Activity 9: Activity Overview
This activity provides an opportunity for the students to learn about the nitrogen
and the phosphorous cycles. The students conduct an experiment measuring the effect of lawn fertilizer and detergent on the growth of algae. In this activity, using common household chemicals, it is hoped that the students will become more cognizant of human actions as they impact not only the nitrogen and phosphorous cycles but organisms as well.
Preparation and Materials Needed
Preparation
Two weeks before the experiment, you can start reminding the students to start bringing detergent to school. Since there are usually 8 groups in a class, 4 kinds
of detergent can be used where two groups will use the same detergent. The groups can then compare results and see which detergent allows for the highest algal growth.
As to the fertilizer, get one that has the same nitrogen and phosphorous content.
This makes for fewer variables to consider.
Wide-mouth jars are easier to clean and are preferred for more efficient exchange
of oxygen with the air.
Materials/Equipment Needed (for each group)
- 3 1-L jars
- 2.25 L distilled water (750 mL per jar
- 30-mL pond water with algae (10 mL per jar)
- 45 gm lawn fertilizer (15 gm in 1 jar)
- 45 gm detergent (15 gm in 1 jar)
- plastic wrap
- glass marker
- 3 filter papers
- 3 funnels
- scale
(for each student)
- gloves
- goggles
- apron
- soap
- paper towels
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