Fertilizer Frenzy

Standard II

Students will understad that the features of Earth's evolving environment affect living systems, and that life on Earth is unique in the solar system.

Objective 02

Analyze how ecosystems differ from each other due to abiotic and biotic factors.

Indicator a

Observe and list abiotic factors (e.g., temperature, water, nutrients, sunlight, pH, topography) in specific ecosystems.

Intended Learning Outcomes:

  1. Use Science Process and Thinking Skills
    1. Plan and conduct experiments in which students may:
      • Identify variables and describe the relationships between them.
      • Plan procedures to control independent variables.
      • Collect data on the dependent variable(s).
      • Analyze data, check it for accuracy and construct reasonable conclusions.
      • Prepare written and oral reports of investigations.
  2. Demonstrate Understanding of the Nature of Science
    1. Understand that science investigations use a variety of methods and do not always use the same set of procedures; understand that there is not just one "scientific method."
    2. Science findings are based upon evidence.

Summary:

Students will design and conduct an experiment testing the effect of fertilizers/soaps on algae growth.

Materials:

  • Various samples of pond water (2 liter pop bottle for each group)
  • Different types of fertilizer (each fertilizer should have different chemical ratio)
  • Different types of soaps (soaps need to contain phosphate - look for it in the ingredients)
  • Clear glass or plastic containers (200 to 500 ml. approx in size)
  • Microscopes
  • Microscope slides
  • Microscope slide cover slips
  • Eyedroppers
  • Graduated cylinders
  • Balances
  • Light source

Sequence and duration of each part of lesson:

Exploration stage

Part 1 (90 minutes)

  • Place students in groups of 4-5.
  • Give 2 liter bottle of pond water to each group, and have them observe droplets under the microscopes. (Do not tell them about experiment yet.)
  • Have students draw what they see (some previous knowledge is helpful, many living organisms will be moving rapidly).
  • Ask students:
    • What do you use at home that might contaminate the pond water?
  • After brainstorming direct students' attention to some common household contaminants (fertilizers and soaps), and ask students to predict the effect on pond water.
  • Instruct students to design and conduct an experiment to test their prediction.
  • Instruct students to keep detailed lab notes.
    • Instructions on how to keep good lab notes may be necessary.
  • Have students set up their experiments and place in the light. Make sure that they are labeled and protected from other students.

Part 2 (15-20 minutes, 3 times a week for 3 weeks)

  • Students should be allowed class time to make observations-microscopes and slides should be available.

Part 3 (3rd week)

  1. Have students take final measurements and observations.
  2. Students analyze data and write conclusions.
  3. Have students clean up their entire experiment.

Concept Invention
Part 4 (30 min)

  1. This part of the lesson should be a teacher directed discussion, where data and concepts are compared and developed.
  2. The teacher should start the discussion by asking, "What kind of relationships did you find?"
    • The teacher should make sure that all groups report, and the findings are written on the board.
  3. The teacher should then ask, "What data do you have to support your findings?"
    • The teacher should write these by the findings listed previously
  1. A follow -up question to each should be, " Does anyone have data that would support or refute these findings?
  2. The teacher could ask any of the following questions:
    1. Do your findings support your hypothesis?
    2. What do you like about each others experiments?
    3. If you were to do this again, what would you change? Why?

Application:
Part 5 (15 min)

  • Give students a scenario, and have them write a half page paper on the scenario. For Example: "What effects would a dairy farm have on a pond downstream?"

Evaluation: There are multiple ways to assess this activity. Listed below are some possibilities:

  • Have students turn in Part 5 of the lesson, for teacher evaluation.
  • Have students evaluate their team members by giving them a score on team dynamics.
  • Have students exchange lab notebooks, and evaluate their experimental set up.

Possible team dynamics rubric (out of 10 points)

     
    Proficient
    4-5 points
    Partial
    2-3 points
    Beginning
    0-1 point
    Shared the work
    		 Worked well and was willing to help on assignments Sometimes helped on the assignment Rarely helped on the assignment
    Contributed to the success of the assignment
    		 Made suggestions, helped with actual set up Helped with set up Didn't offer suggestions, didn't help with set up