Final answer:
In the "IQ Water" experimental design, students are referred to as 'subjects' as they are the ones being experimented on and observed.
Step-by-step explanation:
In the experimental design example "IQ Water," students fulfill the role of subjects. They are the individuals being observed or experimented on in the study. In experimental design, the term 'variable' refers to any component that can change within the study. A 'control' is either a part of the study that remains constant or a group that does not receive the experimental treatment, which is essential in comparing outcomes. 'Constants' are specific conditions that are kept unchanged throughout the experiment to ensure that the results are due to the variable being tested.