The Scientific Method
A systematic approach to problem solving used by
scientists
State the problem.
Collect data through observation.
Data: recorded observations and measurements.
Observations: accurate sighting of an event.
Form a hypothesis.
A statement that explains and relates
data. A suggested solution or educated guess. A testable hypothesis is
written as an if-then statement.
Test the hypothesis through experimentation.
Experiment: a set of procedures designed
to provide data. A test of the hypothesis.
Record and analyze data.
Examine data and determine if hypothesis
is supported.
Form a conclusion.
Theory: a conclusion that has been tested repeatedly
and always shown to be true.
Law: a theory that has been tested many times
and is accepted as true.
Observations
Qualitative observations refer to descriptive,
non-numerical data, such as shape or color.
Quantitative observations refer to numerical
data, requiring measurements.
Inferences attempt to explain or interpret observations.
Experimentation
Variable:
the factor being tested in an experiment.
Independent variable: the variable being tested.
Data is plotted on the horizontal (x) axis of a graph.
Dependent variable:
any change that results from the manipulation of the independent variable.
Data is plotted on the vertical (y) axis.
Control:
a second test run in exactly the same way as the experimental test except
the variable is removed.
Constants
are the parts of an experiment that are maintained in all groups.
Experimental group:
conditions for all subjects are kept the same except for the manipulated
variable.
Control group:
conditions for all subjects are kept the same.
Experimental design
well-planned, detailed description
only one variable; others are kept constant
collect data at regular intervals
large sample size
use metrics for quantitative data
repeatable
Interpreting and Analyzing Data
Data tables organize information collected from
an experiment.
Derived data: information calculated
from collected data.
Title
Labeled columns
Include units
Graphs show relationships between the independent
variable and the dependent variable that may be difficult to see in a data
table.
-
Line graphs show the relationship between two kinds
of data in which the independent variable is continuous.
-
Bar graphs are used when there is no continuity from
piece of data to the next.
-
Pie graphs are used to show relative parts of a whole.
Interpolation is estimating between or among a series
of terms.
Extrapolation is predicting information beyond
the existing data.
Conclusion
States whether hypothesis is supported or refuted
by data.
Discussion explains why the experiment resulted
as it did.
back
to notes!