Make a Fossil Activity
Name: __________________________
3rd Grade PSI
Lab Question:
What is the difference between a cast and a mold?
Before You Begin:
Describe how a fossil is made from an imprint.
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Describe how a fossil is made from mineralization.
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www.njctl.org
3rd Grade PSI
Biological Evolution
Purpose:
Fossils give us information about organisms and their
environments from previous eras. Some fossils are created as
imprints and some are created due to mineralization. The results
of each process is different. In this lab, you will compare cast and
mold fossils.
Materials:
 Clay
 Paper plate
 Petroleum jelly
 Plaster of Paris
 Water
 Spoon
 Cup
 Items to be fossilized
Procedure:
1. Follow your teacher’s directions for making the mold.
Compare how the mold looks and feels compared to the
original item.
2. Follow your teacher’s directions for making the cast.
Compare how the cast looks and feels compared to the
original item.
Questions:
1. Draw a picture of the mold and the original item below.
www.njctl.org
3rd Grade PSI
Biological Evolution
2. Draw a picture of the cast and the original item below.
3. How are casts and molds similar? How are they different?
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www.njctl.org
3rd Grade PSI
Biological Evolution