ISEN-ASTC-L is a service of the Association of Science-Technology Centers
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In the past we have used a 8 to 1 sand Portland mix. This can set up
over night. Problem is the longer it sits the harder it gets so we look
to use the matrix within a few days. We use a 4" deep metal round pan
found at most auto supply stores, use a cooking spray as the release
agent, mix the sand and cement to a fairly dry consistency, press a thin
layer into pan, a layer of fossils (oysters, gastropods, shark teeth,
etc.), a layer of cement and on and on , like building a layer cake. Let
sit overnight or until set. Turn over and it should pop right out. We
then have the kids use pencil thick wood dowel sharpened in a pencil
sharpener as picks and disposable paint brushes.   

Clark Hancock
Exhibit & Collections Coordinator
Austin Nature & Science Center
301 Nature Center Dr.
Austin, TX  78746
(512) 327-8181 ext.14
(fax) (512) 327-8745
 
work schedule: Tues - Sat
 
"Big things that are distant too often take precedence over important
things right under the nose."
 -Roy Bedichek

-----Original Message-----
From: Informal Science Education Network
[mailto:[log in to unmask]] On Behalf Of Wendy
Derjue-Holzer
Sent: Thursday, January 03, 2008 10:06 AM
To: [log in to unmask]
Subject: matrix for fossil dig

ISEN-ASTC-L is a service of the Association of Science-Technology
Centers
Incorporated, a worldwide network of science museums and related
institutions.
************************************************************************
*****

Dear resourceful listserv members,

Can someone send me a recipe for a plaster of paris/sand matrix to use 
in our investigation cart "fossil dig"? The previous education director 
developed this fun activity but did not leave the recipe for the matrix 
(at least in all the places I looked). At present our fossils have 
already been "dug" so we need to freshen up and re-bury our fossils.

Thanks,
Wendy

-- 
Wendy Derjue-Holzer
Assistant Director of School and Teacher Programs
Harvard Museum of Natural History
(617) 495-5782
www.hmnh.harvard.edu

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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.

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