Skill 1 of 3 · Designing and Interpreting Science ExperimentsClose
Science investigations
Design investigations, identify variables and controls, and spot flaws in an experiment.
The independent variable is what the scientist changes; the dependent variable is what changes as a result.
A control group keeps everything the same except the variable being tested.
A good hypothesis is testable: 'If I fertilize my plant, it will grow more berries' can be tested; 'if I get lucky' cannot.
Question 1 of 4
Lakes in a town are developing heavy algae growth. Scientists hypothesize that phosphorus in fertilizer used at nearby parks is causing it. They stop fertilizer use at one park and keep using it at another, then measure algae growth at both lakes for four months.
What is the independent variable in this investigation?