----- Original Message -----
Sent: Sunday, October 28, 2001 1:25
PM
Subject: Re: [Electronics_101] Fw:
communication concepts ??
Here is a high-level explantion:
?
Sound is nothing more than compressions and
decompressions of air.? Look at a speaker and?think of the way if
pulsates back and forth.? This is producing these compressions and
decompressions.? Since there is nothing to compress in a vacuum, sound
cannot travel through it.
?
Although I could visualise how sound waves
propagate, just like dropping a 10cent coin into a pool of water, it is a
serious mistake to use the above "speaker example" to illustrate how sound
waves travelled because the above eg. has nothing to do with sound waves, it
simply decode the the signal from the microphone (input), then subsequently
encode it back to the speaker. This has nothing to do with sound except
electro-magnetic waves.
?
Electromagnetic waves are different.? These
are not compressions and decompressions (of air at least).? In fact,
no-one truly knows who the electromagnetic waves really work.? They can
travel through a vacuum at the speed of light (3 * 10^ 8 m/s).?
?
I personally think that electro-magnetism
is a force, therefore electromagnetic waves = electromagnetic force. and force
can travel thru vacumn, thats how our rockets flies to the moon.
?
