P.S. 101
Unit: Fossils
Lesson 2: Identifying Fossils


Aim:    Students will learn to identify the kinds of fossils and how they were formed.


To locate specific information on the formation of fossils.
To transfer this information into notes for study.
To construct a chart to display the information gathered by this research.

Vocabulary:    mold, cast, trace, true form fossils

Materials:    pictures of various fossils, markers or crayons, plastic dinosaur figures, Crayola Model Magic, leaves, twigs, Science, Barman et al., Addison-Wesley Publishing Company, Menlo Park, 1992.


1. Display pictures of fossils using this link:
See pictures of fossil formations from this site:

Hear dino sounds, look at dinos in motion, join a dig, build your own fossil, discover fossils in parks, and see fossil guide.
Visit the Museum of Paleontology at Berkeley. Discover the history of life.
2. Point to each fossil in the picture and ask students to study the fossil and try and form a hypothesis as to how it was formed.
3. List guesses on database sheet.
Type of Fossil and Student's Picture
Actual Formation
true form


1.    After students have examined each picture, ask them to compare and contrast fossils. How are they alike? How are they different?
2.    Read pages 241-243 in Science. Make notes of the important facts they have discovered about the formation of these different kinds of fossils. Add information onto the database chart above in the column labeled "Actual Information."
3.    Use the data in the actual formation column to evaluate and amend student hypotheses.
4.    Students draw examples of each type of fossil in column 1 on the database chart.
5.    Students will construct models showing casts, molds, and true form fossils:
                        a.     Using Crayola Model Magic make an impression with twigs, leaves, casts of fossils, and plastic dinosaur figures to show trace fossils.
                        b.    Remove the twigs, leaves, etc. and fill with plaster of Paris to show cast. Allow to harden and paint.
                        c.    Leave the twig or leaf preserved in the Model Magic to demonstrate true form fossil.
                        d.    Make impression with leaves, twigs, etc. and remove object to demonstrate cast fossil.

Summary:        Students restate in a short paragraph how each type of fossil is formed.


Additional Resources:
lesson plan on how to create a cast fossil
Students develop concepts of molds and casts in this lesson plan.
Fossil catalog, links to other fossil related sites
photos of fossils from various periods