Microwaves

What are they?
A microwave is a high-frequency radio wave. It is often used to cook food in a microwave oven. They are the second shortest waves on the em spectrum.
Microwave overns are not dangerous
Microwave overns are not dangerous

We cannot see them. They can quickly penetrate quite deep into materials that contain water, for example most food(in microwave ovens). The energy in these waves makes the water molecules vibrate faster, which means the water gets hotter.

Are they dangerous?
There is evidence to show that microwaves are dangerous, but not from microwave ovens. Prolonged exposure to microwaves is known to cause "cataracts" in your eyes, which is a clouding of the lens, preventing you from seeing clearly.

How do we detect them?
Radar is an acronym for "radio detection and ranging". Radar was developed to detect objects and determine their range (or position) by transmitting short bursts of microwaves. The strength and origin of "echoes" received from objects that were hit by the microwaves is then recorded.

an eletromagnetic wave
an eletromagnetic wave

the electromagnetic spectrum
the electromagnetic spectrum



Where do they come from?
Microwaves are basically extremely high frequency radio waves, and are made by various types of transmitter.
In a mobile phone, they're made by a transmitter chip and an antenna, in a microwave oven they're made by a "magnetron". Their wavelength is usually a couple of centimetres. Stars also give off microwaves.
a magnetron
a magnetron


What can they be used for?
Microwaves are good for transmitting information from one place to another because microwave energy can penetrate haze, light rain and snow, clouds, and smoke.They are used to heat food up in microwave ovens, in phone arials and in the use of some sattilites.Microwaves are also used by fixed traffic speed cameras, and for radar, which is used by aircraft, ships and weather forcasters.
the inside of a microwave oven
the inside of a microwave oven


Anything else interesting?
They are normally a couple of centimeters long. The only longer wave is a radiowave and the next shortest is a infraredwave. It's the second longest wave.

The Comic Microwave Background
The Cosmic Microwave Background radiation, or CMB for short, is a faint glow of light that fills the universe.It's the residual heat energy from the big bang 14 billion years ago. It's the oldest light in the universe but it's also got the strongest glow in the microwave region of the radio spectrum.
The Cosmic Microwave Background
The Cosmic Microwave Background



all images and captions from google.



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!).



Gamma
X-rays
UV
visible
IR
microwaves
radio
How are they
generated?
They are classically produced
by gamma decay and can also
be created in nuclear explosins
X-rays are generated by an X-ray tube,a
vacuum tubethat uses a high voltage
to accelerate the electrons released by a
hot cathode to a high speed
They can come from the sun,
but you can get man made
lamps for experimental perposes.
Light waves are given off
by anything that's hot
enough to glow.
This is how light bulbs
work.
IR waves mainly
come from the
sun and fire.
They are made by
various types of
transmitter
Radio waves are
energy waves that
are generated by a transmitter.
How are they
detected?
You could use a gieger
meter which detects radiation
X-rays can be detected with a special
peice of equiptment called an x-ray
detector
You could use a UV
dectector
They are detected in our
eye.
Night-vision goggles
or infrared cameras
allow us to "see" the
infrared waves
emitting from warm
objects such as
humans and animals.
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.
Antennas designed to
detect radio waves are
usually similar in size
to the wavelength they
want to detect
How might they be
dangerous?
They cause biological harm astheir rays are ironing radiation
X- rays can damage cells and cause cellmutation which can cause cancer or cell
death
It can be dangerous as they
damage and kill cells. When
this happens to us we call
it sun burn.
Too much light can damage
the retina in your eye.
This can happen when you
look at something very bright,
such as the Sun.
Infrared waves are
heat waves. If the
cells absorb too
much infrared
radiation the
heating will
damage or kill
the cells.
Prolonged exposure to
microwaves is known to
cause "cataracts" in
your eyes, which is a
clouding of the lens,
preventing you from
seeing clearly.
Radio waves are not
dangerous because
they have a low
frequency.
What are the main
or most significant
uses?
They can be used in medicine
to treat cancer.
X- rays can be used to look at the internal
structure of objects, they are often used in
airport scanners.They are also used in
hospitals to look at ,posible,
broken bones.
Ultraviolet waves have many
uses, including security markings,
fluorescent lamps, detecting forged
bank notes, disinfecting water and
killing off germs. .
We use light to see things.
A remote control
uses light waves
just beyond the
visible spectrum
of lightto change
channels on your TV.
Infrared is also used
for cooking in grills
and toasters.
Microwaves are good
for transmitting
information from one
place to another and
they are used to heat
food up in microwave
ovens
They can be used
for transmitting sound
and television signals,
radio is used for the
transmission of data
in coded form.

Good work. You have selected good material for the microwaves section and the well chosen imges work well.
The table has some formatting issues but the content is good.

A-
<Home page>