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02 December 2009 @ 10:15 am
Ask lazyweb: the sound of water  
Why do hot and cold water sound different?
I'm feeling: curiouscurious
Rowan: Housemzrowan on December 2nd, 2009 03:17 pm (UTC)
Hot water causes pipes to expand?
harimad on December 2nd, 2009 04:27 pm (UTC)
Hot water contains more air and particulate matter?
Beowabbitbeowabbit on December 2nd, 2009 04:52 pm (UTC)
They do? News to me! You mean water coming out of a tap and hitting a basin?

I would imagine there would be differences in the turbulence of the flowing water, maybe. But I bet there are bigger differences in the pressure of the water coming straight from the water main versus the pressure of the water coming from the water heater.
ruthless compassion: martini handsaroraborealis on December 2nd, 2009 05:08 pm (UTC)
I can tell the water is hot in my shower because the sound changes, but I'm not sure if it's the sound of the water in the pipes or the sound of the water splashing that's different.

I was reminded of this this morning, though, when I filled my mug with hot water from the water cooler for tea and it sounded different in the cup from when I fill it with cold water to drink straight.
(Deleted comment)
Ellen: with T.keyne on December 3rd, 2009 01:06 am (UTC)
You win!
sarahshevettsarahshevett on December 2nd, 2009 05:31 pm (UTC)
motive nuance: spidermotive_nuance on December 2nd, 2009 06:02 pm (UTC)
It's not a property of the water — it's a property of the pipes. When the hot water hits the pipes, they expand, changing both the water's rate of flow and the pipes' harmonic resonance frequencies.
David Policardpolicar on December 2nd, 2009 07:08 pm (UTC)
I'd never thought about it until you asked the question, but thinking about it now... I think they sound different in my house because they run through pipes differently (and run through different pipes, in some cases).
Barryinthatoneway on December 2nd, 2009 10:50 pm (UTC)
I think your shower sounds different because of the steam. When your water gets hot, it dumps a lot of moisture into the air, markedly changing its density. This will change the pitch of any sounds travelling through it, just like the way your voice changes if you breath helium.

Edited at 2009-12-02 11:05 pm (UTC)
Stunt Double for the Patriarchystarphire on December 3rd, 2009 02:49 pm (UTC)
I'll add another random theory to the mix, just because nobody else mentioned it. Hot water from the heater tank has more dissolved gas in it - you know how it comes out cloudy-looking?
That might have an effect somehow. :)
harimad on December 3rd, 2009 06:51 pm (UTC)
Heaven forbid I don't point this out!
Unless "air" /= "dissolved gas" (and in this crowd I'm sure someone could come up with a reason that it isn't), it has been mentioned above.

tooting my own horn
Stunt Double for the Patriarchystarphire on December 4th, 2009 01:43 am (UTC)
Re: Heaven forbid I don't point this out!
Hmm, yeah I missed that comment somehow. And I must have looked at the whole set of comments at least twice before commenting. No slight intended, sorry.