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I'm no expert on solid-state fossil matrices, but... We had a class some
years ago that used plaster of paris cookies which kids had to dig
fossils out of. Here's why we had to scrap it:

Timing. Once you put the fossils (we just used shark teeth, uber-cheap)
in the plaster, you had to wait, IIRC, a couple days for the stuff to
dry or it would be too soft and too easy to get the fossil out of. But
if you kept the things around too long, they got rock hard and nearly
impossible to get through. I discovered this when, like a good little
outreacher, I tried whipping up a large supply of cookies ahead of
time...

Has the addition of saqnd solved this problem, Wendy? If so, I'd love to
hear this recipe, too. We've had some success with an exhibit where we
used used a sand/wax matrix. Worked ok, though it was a little smelly to
create. I'll see if I can find that recipe.

Jonah Cohen
Outreach & Public Programs Manager
The Children's Museum 


Double, double, toil and trouble
Particle accelerator CERN
And space telescope Hubble

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