because they are below the level of non-ionizing radiation. The word "radiation"only means that energy can radiate. It dose not mean radioactive in this case but it can. It has not been shown conclusively that microwaves have enough adverse biological effects at low levels. Some but not all studies suggest that long-term exposure may have a carcinogenic effect. This is separate from the risks associated with very high intensity exposure, which can cause heating and burns like any heat source, and not a unique property of microwaves specifically.During World War II, it was observed that individuals in the radiation path of radar installations experienced clicks and buzzing sounds in response to microwave radiation. This microwave auditory effect was thought to be caused by the microwaves inducing an electric current in the hearing centers of the brain. Research by NASA in the 1970s has shown this to be caused by thermal expansion in parts of the inner ear. When injury from exposure to microwaves occurs, it usually results from dielectric heating induced in the body. Exposure to microwave radiation can produce cataracts by this mechanism, because the microwave heating denatures proteins in the crystalline lens of the eye faster than the lens can be cooled by surrounding structures. The lens and cornea of the eye are especially vulnerable because they contain no blood vessels that can carry away heat. Exposure to heavy doses of microwave radiation (as from an oven that has been tampered with to allow operation even with the door open) can produce heat damage in other tissues as well, up to and including serious burns which may not be immediately evident because of the tendency for microwaves to heat deeper tissues with higher moisture content. NEVER get inside a microwave and close the door, you can't always get out!

Comments

[sbrozt]

Hi, reading your article, I can only say you're wrong. First, excuse my bad English. I work with transmitters much smaller than a microwave power and suffer tinnitus. With the microwave time is not important, but the dose you receive is important. Think that nothing will happen if the molecules of your body change position 2,500,000,000 per second?. A watt and half non-ionizing radiation kills your sperm in 12hrs. Also liquefies your blood and causes damage to the DNA. Never expose yourself to a magnetron !!! Stay away from WIFI and Bluetooth. Use wired, not wireless phones. Use the cell phone for short periods of time, and stay away from the antenna masts. You must inform more, you can produce you one irrebersible damage in a very short time. Greetings. Visit http://www.bioinitiative.org/

[samx.goose]

Hi, I went and looked at the report you linked. and it looks like mostly conspiracy theories, the 'evidence' they had I found to be inconclusive. the way that the studies were done I.E. self administered questionnaires, among others, which are not the most reliable sources of information. not including the millions of people just in the U.S. who use smartphones everyday and don't develop cancer.

[iceng]

Military honchos in the cold war told me they used to step in front of power transmitters just enough to raise sperm temp making them impotent for a weekend of pleasure on leave...

[jelansayed177]

pls the referance

[samx.goose]

so now all you have to do is stick a spider in a microwave and then let it bite you.

[KirstenD8]

Informative article, I have heard that microwaves produce small amounts of radiation but still not sure if it harms human’s health on daily basis while using microwave ovens. I am thinking of purchasing a Geiger counter for my household at ecotestgroup.com to detect radiation at home. I also found some interesting information on microwaves usage, for example: microwaves are used to detect speeding cars and to send telephone and television communications. Industry uses microwaves to dry and cure plywood, to cure rubber and resins.

[dbiswas6]

Hey! How the hell do i make/get a waveguide ????

[iceng]

You take a senior math course on how to calculate curls of electric/magnetic field vectors and then wave guide theory...

[fixitnotbroken]

fascinating well done,.. informative... short and to the point. do i sound like your English teacher? you gave me enough knowledge to understand what we all now take for granted. I have some friends that wont enter a room witha microwave in it and others who use them for all the kitchen needs. I am still learning about them,..I thank you very much. The grape exp. played but the other utube didnt.

[jbaker22]

Are there any materials that do not reflect microwaves and are electrically conductive?

[craftydan]

Cute Article,  Not much instructions as much as education, but still a cute science report.

You did miss one critical point:

What EM radiation in the microwave region does to people.

With that in mind, unless you want to risk STERILITY and BLINDNESS, best to give that last step a pass.