[meteorite-list] sample meteorite specific gravities

From: David Gunning <davidgunning_at_meteoritecentral.com>
Date: Sat, 21 May 2011 19:53:21 -0400 (EDT)
Message-ID: <54766.74.209.45.243.1306022001.squirrel_at_webmail.fairpoint.net>

Any scale that measures precisely can be used for determining specific
gravity. First thing is to weigh the specimen, this is referred to as
the "air" weight. Next, the same specimen is weighed while submersed
under water, this is referred to as the "water" weight.

Subtracting the "water" weight value from the "air" weight value leaves a
result, which is then divided into the "air" weight value, equaling the
specific gravity value.

Say, for example, 4 (air) minus 1.5 (water) equals a result of 2.5. The
resulting value of 2.5 divided into the air weight of 4, equals the
specific gravity of 1.60 for the specimen in question.

The actual scale that I use for these measurements is an electronic type
scale which can measure exacting weights to hundredths of a carat or a
gram. But you don't have to spend big bucks for an electronic scale that
will weigh hundredths of a gram; any precise scale will work well enough.

Hope this explanation helps.

David Gunning



> Would you mind giving us a glimpse of your direct read scale. I'd be
> interested in seeing it and learning a little more about it and how it
> works.
>
> Mike
>
> On May 21, 2011, at 12:23 PM, David Gunning wrote:
>
>>
>> Hi All,
>>
>> Allende, cv3.2; direct measured specific gravity: 3.47
>>
>> Travis County, (a) H-5; direct measured specific gravity: 3.40
>>
>> Gao, H-5; direct measured specific gravity: 3.31
>>
>> Tatahouine, dio; direct measured specific gravity: 1.43
>>
>> Lahoma; direct measured specific gravity: 2.44
>>
>> El Hammami, H-5; direct measured specific gravity: 3.32
>>
>> These specific gravity values are arrived at utilizing the time
>> honored Archimedean method, where distilled water at room
>> temperature has an estimated approximate value of 1.0.
>>
>> Some of these direct measured specific gravity values may be at
>> odds
>> with previously published specific gravity values by other sources.
>>
>> Porosity values have been observed by soaking each specimen in
>> distilled water for 24 hours and taking that into the final account.
>>
>> Respectfully submitted,
>>
>> David Gunning
>>
>>
>>
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>
Received on Sat 21 May 2011 07:53:21 PM PDT