Designing an experiment: An experiment is an organized procedure to study something under controlled conditions.

Does fertilizer in lake water make algae grow? 1. Determine a purpose Does fertilizer in lake water make algae grow?

2. Write a hypothesis Use the form, “If… then… because….” If the amount of fertilizer in lake water increases, then the amount of algae will also increase, because fertilizers provide nutrients that algae need to grow.

3. List materials

4. Determine Variables and Constants A Variable- any factor that can change

Independent variable- is the factor that you wish to test. If ______________ If the amount of fertilizer in lake water increases

Dependent variable- is the factor that you measure to gather results. Then__________ then the amount of algae will also increase

Constants – all of the factors that are the same in each test group.

Control group- standard for comparison, same as the experimental group except for the factor that you wish to test.

5. Write a procedure 6. Record Observations- usually in a table or chart

7. Summarize results- often done by making a graph 8. Draw conclusions- paragraph to explain the experiment