Beaker A-8 ml fertilizer, Beaker B-6 ml fertilizer, Beaker C-4 ml fertilizer, Beaker D-2 ml fertilizer and Beaker E-no fertilizer. Each week a random sample from each of the beakers was examined under a microscope to get a count of the number of algae cells present. What is the independent variable in this experiment? The Independent Variable in Sam’s Experiment: Fertilizer Run-Off and Algae Growth

The Independent Variable in Sam’s Experiment: Fertilizer Run-Off and Algae Growth

In order to investigate how fertilizer run-off affects the growth of algae in freshwater lakes and streams, Sam set up an experiment with five 1000 mL glass beakers containing 900 mL of water and 5 mL of water from an aquarium with a large concentration of algae. He then added varying amounts of liquid fertilizer to the beakers: Beaker A- 8 ml, Beaker B- 6 ml, Beaker C- 4 ml, Beaker D- 2 ml, and Beaker E- no fertilizer. The beakers were placed under a grow light for 12 hours each day and each week, a random sample from each beaker was examined under a microscope to get a count of the number of algae cells present. In this experiment, the independent variable is the amount of fertilizer run-off added to each beaker. This is the variable that Sam is manipulating in order to observe the effects of fertilizer run-off on the growth of algae. He is testing different amounts of fertilizer run-off in order to determine how it impacts the growth of algae in the beaker. By comparing the number of algae cells present in each beaker, Sam can determine how the amount of fertilizer run-off affects the growth of algae. Cont….