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Sandra,
You are correct when you say standard non-mercury thermometers are not as accurate. All you have to do is look at a bunch and note the 2-3 degree
difference in readings. I’m sure the certified ones are better, but we can’t afford them for student use. Another problem no one has mentioned is that the column in spirit thermometers tends to separate. We lose more from that than breakage. We do use
the spirit thermometers for most of our work, but I do wonder about the actual danger of the occasional broken thermometer – cleaned up as much as possible, of course. Mercury is certainly hazardous, metallic mercury less so than some other forms, but yet
the push for using light bulbs containing Hg is incessant. Mercury in thermometers is an easy target. And, for associations and governing bodies the ease of the target is often more important the actual danger.
Hope everyone has a Happy Thanksgiving,
Kay
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU]
On Behalf Of Koster, Sandra
Sent: Monday, November 25, 2013 6:41 PM
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: Re: [DCHAS-L] Marketing the Conversion to Non-Hg Thermometers
It has been my experience that the non-mercury thermometers we got to replace our mercury ones some years back are considerably less accurate than mercury thermometers. For example, we do a steam distillation
of limonene/water from orange peels and when we switched we routinely got b.p.'s above 100 degrees. The true result is a bit under 100 degrees and that is a concept we are trying to get across. As another writer mentioned, digital is better. For routine
use in our organic teaching labs we use a thermometer like the Thomas traceable lollipop shockproof/waterproof thermometer, 8" stem except that I don't think we get it from Thomas. You can find a picture on Amazon..com. Then we get
much better numbers in distillations and m.p.'s. I just wish the stem was a bit thicker to fit in our thermometer adapters better but we make do with some o-rings for distillations and a copper sleeve insert in our MelTemps for better heat transfer.
Sandra Koster
Senior Lecturer
University of Wisconsin-La Crosse
On Mon, Nov 25, 2013 at 1:45 PM, Dan Blunk <blunk**At_Symbol_Here**ucsc.edu> wrote:
Colleagues,
I’m looking for comparison data / recommendations I might use to assuage academic researcher anxiety with respect to swapping their mercury thermometers
for spirit thermometers.
Reluctance to give up Hg thermometers is often rationalized by claiming spirit thermometers aren’t as accurate or aren’t appropriate for as many applications
as a mercury-filled thermometer.
I would appreciate suggestions on where I might find performance-based support for spirit-filled thermometers.
I have information regarding comparisons of potential exposure health risk, spill clean-up expense and environmental contamination.
Thanks for your help in finding performance-based support for using spirit filled thermometers rather than mercury filled thermometers,
Dan
---------------------------------
Dan Blunk PhD, REA
831.459.3541
Environmental Programs Manager
Environmental Health & Safety Office
University of California Santa Cruz
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