Designing an Experiment
Variables – The conditions of an experiment that can be changed, or have a
number of different values.
Independent Variables – The conditions or factors that the experimenter
chooses for the experiment.
Dependent Variables – The factors observed to undergo a change during the
experiment.
Note: the dependent variables depend on the independent variables.
Determine the independent and dependent variables in the following
experiments:
1.
2.
3.
4.
5.
The amount of sunlight provided and plant growth
The type of mouthwash and the amount of bacteria killed
Mark received on a science test and the length of study time
The amount of heat used and the amount of time it takes to melt a
substance
Sweetness of a cup of tea and the amount of sugar added
Independent
Dependent
Controlled Experiments – in controlled experiments only one of the
independent variables is changed, and the rest are kept constant. This is done
to determine which independent variables result in the change of the dependent
variable.