6.11.1 Interpreting Graphs
INTERPRETING GRAPHS
In science, it is critical that students be able to interpret graphs and represent scientific
phenomena in graphic form. Although graphing skills are taught extensively in
mathematics classes, students are often unable to apply these skills to scientific concepts.
The inability of students to transfer such basic concepts should be a concern to both
science and mathematics educators. The following are some suggestions for helping
students develop important graphing and interpretation skills.
Terminology: Mathematics and science teachers often use different terms to describe
the same concepts, and this often confuses students. Make sure that your students
understand that different disciplines used different names to describe the same things.
independent variable: Mathematicians traditionally refer to horizontal axis of a
graph as the x axis or the abscissa, while scientists refer to it as the independent
variable. An independent variable is one that is unaffected by changes in the
dependent variable. For example when examining the influence of temperature
on photosynthesis, temperature is the independent variable because it does not
dependent upon photosynthetic rate. A change in the photosynthetic rate does not
effect the temperature of the air! Experimenters often manipulate independent
variables and look for changes in dependent variables in order to understand basic
relationships.
dependent variable: Mathematicians refer to the vertical axis of the graph as the y
axis or ordinate, while scientists refer to it as the dependent variable. The
dependent variable is dependent upon changes in the independent variable. For
example, photosynthesis is dependent upon temperature. A change in air
temperature will result in a change in photosynthetic production
controls: What mathematicians refer to as constants, scientists refer to as
controls. A control is a variable with only one value. For example, if scientists
are trying to understand the relationship between temperature and photosynthetic
production, it is necessary to keep other variables, such as moisture, carbon
dioxide concentration, and light constant.
It is important to provide activities that help students understand these key terms.
One such activity ("Understanding Independent, Dependent, and Control
Variables") may be found on the following page.
Conceptual Understanding: Students may be able to plot algebraic and trigonometric
functions on graph paper, yet have no conceptual understanding as to what such graphs
mean. In science, graphs are used to describe real-life relationships between independent
and dependent variables.
