Science: Light
Visible sound   (+9, -2)  [vote for, against]
Gaseous additive which makes sound waves visible

This is actually a childhood dream, but the annotation to the Darth Maul Toothbrush reminded me of it. In my dream, any region of air which had loud noises passing through it would turn a lovely blue colour (RGB 0,153,255), so as you spoke, there'd be a vague blue cloud in front of your mouth; A particularly loud fart would result in a tell-tale blue cloud next to your bum; Aeroplanes passing overhead would be surrounded in a blue cloud, and so on.
Hard to see how to actually do this. Some weird gas which exhibits interference properties when vibrated with the right frequency sound maybe?
-- hippo, Aug 10 2000

Hey, Egnor, look at this!
Your annotation reminded me of this photo. Not quite what I meant, but very pretty. [hippo, Aug 10 2000, last modified Oct 21 2004]

Synaesthesia, the scientfic name for the phenomenon of actually experiencing this
This is probably what you're thinking of hippo. Should answer your question as well. [vincebowdren, Aug 10 2000, last modified Oct 21 2004]

Sonic Boom picture, with some explanation http://antwrp.gsfc..../apod/ap010221.html
[hippo, Aug 10 2000, last modified Oct 21 2004]

(?) The Prandtl-Glauert Singularity http://www.eng.vt.e.../conden/pg_sing.htm
It's worth noting that these condensation clouds are *not* "pictures of a sonic boom", nor is it necessary to take the photo just as the aircraft "breaks the sound barrier", despite what many photo captions (incorrectly) claim. This page explains the phenomenon in more depth and includes lots of pretty pictures. [egnor, Aug 10 2000, last modified Oct 21 2004]

More info about synaesthesia http://www.wardle.d.../books/cytowic.html
Good book (Not in the same league as Oliver Sachs though, IMHO) [Pallex, Aug 10 2000, last modified Oct 21 2004]

Sonic Boom Video http://www.eng.vt.e...ery/conden/f14.mpeg
Here's a video some lucky cameraman got of the condensation cloud around a supersonic aircraft [Qwerty0, Oct 04 2004, last modified Oct 21 2004]

Seeing Sound
A modern approach exploiting the Acousto-optic effect [csea, Apr 24 2012]

The frequently misunderstood Prandtl-Glauert singularity phenomenon (see link) makes compression waves visible. This is not directly related to visual sound, but one might hypothesize that under very specific conditions or with very intense sound, sound waves themselves would become visible in this fashion.

(I have personally witnessed Prandtl-Glauert clouds on a commercial airliner during takeoff on a humid day.)
-- egnor, Aug 10 2000, last modified Feb 22 2001

Audible frequencies are translated to visual patterns in some disco-type "atmospheric" displays, laser light shows and the like - HUD display goggles/glasses might be able to do the same thing, although directional detection might be a little tricky. Might be useful as an aid to the deaf, or just to relive your acid days - for sure you'll never again have to ask, "who cut the cheese!"
-- Scott_D, Aug 11 2000

[the thing] There's a word for people like that, who actually do experience different sounds as different colours. Anyone remember what this is?
The obvious question that follows from this is to ask whether people who have this ability are consistent - that is, if you have a strong experience of the colour brown when you hear moving furniture, does everyone who experiences a colour when they hear moving furniture experience the colour, even the same shade of brown?

[Thanks vincebowdren. Looked at the link - It seems that different synesthetes experience different colours for the same things]

[Egnor, did you see the link?]
-- hippo, Aug 11 2000, last modified Aug 17 2000

[bear] just came up with a name for this technology, as a typo in another thread.

-- jutta, Aug 24 2000

You can see sound with an oscilloscope.
-- Amishman35, Feb 15 2001

My daughter associates color with sound, vividly. You can ask her what color a word is, and she responds instantly. The color-word connections are interesting and relate to a blur between the sound of the word and its meaning. Like this since she first began to speak. Don't know if it is profound enough to qualify as synaesthesia (which I had never heard of until I read this page). She excels at painting, though.
-- bristolz, Feb 15 2001

My wife associates colors with words, too, but not due to their sound. For her, each letter has a color, and the color of the word is a result of the colors of the constituent letters (though usually not a straight blend of colors). She can often tell if a word is misspelled because it's the wrong color.
-- beauxeault, Feb 16 2001

Your wife's ability is much more interesting, I think.
-- bristolz, Feb 20 2001

Darn memepoolers. I wanted to post those links.
-- centauri, Feb 22 2001

If only I knew how to pronounce "Prandtl-Glauert"...
-- egnor, Feb 22 2001

Interesting thread...I hadn't seen it before so I'm glad it's been pulled up again today. I personally experience numbers as colours. I think/thought I was the only one who did this type of thing. I also see people with individual colours i.e. my friend Julie is a creamy, soft orange-pink shade and I, in a mirror, have a soft teal vibration. It's always been there although the intensity of individual colours can change day to day. I often find myself avoiding people of certain colours and drawn to others of different colours. I hear/see individual voices based on the colour of the speaker. Wait...this is all bizarre now that I have put it down in the men in white jackets to come and get me.....
-- Susen, Feb 22 2001

What is a "puce vibration"? I don't see it mentioned in the links.
-- Susen, Feb 22 2001

Skip it, susen. It was stupid.
-- centauri, Feb 22 2001

Wait a second: Wouldn't a car with a booming stereo obscure everything around it in a gaseous cloud of sound? Sounds dangerous.
-- mrthingy, Feb 23 2001

...and that would be a bad thing?
-- hippo, Apr 10 2001

Especially good info for bristolz and beauxeault
-- emdee2k, Aug 08 2001

Kids tend to exibit some synesthesia until about age six, at which time it goes away. I'd be intrested in bristolz's kid's age.
-- protean, Aug 08 2001

She is 9
-- bristolz, Oct 17 2001

Microsoft Media Player "Visualisations"
-- pashute, Sep 30 2002

The word //glee// sure is the color of orange sherbert in my mind.
-- _Mowgli_, Nov 11 2002

I thought this deserved being revisited in light of recent work at NPL. [link]
-- csea, Apr 24 2012

random, halfbakery