The Fossil Hunt:
Part 2: The Fossil Hunt
A Fossil Lesson Plan
This is a continuation of a lesson plan on fossilization. For part 1 click here or on the link at the bottom of the page that reads: The Fossil Hunt is part 2. Part 1, Fossilization, is here.
Notes for the leader/teacher:
We recommend that you say as little as possible in each lesson, giving
your students opportunities to think and express their own ideas.
Dialogue is included in bold and italics. Things you would do during the lesson are in CAPITAL LETTERS.
When the plaster has set up (30-60 minutes) you may begin the
excavation process, but you might want to leave it for a few days or
weeks. Then, when students return to it, they won’t have a memory of
which fossil is in which particular location. That will help make the
process of the fossil hunt even more realistic.
students have successfully completed their cleaning and identification,
set up a “museum” to show off their work. As fossils are taken home,
helping the students to set up their personal fossil collections is
particularly important. Collecting boxes are easy to come by and not
expensive. Student labels can be fixed to the box and the fossil cradled
on felt or cotton batting for protection from sliding or bumping on the
sides of the box. This last “collector’s” step is important closure for
the process, but is also the best inspiration for a lifetime of
Materials for the Fossil Hunt:
Preparation for The Fossil Hunt
- Prepared plaster of paris “rock” containing fossil specimens
“Chisels”: a metal butter knife or small screw driver set (ranging in
size from a tiny eyeglasses screwdriver to about an eight of
- Magnifiers of various types. These should be mounted so
the hands can stay free and working while looking through the
magnifiers at the fossil being removed
- Small bottle of vinegar with an eyedropper
- Clear nail polish
the lesson, remove the solid plaster of paris from the aluminum tray.
Have enough tools set up so a group of four students can share a
complete set. You might begin your lesson as follows:
rock in front of you is ready for the painstaking process of removing
fossils from it. The paleontologist who sent these to us needs your help
to carefully expose or remove the fossil. Since the fossil could be
fragile and easily damaged, we need to do this with a great deal of
care. The slightest chip in the work place could ruin the fossil we are
trying to expose.
paleontologists are working at a dig site, they might see just a small
part of a fossil sticking out of the rock formation or even just an
impression above the ground that would lead them to suspect a fossil was
contained in the rock at that location. The
first step of the fossil hunt is to decide where the fossil might be
hiding. Look at your rock to see if there are any bumps or ridges that
might indicate a fossil burial. ALLOW STUDENTS TIME TO
DECIDE WHERE THE FOSSIL COULD BE HIDDEN BENEATH THE SURFACE. HELP THEM
TO USE A PENCIL TO OUTLINE THE AREA. BUMPS OR IRREGULARITIES IN THE
SURFACE ARE TYPICAL CLUES.
- Once you decide
where you want to start your dig and have marked it with a pencil, use a
metal butter knife or scraper to gently scrape off the top layer of
rock just outside the pencil lines. As
you work, you may begin to see the edges of the fossil. Carefully scrape
around the edges until you think you have a good outline of the fossil.
IT WILL TAKE SOME TIME FOR THE FOSSIL TO REVEAL ITSELF.
IT IS IMPORTANT FOR STUDENTS TO REMOVE THE MATRIX A LITTLE AT A TIME
USING A SCRAPING TECHNIQUE. IN THIS EXERCISE, YOU WON’T NEED TO USE ANY
CHIPPING WITH HAMMERS. THE FOSSIL MAY STAY EMBEDDED IN THE ROCK
MATRIX, USING THE MATRIX AS A SORT OF READY MADE STAND. IN THIS CASE,
THE STUDENT WOULD CLEAN A NEAT “TROUGH” AROUND THE EDGES OF THE FOSSIL,
AND THEN CLEAN THE SURFACE OF THE FOSSIL. ALTERNATIVELY, THE STUDENT CAN
WORK AT REMOVING THE FOSSIL ENTIRELY. THIS MAY TAKE A BIT LONGER, BUT
IT WILL ALSO GIVE THE OPPORTUNITY TO TRY SOME ADDITIONAL TECHNIQUES FOR
REMOVAL. SEE #5 BELOW.
- Next use a brush
to gently remove the “rock” that is covering the fossil. If some of the
rock is thick you can carefully scrape at it with a chisel. Be extra
careful, though, because you could chisel off a part of the fossil. STUDENTS
WILL CONTINUE WORKING TO REMOVE THE ROCK AROUND THE FOSSIL. THE
FOLLOWING ARE SOME SUGGESTIONS THAT IMITATE THE WORK OF THE
PALEONTOLOGIST IN THE LAB.
- If the fossil is
tightly embedded and scraping away the matrix seems too great a
challenge, you can use a mild acid solution to help dissolve the matrix
away. In the lab, paleontologists, protect the exposed parts of the
fossil from the acid by painting it with a special glue. STUDENTS
CAN IMITATE THIS PROCESS BY USING VINEGAR DROPS ON THE MATRIX AROUND
THE FOSSIL. SINCE VINEGAR IS SO MILD, THEY CAN EVEN USE IT RIGHT ON THE
FOSSIL TO REMOVE EXCESS MATRIX. ONCE MOST OF THE FOSSIL IS CLEANED, YOU
CAN HAVE THE STUDENT COAT THE FOSSIL WITH CLEAR NAIL POLISH TO IMITATE
THE PROTECTIVE GLUE COATING.
- The last step to
completing your fossil hunt is to note the type of fossil, date of
acquisition or discovery, and the location. Once your fossil is cleaned
and ready for display, make a small information card that shares the
name of the fossil, the geologic time period and the location where it
The Fossil Hunt is part 2. Part 1, Fossilization, is here.