| Author |
Message |
Rune Allnor
Guest
|
 Posted:
Mon Dec 13, 2004 3:46 pm Post subject:
Homework for the hollidays |
|
|
| Quote: | Rune,
Here's a reference for you:
D.P. McKenzie and R.L. Parker, " On the Note Emitted from a Mug while
mixing instant coffee", Proceedings of the Cambridge Philosophical
Society, V65, 365 (1969)
Yes, it's a real one.
Ciao,
Peter K.
You can't be serious...!?
Oh yes, Peter is serious. I looked the article up in the databases,
and it exists. I even ordered it. The library software complained
about "not being able to verify the journal", so it remains to be
seen if I can get a copy.
straight face
And people complain about university researchers not taking their
job seriously...?!
/straight face
Rune
|
The article arrived today. These guys really did a thorough job!
They tested with several types of powder, with hot and cold liquids
and with fast and slow stirring.
I like one very laconic sentence in the discussion of exactly
what physical effect causes the phenomena:
"Appeals to the non-linear motion of the fluid motion
fail because the coffee does not need to be agitated
violently."
I can just imagine these people trying this effect out...
Seriously, the conclusion on what causes the effect, is that
a body of water that contains air bubbles becomes a lot more
compressible than pure water. Compressibility is related
to the acoustic wave velocity, and the papers states without
proof that water containing 1% (volume) of finely distributed
air, has a wave velocity 30 times lower than pure air. Which
would explain the change in pitch as the air is released from
the liquid.
Rune |
|
| Back to top |
|
 |
Peter J. Kootsookos
Guest
|
| Posted:
Mon Dec 13, 2004 5:13 pm Post subject:
Re: Homework for the hollidays |
|
|
"Rune Allnor" <allnor@tele.ntnu.no> wrote
| Quote: | The article arrived today. These guys really did a thorough job!
They tested with several types of powder, with hot and cold liquids
and with fast and slow stirring.
|
Glad you liked it. :-)
It has to be one of the "classic" papers of all times.
Ciao,
Peter K. |
|
| Back to top |
|
|
Eric Jacobsen
Guest
|
| Posted:
Mon Dec 13, 2004 10:38 pm Post subject:
Re: Homework for the hollidays |
|
|
On Mon, 13 Dec 2004 07:13:07 -0500, "Peter J. Kootsookos"
<p.kootsookos@remove.ieee.org> wrote:
| Quote: | "Rune Allnor" <allnor@tele.ntnu.no> wrote
The article arrived today. These guys really did a thorough job!
They tested with several types of powder, with hot and cold liquids
and with fast and slow stirring.
Glad you liked it. :-)
It has to be one of the "classic" papers of all times.
Ciao,
Peter K.
|
I have a friend at Cambridge, I'll ask whether I can get a copy of
this.
Meanwhile, I did try this with a couple pints of Boddington's with
mixed results. Maybe Nello's just has low-quality drinking glasses or
something, but if there was a change in the tone it wasn't very
detectable.
Naturally, this just means that more data collection is necessary. ;)
Eric Jacobsen
Minister of Algorithms, Intel Corp.
My opinions may not be Intel's opinions.
http://www.ericjacobsen.org |
|
| Back to top |
|
|
Rune Allnor
Guest
|
| Posted:
Tue Dec 14, 2004 11:21 am Post subject:
Re: Homework for the hollidays |
|
|
Peter J. Kootsookos wrote:
| Quote: | "Rune Allnor" <allnor@tele.ntnu.no> wrote
The article arrived today. These guys really did a thorough job!
They tested with several types of powder, with hot and cold liquids
and with fast and slow stirring.
Glad you liked it. :-)
It has to be one of the "classic" papers of all times.
|
It certainly must be.
The whole instant coffee thing came up during a coffe break
here at the department, and the article was very well recieved.
One of the older professors commented after I had shown the paper
that "It's a fun paper, but how on earth does one FIND such a
thing?" My excuse was that somebody mentioned it on comp.dsp.
Now, once the question has been brought to one's attention...?
Rune |
|
| Back to top |
|
|
Rune Allnor
Guest
|
| Posted:
Tue Dec 14, 2004 11:34 am Post subject:
Re: Homework for the hollidays |
|
|
Eric Jacobsen wrote:
| Quote: | On Mon, 13 Dec 2004 07:13:07 -0500, "Peter J. Kootsookos"
p.kootsookos@remove.ieee.org> wrote:
"Rune Allnor" <allnor@tele.ntnu.no> wrote
The article arrived today. These guys really did a thorough job!
They tested with several types of powder, with hot and cold
liquids
and with fast and slow stirring.
Glad you liked it. :-)
It has to be one of the "classic" papers of all times.
Ciao,
Peter K.
I have a friend at Cambridge, I'll ask whether I can get a copy of
this.
Meanwhile, I did try this with a couple pints of Boddington's with
mixed results. Maybe Nello's just has low-quality drinking glasses
or
something, but if there was a change in the tone it wasn't very
detectable.
|
If you were in a pub, the drinking glasses are usually treated
so that they completely shatter, should they break. I think it
has something to do with certain violent episodes where glasses
have been smashed and large pieces of glass have been used as
weapons. I have found that drinking glasses in pubs tend to be
very bad resonators. I suspect it's because of this preparation
of the glass.
Now, having seen the line of arguments in the article, I would
expect beer to be a poor example for the changing pitch effect.
If the changing volume of air trapped in the liquid indeed is
the cause of the changing pitch, you will only hear a change
if the air bubbles escape when the liquid is stirred
_and_no_new_air/gas_is_introduced_ to the liquid. In beer and
carbonated sodas, new new bubbles form all the time.
| Quote: | Naturally, this just means that more data collection is necessary.
;) |
That's the predicament of the experimentalist: To draw conclusions
on a too weak data basis. The beer/soda hypothesis above needs
experimental verification.
Rune |
|
| Back to top |
|
|
Richard Owlett
Guest
|
| Posted:
Tue Dec 14, 2004 11:58 pm Post subject:
Re: Homework for the hollidays |
|
|
Rune Allnor wrote:
| Quote: | [snip]
That's the predicament of the experimentalist: To draw conclusions
on a too weak data basis. The beer/soda hypothesis above needs
experimental verification.
|
Perhaps some mead is required to establish a 'no bubbles' baseline ;] |
|
| Back to top |
|
|
|
|
|
|
FAQ
Memberlist
Register
Profile
Log in to check your private messages
Log in