Lab: Identifying Nutrients Title
Title your lab report with a few words that
summarize the lab investigation.
Purpose
The lab report should begin with one or two
sentences that state the purpose of the
investigation—what you want to see, practice, learn
about, or test. The purpose statement answers the
question “What am I trying to find out by doing this
experiment?”
Most labs
begin as the result of a question, which is why the
introduction of your lab report should include a
question.
hypothesis should be listed
The last part of the pre-lab information section of
your lab report should be a description of the
variables. There can be up to three types of
variables, each of which is described below.
 Independent variable (IV): This is the factor that
is directly manipulated in the experiment. It is
sometimes called the manipulated variable. In the
traditional format for a hypothesis, “If X . . . then
Y,” the independent variable is X.
 Dependent variable (DV): This is the observable
factor that varies due to changes to the
independent variable. It is sometimes called the
responding variable. In the traditional format for a
hypothesis, “If X . . . then Y,” the dependent
variable is Y.
 Controlled variables: These are variables that
could affect the dependent variable, but which
you prevent from changing during the experiment.
By holding other variables constant, you can
focus an experiment on the relationship between
the independent variable and the dependent
variable