Method 2: Students run their controlled experiments.
After completing all these preparations, students finally are ready to
conduct their experiments. Below is an example of an experiment a student
might conduct to test this hypothesis:
Organisms with soft body parts are equally likely to
form fossils as those with harder body parts.
The student:
- first looks at fossil samples to get a sense of the types
of organisms or parts of organisms that can become fossilized. The
student records his or her observations in a notebook or journal.
- gathers organisms to test for the experiment, such as one
unpeeled shrimp, one cooked chicken wing, one clamshell, one green
leaf, and one small twig.
- examines the organisms and predicts which might decompose
quickly and which more slowly. The student also records reasons for
his or her predictions.
- puts each of the organisms into a small zip-closing plastic
bag and double-seals each bag with masking tape. The student labels
the bags with the time, date and initials and puts the bags into a
closet or other dark area.
- checks on the organisms each day over the course of two weeks
and records observations about decomposition in a notebook or journal.
These observations can also include photographs and/or drawings.
- reviews his or her observations and draws conclusions about
which organisms are most likely to become fossils, due to slow rates
of decomposition.
- uses data to support or refute the hypothesis.
No matter what experiment your students are running, they should take
photographs, make sketches, keep notes, and record observations throughout.
Observations should include detailed descriptions or measurements of what
happened when they manipulated their independent variables.
Guide students to record their observations in their science fair journal.
Science Journal Downloads:
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