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ISEN-ASTC-L is a service of the Association of Science-Technology Centers
Incorporated, a worldwide network of science museums and related institutions.
*****************************************************************************
When we had Strange Matter here a couple of years ago, I used Epsom
Salts (Magnesium Sulphate) to form crystals rapidly.
We dissolved as much of the salt as we could in water warming on a
hotplate, and then dropped the solution on the surface of an old
fashioned overhead projector. The crystals formed instantaneously and a
whole room had a great view on a screen as the crystals formed.
Afterwards, you could lift the transparency sheet and pass it around and
to see the crystals up close.
We were planning to use this as a floor demo but keeping the solution
hot enough was a problem - we were very concerned the public might get
burned. It worked well in volunteer training, and I could see it working
in a classroom.
-----Original Message-----
From: Informal Science Education Network
[mailto:[log in to unmask]] On Behalf Of Jane Snell Copes
Sent: Thursday, August 16, 2007 10:33 AM
To: [log in to unmask]
Subject: Re: Quick Crystals
ISEN-ASTC-L is a service of the Association of Science-Technology
Centers
Incorporated, a worldwide network of science museums and related
institutions.
************************************************************************
*****
I would avoid naphthalene either in solution or sublimed and
recrystallized. Here's a link to MSDS, indicating moderate health
and flammability hazard. OSHA exposure limit is 10 ppm, which is
quite low. If you can smell it, you're likely above the limit.
http://www.sciencestuff.com/msds/C2149.html
Sodium acetate and sodium thiosulfate 5-hydrate are both less toxic
and can actually be reused. That's my 2 cents' worth. Do you
realize computer keyboards no longer have a cent sign? Jane
--
Jane Snell Copes Science Outside the Box 651-357-3316 (cell)
Science Outside the Box is a tiny business that celebrates the
scientist in every one of us. I am a writer and teacher, and I have
fun with science every single day. I'm especially fond of designing
classes and science magic shows for kids and parents.
"To be an inventor, you need a good imagination and a big pile of
junk." Edison
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For information about the Association of Science-Technology Centers and the Informal Science Education Network please visit www.astc.org.
Check out the latest case studies and reviews on ExhibitFiles at www.exhibitfiles.org.
The ISEN-ASTC-L email list is powered by LISTSERVR software from L-Soft. To learn more, visit
http://www.lsoft.com/LISTSERV-powered.html.
To remove your e-mail address from the ISEN-ASTC-L list, send the
message SIGNOFF ISEN-ASTC-L in the BODY of a message to
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