Radio waves


What are they?
Radio waves make up part of the electromagnetic spectrum. These waves are packets of energy with differing wavelengths, similar to visible light waves, X-rays or Gamma rays, except longer.
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Are they dangerous?
radio waves are not dangerous because they have a low frequency. Large doses of radio waves are believed to cause cancer, leukaemia and other disorders. Some people claim that the very low frequency field from overhead power cables near their homes has affected their health.
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Where do they come from?
Radio waves are energy waves that are generated by a transmitter. Radio waves are also known as electromagnetic radiation and the typical shape of the wave produced by a transmitter is that of a sine wave.
external image antenna_and_radio_waves.png
How do we detect them?
Antennas designed to detect radio waves are usually similar in size to the wavelength they want to detect. This is why many radio antennas have to be very long. If the antennas are not close to the size of the wavelength they do not usually do a good job of detecting the waves.
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What can they be used for?
They can be used for transmitting sound and television signals, radio is used for the transmission of data in coded form. In the form of radar it is used also for sending out signals and picking up their reflections from objects in their path. Long-range radio signals let astronauts to communicate with the earth from the moon and carry information from space as they travel to distant planets. For navigation of ships and aircraft the radio range, radio compass , and radio time signals are used. Radio signals sent from global satellites can also be used by special receivers to tell us where we are. Digital radio and satelite provides helps the audio and volume.

Read more: radio: Uses of Radio Waves | Infoplease.com http://www.infoplease.com/encyclopedia/science/radio-uses-radio-waves.html#ixzz2qfWQZu00
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Anything else interesting?
They are given off by stars, sparks and lightning, which is why you hear interference on your radio in a thunderstorm.
For low frequency radio waves diffraction can allow them to be received behind hills, although repeater stations are often used to improve the quality of the signals.


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?
Gamma rays come
from stars,super
novas, black holes and
pulsars. They are
also created on earth
by natural radioactive
decay,by nuclear
explosion and by
lightning in thunderstorms.
X-Ray tube or
objects in space
They can come
from the sun,
but you can
get man made
lamps for
experimental
perposes.
hot thingslumenecnt things
stars
photons
lots of objects
produce infrared
energy, anything
living or warm
will produce
a certain amount.
They are
emitted from
large stars
and in mobiles
they are made
with a transmitter
chip and an
antenna
Transmitters
How are they detected?
captured and reflected
by mirrors
In hospitals the
pictures were
captured using
image receptors
such as thin films
and photographic
plates.
To detect
them you
can simply
use a filtrate.
our eyes can
detect them.
Night-vision goggles
and secial detectors
can allow us see
warm objects
emitting this type
of energy.
Receivers if
they are used
in mobile phones.
Antennas designed
to detect radio
waves are usually
similar in size to
the wavelength
they want to detect.
How might they be dangerous?
They're very dangerous
becausethey are
radioactive
X- rays can damage
cells and cause
cause cell mutation
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.
No
They are heat waves
so too much heat will
damage or kill cells
causing burns.
Prolonged
exposure can
damage the
cataracts.
Radio waves
are not dangerous
because they have
a low frequency.
What are the main or most significant uses?
Gamma rays can abe
used to go through the
skin to kill cells, such
as cancerous cells.
This can be used to
cure some types of
cancer.
To scan for bone
breakages or in
dentists.
Ultra violet
rays can be
used for
tanning, in
a tanning
bed or by
the sun.
Seeingdisplaying info
lighting areas
They can be TV
remotes used to
change channel
and cokking and
grills
Microwaves
cause water
and fat molecules
to vibrate, which
makes the
substances hot.
Communications

Very good work. You have made good use of images (remember to explain or caption them). The content is just right.
The table has been done well.

Well done!
A-

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