Microwaves

One of the more common forms of the microwave.
One of the more common forms of the microwave.
The Cosmic Microwave Background
The Cosmic Microwave Background

What are they?

Microwaves are a high frequency radio wave that have a wavelength of about 12 centimetres long and have a number of applications. They are found everywhere from outer space to your kitchen and weather satellites. On the electro-magnetic spectrum they are located in-between infrared and radio waves.

Are they dangerous?

Prolonged exposure to microwaves is known to cause cataracts, which is a clouding of the lens, in your eyes preventing you from seeing clearly. Recent research indicates that microwaves from mobile phones can affect parts of your brain - after all, you're holding the transmitter right by your head. Although there is a feeling that you're more vulnerable if you're young and your brain is still growing.

Where do they come from?

Microwaves are emitted from a number of sources, for instance, in a mobile phone, they are generated by a transmitter chip and an antenna,
while in a microwave oven they are generated by a 'magnetron'. They are also released as a form of electromagnetic radiation from large stars
external image 205-004-F27EDE44.jpg
external image Dust_disk_around_massive_star.jpg

How do we detect them?


Because humans cannot detect electromagnetic radiation we need special tools to detect them. If the waves are used for communications we use a reciver to detect them. If we are checking for contamination we can use a gieger tube to test for them.

What can they be used for?

Microwaves cause water and fat molecules to vibrate, which makes the substances hot. Therefore we can use microwaves to cook many types of food. Mobile phones use microwaves, as they can be generated by a small antenna, which means that the phone doesn't need to be very big. The drawback is that, being small, they can't put out much power, and they also need a line of sight to the transmitter. Microwaves are also used by fixed traffic speed cameras, and for radar, which is used by aircraft, ships and weather forcasters. The most common type of radar works by sending out bursts of microwaves, detecting the "echoes" coming back from the objects they hit (like a bat uses echo location), and using the time it takes for the echoes to come back to work out how far away the object is. They are also used to transmit data over long distances with satelites.

Anything else interesting?


The microwave oven, born in 1946, grew into a multimillion-dollar industry. In fact, by 1994 these kitchen appliances could be found in 90 percent of American homes. The microwave oven was an accidental byproduct of World War II research into the use of vacuum tubes called magnetrons. These devices generated the microwave radiation required by radar equipment to detect enemy ships and aircraft.



Fibre Optic Cables


What are they?

Fibre optic cables are a type of wire that carry digital data at the speed of light. They can bend and are often put into bundles to maximise the capacity of the wire.
external image Fibre%20Optics,%20Wire%20and%20Cables%202_tcm35-8480.JPG

Are they dangerous?

Unless you hang/strange yourself with them then no.

Where do they come from?

Big factories that make them. Internet and phone providers lay them.

How do we detect them?


Ermmm..... We could use a X-ray on the ground or look for the helpful sign things.


In the table below, fill the cells with very brief notes. Use the other pages to gather the information from, and you may want to go outside of this wiki if you really can't find the information here (though I'd be surprised!).


Rays:
Gamma
X-rays
UV
visible
IR
microwaves
radio
How are they generated?
Pulsars
stars
super novai
black holes
nuclear explosions
X-ray tube
photons
pulsars
The sun
Special lamps
hot things
lumenecnt things
stars
photons
NOT THE MOON
Everything with a temp above absolute 0
Tranmiter
magnatron
transmiter
How are they detected?
Dense crystal blocks
energy from electrons
films
photographic plates
Filtrate
UV detector
our eyes
infrared camera

night vision goggles
Reciver
Reciver
How might they be dangerous?
Yes, cancer
Yes, cancer
Yes & no
C + B types will but A wont
No
Yes (Prolonged Exposure)
Damage/Kill
cells
Yes (over time), cataracts
brain damage
No
What are the main or most significant uses?
Killing cancerous
cells.
Internal Structures
Tanning
Killing microbes
Seeing
displaying info
lighting areas
Remote control
Some grills/ toasters
seeing in dark
Comunications
Heating food
Communications

Very good work. The content is just right and the images work well (remember to caption or explain each one),
The table is good - as it doesn't have too much information.
Well done!
A-

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