Are sound waves always present in the air even though we might not be able to hear them? For example, if nothing is making noise in a room that we can hear, are there still inaudible sound waves in the room nonetheless? Also, what is the electromagnetic spectrum? I've been trying to find this out on my own, but I haven't found anything that has answered my question.
2006-10-20 03:52:11 · 10 answers · asked by Anonymous in Science & Mathematics ➔ Other - Science
by definition sound waves must be heard.
but if you're talking about molecular vibrations / frequencies, then yes, -something is always 'moving'. Molecules are bumping into each other.
2006-10-20 03:59:35 · answer #1 · answered by MK6 7 · 0⤊ 0⤋
Sound waves are the agitation of a media that, when they hit an ear, cause the brain to perceive a sound. So as long as you phrase it the way you did, the sound waves ARE always present. Whether they are a sound or not is the old philosophical question about the tree falling in the forest. A sound would require an ear to hear them, but a sound wave is just a sound wave.
As far as the electromagnetic spectrum, this is a completely different form of energy. Electromagnetic energy is derived from the movement of energetic particles and is not tied to any medium (as are sound waves). At one end of the electromagnetic spectrum is infrared, which we cannot see, but perceive as heat. This goes through all the colors of the rainbow to ultraviolet, radio waves, x-rays and gamma rays. The only difference between any of these is the amount of energy they contain. Infrared radiation is the least energetic, gamma radiation is the most energetic.
2006-10-20 04:18:23 · answer #2 · answered by Wally M 4 · 0⤊ 0⤋
Sound waves are vibrations in the air, or compressions and rarefactions. There is always some in the air. I disagree with the definition that they have to be heard because you need to consider who or what is listening. I can no longer hear things I used to be able to. Dogs can hear frequencies above human hearing. Elephants use infra-sound, frequencies below human hearing. So I would define sound as the compression/rarefaction waves in the air, regardless if they are audible to humans or not.
As far as the electromagnetic spectrum, follow the link below for more information. It should help.
2006-10-20 17:23:52 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Yes, sound waves are present. Something is always making sound, whether it's you taking a step or whatever. There are different types of sound, as well--some types are inaudible to you (but other organisms can hear them), so there's prolly some sound that you can't hear that's hanging out in your room with you.
Here's some helpful info:
http://www.glenbrook.k12.il.us/gbssci/phys/Class/sound/u11l1a.html
http://www.glenbrook.k12.il.us/gbssci/phys/Class/sound/u11l2d.html
As for the electromagnetic spectrum, it has to do with light. Just like sound, there are different kinds of light, and not all are visible to the human eye. In fact, there is a very short range that IS visible to humans (called 'visible light.') Go here:
http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html
2006-10-20 04:02:38 · answer #4 · answered by TheAutumnPhoenix 3 · 0⤊ 0⤋
Sound is the compression of air, noise is the human perception of that. It's like the tree falling in the forest. It makes a sound, but not a noise.
Electromagnetic spectrum - in a word, light!
Visible light is part of the EM spectrum, which also includes infra-red (just beyond red), ultra-violet (just beyond violet), microwaves, x-rays, radio waves and gamma rays.
Created by the oscillations of electric and magnetic fields.
2006-10-20 04:16:57 · answer #5 · answered by Morgy 4 · 0⤊ 0⤋
Sound as we know it is not a good test,a dog can hear many sounds we can not.
The electromagnetic spectrum is all radio communications what u want to know about that.
2006-10-20 04:12:30 · answer #6 · answered by JOHNNIE B 7 · 0⤊ 0⤋
Sound waves are attenuated in the time so that means their amplitude decreases when they propagate. So at certain point they disappear.
That's true that by reflexion or other reason you can create harmonic (sound wave = frequency and harmonic is a sound wave with its frequency multiplied by a factor)
this harmonic are inaudible... but their amplitude decreases as well during the propagation and they disappear too.
2006-10-20 04:07:44 · answer #7 · answered by Anonymous · 0⤊ 0⤋
Sound is just lots of vibrations that are converted by e.g. ouur ear or a speaker.
They almost always there. Even the clicking of a keyboard produces sound waves, otherwise how would we hear it?
2006-10-20 05:20:04 · answer #8 · answered by Kat W 2 · 0⤊ 0⤋
It is weird but one hears that Sound Waves keep travelling out
and you could pick up a radio broadcast in outer space from the
40's or 50's but that doen't make sense unless saound waves
can defy gravity. I think they just disapper, vanish or return to
Earth and are scattered.
2006-10-20 04:02:37 · answer #9 · answered by Anonymous · 0⤊ 0⤋
radio is always on...think about that. Sirus radio 24/7 sound waves that need a receiver
2006-10-20 04:06:36 · answer #10 · answered by Jip Jip 7 · 0⤊ 0⤋