A scientist wants to perform a controlled experiment to test the effect of rust on chemically treated iron. Which action would be most important to perform in a controlled experiment?
Answer
A
Design an experiment that is based on previously published results.
B
Expose the treated iron to the corrosive effects of the air.
C
Test a large piece of treated iron and a small piece of untreated iron.
D
Test a piece of treated iron and a piece of untreated iron under the same conditions.