California State University, Long Beach
From California Classroom Science, March 2005, CSTA, page
Permission to post from Laura Henriques
A federal judge in Georgia recently ruled to remove these
stickers from science textbooks:
This textbook contains material on evolution. Evolution
is a theory, not a fact, regarding the origin of living things.
This material should be approached with an open mind, studied
carefully and critically considered.
People claiming "it's just a theory" don't fully
understand the nature of science. Science educators can respond
in a couple ways. We can urge the sticker advocates to add additional
stickers saying "Atoms and gravity are theories, too!"
or we can do a better job teaching the nature of science.
Below are a few activities to help students better understand
key aspects of the nature of science. Scientists use the word
theory differently than the way it's used in everyday life. To
a scientist a theory is a well-substantiated explanation,
strong enough to be useful for making predictions. To the general
public a theory is merely a hunch (often lacking substantial
Check It Out! Using canceled checks to teach the nature
There are variations on this activity but all are similar.
Students are given a set of checks, from the same account, with
which to construct a plausible story about the people writing
the checks. As students see more checks, they change their story,
i.e., as new data becomes available, the explanation changes.
With one set of checks (resource #1, check set C) we see checks
from a checking account initially owned solely by Paul. After
a check to a jeweler, the account has two names, Paul and Leslie.
Other checks include one to a hospital, a doctor, and checks
to ballet school five years later and high school 13 years after
that. Most students conclude that a child was born-even though
they weren't present to witness the event.
Students using these checks invariably develop stories influenced
by their own lives and societal/cultural norms. As students gather
additional checks they either flesh out the details of their
story or they throw out their story and start again. This happens
when they get checks with different addresses (could there be
a divorce or a new family business?) or when they get the first
check related to children (hospital, ballet school, high school).
This activity models real science in many ways. Usually new data
add details to our understanding. We throw out our stories (theories)
only when the data leaves no other choice. Like real science,
students never know for sure if their story is true-but some
story lines seem more plausible and better supported than others.
Evolution is similar. Evolution is by far the most probable explanation
for current data and hence the theory that is accepted by the
Cubes, Footprints and C.S.I.
In 1998 the National Academy Press published a book titled Teaching About Evolution and
the Nature of Science. Several activities help
students understand evolution and the nature of science. It's
all available on-line (http://www.nap.edu/readingroom/books/evolution98/).
Students examine data, make inferences, hypothesize and see how
a theory is developed. As a result of activities where students
examine a series of footprints, and make predictions about the
hidden side on a set of cubes, students gain working definitions
for theory. [Also, see the Footsteps
in Time lesson on the ENSI site.]
A major objection to evolution is that no witnesses were present.
All the evidence we have to support evolution is indirect. The
check activity is a low stakes way to use indirect evidence in
developing an explanation. Similarly, court cases use indirect
evidence to convict criminals for crimes lacking witnesses. C.S.I.
is one of the highest rated television shows and crime scene science is making its way into
classrooms everywhere. It's an excellent vehicle for teaching
about the nature of science. Students easily accept indirect
evidence to build a case. No one saw the crime being committed
yet evidence (data) is used to support or negate claims.
We don't have disclaimer stickers on our court cases nor should
we in science classes. A jury is not 100% sure, but they are
sure beyond a reasonable doubt. The theories now in use
are our best explanation of the data. We don't know them to be
100% correct, but they are the most probable explanation given
current knowledge and data they work beyond a reasonable
doubt. Court cases are overturned as new data or new ways to
understand the data (i.e., DNA testing) emerge. The same
is true with scientific theories. They change based on new evidence
and the power of the new theory to better explain the data. Helping
students understand how scientific knowledge develops and changes
through time will go a long way to helping them understand that
a theory in science is more than "just a theory"!
Source of checks and directions for the activity:
The November 2004 issues of Science Scope and The
Science Teacher were devoted to the nature of science. NSTA
members can access both journals on-line.