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Plaster of Paris is Sticking? Help

Postby ritchiebrendan » Fri Feb 21, 2020 10:01 am

Hi, My son and I are doing the "Fantastic Fossilization! Discover the Conditions For Creating the Best Cast Fossils", but are having issues making the plaster of Paris casts. When we go to remove the plaster molds the soils and sands are stuck to the plaster making it difficult to judge the casts. Is there a way to make thesand and soil not stick?

[Project url: https://www.sciencebuddies.org/science- ... st-fossils]

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Re: Plaster of Paris is Sticking? Help

Postby EmmaGriffiths » Tue Feb 25, 2020 5:41 pm

Hi ritchiebrendan!

I’m glad you and your son are getting involved in this experiment! Fossils are always a fun subject to study.

The soil/sand may be sticking to the plaster of Paris because it is still wet. Letting it dry for a little longer may help.

It may help to use a paintbrush to gently brush off any sand or dirt. Another source recommends running the cast under water, but be careful if you decide to do this; the plaster of Paris will begin to deteriorate in water, especially if you don’t handle it with care.

This being said, it’s completely normal to have some sand or dirt sticking to the cast due to the nature of the experiment... after all, real fossils are never sparkly clean! The dirt/sand on your cast actually mocks real fossils.

I’ve found a link that may be helpful to you: https://www.michigan.gov/documents/dnr/Track_casting_382484_7.pdf. Hopefully this guides you in the right direction.

I wish you luck with your project! You can always let us know if you have any other questions or concerns.


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Re: Plaster of Paris is Sticking? Help

Postby HappyQuarantineParent90 » Thu Apr 09, 2020 4:12 am

How your presentation gone? I checked the link of your project! Awesome! You're an awesome parent

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