TCE     
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The Chemical Educator
ISSN: 1430-4171 (electronic version)
Abstract Volume 6
Issue 1 (2001) pp 2-4
Looking for Linearity: Integrating Graphing for First-Year Chemistry Students
Stephen DeMeo* and Pamela Mills
Department of Curriculum and Instruction and the Department of Chemistry,
Hunter College, The City University of New York, New York, NY 10021
Received August 14, 2000. Accepted October 17, 2000
Published online: 29 December 2000
Abstract. Based on our
observation that the general literature does not provide an organizing
principle for the graphs that science students encounter, an approach
called "Looking for Linearity" has been described. This approach is based
on the hypothesis that when scientists look at their data and begin to
represent it, they initially look for linearity. This is to say that scientists
use Occam’s Razor; variables are used and transformed in such ways that
when plotted against each other, the simplest representation—the straight
line—is produced. A brief review of the topics typically covered in the
first year of chemistry reveal a substantial number of relationships either
expressed in the form of a straight line (gas laws, free energy, rate
laws) or in terms of ratios that when graphed produce straight lines (density,
specific heat capacity, stoichiometry). “Looking for Linearity” is an
approach to graphing that serves four purposes for teaching first year
chemistry students: 1) it weaves a common theme or thread through the
entire year of General Chemistry, 2) it allows students to work like scientists,
3) it connects an important mathematical construct with chemical concepts,
and 4) it provides a method to process data in other scientific fields
like physics. The linearity heuristic is represented in what is called
a Graphing Decision Tree. This tree shows, in simplified terms, how linearity
can be used to organize different types of graphs found in the first year
of chemistry. The Decision Tree is hierarchically structured from simple
to increasing graphing complexity. Straight lines were listed as being
the simplest to interpret, followed by exponential curves and then non-exponential
curves; exponential curves were second because they could be converted
to straight lines by using logarithms. Each pathway ends with examples
of some of the different types of graphs our students will encounter in
the first year of chemistry.
Key Words: In the Classroom; general chemistry; graphing
(*) Corresponding author. (E-mail: svd2@columbia.edu)
Article in PDF format (157 KB) HTML format
Issue date: February 1, 2001
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