PSN-L Email List Message

Subject: Re: Diamagnetic materials variation
From: Karl Cunningham karlc@.......
Date: Sun, 10 Oct 1999 09:59:57 -0700


Meredith --

A couple of comments:

At 09:39 PM 10/9/99 -0700, you wrote:
>Bismuth
>is one of those, -10.5 (s)on one, and -280.1 (I)
>on another.  The (s) and (I) is not defined. A
>number of items on the list also exhibit a
>variation of values.  Tin is another one, with
>+3.1 (White tin)to -37.0 for (gray tin).

I don't know for sure, but I think the different susceptibilities for
bismuth and tin are for different crystal structures.  Many materials'
molecules can come together in more than one way, depending on the
conditions present (temperature, pressure, rate of cooling, etc.) while the
crystals are forming.

>Purity also doesn't guarantee a uniformity in
>diamagnetism.  I have some carbon rods with
>statements of purity probably going beyond
>99.999%, with impurity up to some 4 parts per
>million, and yes, their diamagnetism varys
>from one rod to the next....some obviously
>weaker than another in diamagnetism "levels".
>Still; these aren't really any better than
>some 3 other levitation carbon brush assemblys
>I have. 

Many properties of compounds can be changed dramatically by *very* small
changes in impurities.  I don't know if this is the case here, but I
wouldn't rule it out.

>Bob reports testing some aluminum sulfate, but
>while diamagnetic, it wasn't near as dramatic
>as the listed value of -323.0, and, he says:
>"but no obvious "strong" diamag apparent -
>prob. less then Rochelle salt, quartz & few
>others I tried."    Sodium cloride is listed at
>-30.3 on the 1988 list, quartz is not listed.

For quartz, see SiO2 (listed under silicon as silicon oxide in the chart).
That is the chemical compound of quartz, but again is the issue of matching
the crystal structure.

>Now...it sure would be nice if levitation
>co-operated over the years; we might all be
>running levitation seismometers now.... 

I also wish that springs would be a bit more cooperative with regard to
temperature effects.


Karl Cunningham
La Mesa, CA.
PSN Station #40
karlc@.......

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Larry Cochrane <cochrane@..............>