Re: World's noise

[brian whatcott <inet@INTELLISYS.NET>]

Muhsin,
a good way to get started  on Fourier analysis is by playing with
a DOS package called "Plotter" written by a research engineer
called Robert Lindsay Wells who is at UTexasTyler last I heard.

I picked a Czech URL in hopes it might be a little easier for you
 to download from there. Being DOS, it is not quite so huge as a
typical Microsoft Windows based article - about 300 kilobytes,
I think.
<http://www.abf.cz/software/shareware/ostatni.html>

He offered it on a shareware basis for some time so people could
try and buy at about $25 but I think he is no longer actively
selling it.
You generate an ascii file with two columns of data
as input to the plotter package. This is not hard to get into.
Give it a try. You could try a sound waveform, or even a
seismograph record.

If you have access to the web, there is a reasonable description
of waveform analysis using the Fourier transform here:
<http://www.dataq.com/applicat/articles/an11.htm>

As your last message was repeated in html mode (which it is better
to stop) I expect you have a Web browser and access.


Among the many, many FFT applications that show up on a web search
are the following:
FFTW
Frito's FFT  c library, so not as usable as you'd probably want.
 This has references to other URLs
<http://www.fftw.org/>

At the advanced level:
Astronomical Image Processing on the PC with PCIPS
<http://cadcwww.dao.nrc.ca/ADASS/adass_proc/adass3/papers/smirnov2/smirnov2.
htm>

And for the folks who really want to use the professional Earthtide
analysis tools:

TSOFT
Earthtides free DOS
<http://www.astro.oma.be/SEISMO/TSOFT/tsoft.html>

Hope these pointers help.

In answer to your second question, "How can a temperature be
a million times cooler than some other temperature?",
this is expressing the idea in a poetic way, that each halving
of temperature towards the absolute zero of temperature
0 Kelvin or about -273 degrees C, is about as difficult to produce
as the previous halving; particularly at the lowest temperatures.

It also expresses the idea that expecting to achieve exactly 0K
is unlikely, when arriving at 1mK from 2mK is tough.

Brian W


At 17:15 9/8/01 +0300, Muhsin Ogretme wrote:

> I am from Istanbul, Turkey. Listening to a rock is a very good idea for
> a project work with my 6th graders, I think. I reckon as you suggested
> we'll need a sensitive microphone, and a tape recorder, with a proper
> installation. But I don't have any idea how to use fourier analysis for
> the data to be collected.
>
>
> BTW, I was reading the article at
>
> http://www.jpl.nasa.gov/releases/2001/heliumwhistle.html
>
> The first sentence nn the 5th paragrah was strange. What is temperature
> "nearly 1 million times colder than room temperature"?
>
> brian whatcott wrote:
>
> > Muhsin, you have probably been following the interesting debate about
> > ocean tides, and the prolate shape the ocean surfaces would adopt,
> > if not for the many complicating factors which exist.
> >
> > You will have read that not only do the gravity and spin and rotation
> > gradients affect the water, but also the Earth itself.
> >
> > It is a short step from here to ask, can I actually hear a circadian
> > rhythm and its second harmonic?
> >
> > This seems like the kind of adventurous earth physics experiment that
> > might appeal to young students: the concept is easy to grasp:
> > if I place a microphone in intimate contact with a deep rock formation
> > perhaps in a quiet mine, can I capture evidence of an earth tide?
> >
> > A first step might be a tape recorder setup with a low noise pre amplifier
> > perhaps. You might well find that the slow grinding of the Earth flex
> > is not perceptible by this means.
> >   But the next step is to collect a sound sample over a period of many
days.
> > One would not need to sample very frequently, perhaps three times an hour.
> >
> > There are college physicists who I am sure would help with analyzing
> > this sort of time series - a fourier analysis of 1024 such samples over a
> > two week period might be gratifying, to start with.
> >   There is a possibility for a library search for prior work in this area.
> >
> > Is this a project which might be of interest to your students? Would you
> > need help with equipment? Where are you located?
> >
> > Brian W
> >
> >
> >
> > brian whatcott <inet@intellisys.net>  Altus OK
> >                Eureka!

brian whatcott <inet@intellisys.net>  Altus OK
                Eureka!