Re: pinhole Thermometers

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From: Geoff Ruth (gruth@leadershiphigh.org)
Date: Thu May 19 2005 - 20:40:40 PDT 

Message-Id: <p06110403beb30acd7293@[192.168.1.102]>
Date: Thu, 19 May 2005 20:40:40 -0700
From: Geoff Ruth <gruth@leadershiphigh.org>
Subject: Re: pinhole Thermometers

Casey --

The way that I've dealt with this is to cool acetone or isopropanol
alcohol with dry ice to a low temperature, and then put the
thermometers in the cooled liquid. Then shake the thermometer, so
that you jar any air that may be trapped in the thermometer bulb.
Sometimes you have to do this, let them heat up to room temp again,
and then repeat.

Sometimes just quickly shaking the thermometer in an arc will force
the liquid back together.

I haven't tried this, but I've read you can also heat them till the
thermometer alcohol rises all the way to the top. Then lightly tap
the thermometer to jar any gases. Don't heat up too much b/c you can
overfill the "expansion" chamber at the top and crack the thermometer.

Here's some links:
http://www.hbinstrument.com/faq.php#2
http://www.chem.purdue.edu/chemsafety/Chem/HgFAQ.htm#part7

Good luck,
Geoff

>I just found a bunch of old blank thermometers that I'd like to use
>for a temperature scale project. Unfortunately, many of them have
>air bubbles which break up the column of red alcohol.
>
>Is there an easy way to fix this, to recombine all the alcohol into
>one continuous column? It seems like some regimen of high-ish
>temperature or cold-ish temperature might work, but then again,
>maybe that's what got the bubbles in there in the first place...
>thanks!
>
>--Casey
>
>
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