Wikipedia:Reference desk/Archives/Science/2012 October 11

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October 11

depth of voice and time of day

Why is my voice so much deeper in the mornings, not to mention when I have a cold? I've checked, and it's not my imagination. I've been out of bed for only a little while, and I'm half an octave lower than last night. IBE (talk) 09:27, 11 October 2012 (UTC)

This is a possible medical condition. We don't give medical advice here, so see a doctor. Floda120.145.20.231 (talk) 12:59, 11 October 2012 (UTC)

I think I have a fair idea of the rules. It would be a strange medical condition. It is a fairly common observation in the case of a cold that the voice drops a fair bit. I used myself to show that I had double checked that it wasn't my imagination. IBE (talk) 13:39, 11 October 2012 (UTC)

Googling for the lower morning voice portion finds a lot of singing sites that primarily suggest that your vocal chords are, after a night of disuse, relatively slack and thickened (analogous to taking the tension out of a guitar string). I have anecdotally observed similar effects when I have a cold, but I don't know what the relevant mechanism there would be. — Lomn 14:26, 11 October 2012 (UTC)

There's some discussion of this on the Straight Dope Forum, where the consensus seems to be that the voice is lower during a cold mainly because of swelling of the vocal cords. AndrewWTaylor (talk) 15:21, 11 October 2012 (UTC)

Just personal experience, but the phlegm coating the vocal chords seems to play a role in lowering the lowest attainable pitch, since a good rinse immediately raises it bu a couple of notes.Would a vibrating sting of a certain length and tension sound a lower pitch it it had more mass per unit length? The phlegm or coating could provide that extra mass. Edison (talk) 15:47, 11 October 2012 (UTC)

It would, that's why guitar strings are different thicknesses. The note a string sounds is a combination of its thickness, composition, length, and tension. They all play a factor. --Jayron32 15:52, 11 October 2012 (UTC)

Searching the web for morning deep voice finds some discussion suggesting that in the morning you are unaffected by the day's mental stresses (don't we all get whiny when we get stressed), and gravity hasn't been shaping your height and your vocal cords.88.112.36.91 (talk) 16:42, 11 October 2012 (UTC)

The gravity one is quite interesting: I thought of this, but gravity should shrink your neck (well, slightly) making it a bit thicker, and hence your voice slightly deeper. But I like the whiny voice suggestion. IBE (talk) 17:19, 11 October 2012 (UTC)

Approximately how much lower does one's voice usually go during a cold? Double sharp (talk) 13:07, 14 October 2012 (UTC)

Mine dropped half an octave last time. Strangely, it persisted for about half a day after the cold had basically worn off, so maybe it has more to do with inflation than mucus. IBE (talk) 00:58, 15 October 2012 (UTC)

Chemical Equilibrium Expression

I have a series of chemical reactions for which I'm trying to develop an equilibrium expression.

(1) A <> B + C

(2) (x)*B <> D

(3) (y)*D <> D

(4) D + A <> B + C

My intuitions says that:

K = K1([B][C])/(A + K4*D*A) + K2(D)/(([B]^x)+ K3([D]^y))

But I can't find a good set of rules to derive this. Thanks for any help that can be offered. —Preceding unsigned comment added by 134.20.11.89 (talk) 15:50, 11 October 2012 (UTC)

This must be obvious but I'm missing the meaning. If A<> B+C then how can D+A <>B+C? What does (y)*D <> D mean? Wnt (talk) 01:00, 12 October 2012 (UTC)

Not addressing the question itself, but for the benefit of clarity to everyone else, I assume "<>" is the equilibrium sign, which can be displayed directly on WP using the {{eqm}} template. So "A ⇌ B + C" displays as "A ⇌ B + C". DMacks (talk) 01:09, 12 October 2012 (UTC)