Writing a Lab Report—continued
Step 2. Experimentation—continued
Experimental Controls
In every experiment,
- You must have a control
- The procedures must be repeatable.
A control is something to which the experiment can be compared. For example, if you are experimenting with flowers grown in two different fertilizers, then you must observe another group of plants grown under natural conditions (i.e. no fertilizer) as a comparison. The plants grown under natural conditions are referred to as the control. An experiment is not considered effective unless it has a valid control; other scientists must accept the control as effective for it to be considered valid.
An experiment must be repeatable. Other people must be able to verify that they can observe the same things as previous experimenters.
