Temperature Change affecting pitch

[Richard Brekne]

Farrell wrote:

> If I remember my college chemistry, warm air holds more water molecules
> because it is at a higher energy state. That is, the air molecules are
> moving more rapidly, and thus can suspend more water molecules. As
> temperature drops, air molecule energy decreases and cannot suspend as many
> water molecules.
>

Thats only part of the story Terry... thats why I said that Newtons last post
was "in correct". Actually the above paragraph (basically identical to what
Newton said) is quite correct as far as it goes... its just that you have to
put that fact into the appropriate perspectives in order to really understand
what relative humidity is all about. Read my last post...read that stuff I sent
you, go out and make measurments both inside and outside and think it through.
Believe me you are not the only one to stumble a bit on this humidity thing. It
is confusing and easy to get mixed up. But thinking about it often enough will
make things clear in the end

>
> Terry Farrell
> Piano Tuning & Service
> Tampa, Florida
> mfarrel2@tampabay.rr.com
>
> ----- Original Message -----
> From: "Richard Brekne" <richardb@c2i.net>
> To: <pianotech@ptg.org>
> Sent: Tuesday, March 28, 2000 4:11 PM
> Subject: Re: Temperature Change affecting pitch
>
> Er.... this is not correct ????..
>
> Warmer air expands... true... but this simply makes more room for more
> H2O to be contained by it. You never experienced a 90% RH day at 35 ¤
> did you ??? Cold air "squeezes" humidity out and  RH goes down. Grin...
> generally cus it rains or snows it out.
>
> Course its more complicated really than this... Wind / Circulation comes
> into play... etc.. But I cant see how raising temperature in itself is
> going to lower humidity, unless there are absolutely no other
> contributing factors. True enough.. in a closed sealed container.. with
> a given RH and Temp, a raise in temp will lower RH simply because the
> air is now "capable" of holding more H2O then before. But real climatic
> conditions arent so simple.
>
> In Bergen.. We get real low RH readings when the temperature drops.. and
> in the summer.. It goes way up.
>
> Newton Hunt wrote:
>
> > Temperature and humidity are coupled together, raise temperature
> > and humidity lowers and visa versa.  Warmer air expands and
> > stretches the humidity as well.
> >
> > Your measurements need to accompany humidity readings as well to be
> > truly interesting.
> >
> > Go back to the lab and reexperiement.
> >
> > Nice having fun toys isn't it?
> >
> >                 Newton
>
> --
> Richard Brekne
> Associate PTG, N.P.T.F.
> Bergen, Norway

--
Richard Brekne
Associate PTG, N.P.T.F.
Bergen, Norway