I Need My Sunshine, My Only Sunshine (Using Grass)

Sarah Weber                                            RevaBeth Russell
Comstock Park High School                      Lehi High School
Comstock Park, Michigan                          Lehi, UT
weberkev@pilot.MSU.edu                         revabeth@airswitch.net
                                                              more info

Abstract: This is an inquiry lab that involves comparing and contrasting characteristics of lawn grass grown in the shade or the sun It can be a quick, low tech investigation for students to practice the process of science, or by using more sophisticated equipment, the student can go to higher levels.

Audience: grades 3-12
                    biology, ecology, math

Preparation: 10 minutes to gather materials
Running time: variable, depending how far the lab is taken
 
 

Teacher's Guide/Student Worksheet
 
 

Materials:
    lawn                                                                   More items are needed for the extension.
    metric rules                                                         That list is there.
    nail polish (clear, cheap)
    clear tape (not magic/frosted tape)
    microscopes
    microscope slides

Background and References:
 Steve Case Leaf Stomata as Bioindicators of Environmental Change
 Biology with Calculators by Scott Masterman and Scott Helmer

Background:
    The metric rulers will enable students to measure the widths of the grass blades. Depending on the amount of instruction or guidance given, the students will have to collect the data and calculate an average blade width. They will also need to make consistent measurements.
    We found, using the T-test, there was a statistical difference between the shade grass and the sun grass blade width.
 

    The students need to be able to make and count the stomata on blades of grass. If they have had practice using the nail polish and clear tape method as described in Steve Case's lesson, "Leaf Stomata as Bioindicator of Environmental Change" on Access Excellence, Go to Access Excellence. With this previous knowledge some students will see the nail polish and tape set out, and make the connection to try observing the stomata in the grass.
 

Lead in / Questions to ask students
        Have you ever noticed the lawn when you mow it or walk on it?
        Is there a difference in the grass growing in the shade and the grass growing in the sun?
        Can you set up an experiment to analyze these differences?
        Add your own.

National Standards:
 Go to National Standards
    As a result of activities 9-12, all students should develop:

        1. Abilities necessary to do scientific inquiry.

       2. Understandings about scientific inquiry.

    This activity also addresses various state content standards in life science. The objectives covered varies depending on the state curriculum.

Assessment:
    The assessment of this activity is up to the teacher. We feel there are several ways to assess this activity.  One way is to assign a lab write up, in which the students design their own presentation of data and write their own conclusions. After preparing the lab write up, students could make presentations on their experiment. Also, after completing this lab, students could create their own investigation to study their environment. See also extension activities.

Extensions:
    All information for extensions are for the teacher. The teacher can then chose to give all or none of these instructions to the students. Inquiry is possible by allowing the students, who have used the CBL probes, to go forth on their own.

Materials:
    lawn
    graphing calculators
    CO₂ sensors
    gas pressure sensors
    CBLs
    mortar pestle
    ice
    syringe in cm size
    snack size zip lock baggies

A.  Using a CO₂ gas sensor and a CBL, students can set up freshly collected sun and shade grass and compare rates of photosynthesis.
        1.  Set up CBL and graphing calculator exactly as Experiment 11 in Biology with Calculators by Scott Masterman and Scott Holman (p. 77).  Go to Lab 11
        2.  Tape 15 to 20 blades of sun grown grass together so that no blades are covered.  Push grass into the collecting jar and collect data with graphing calculator and CBL.
        3. Repeat steps one and two with shade grown grass.
        4.  Compare graphs of the sun and shade grown grass.

C.  A low tech way for the students to see enzyme activity in shade and sun grown grass. (Plants are alive too.)
        1.  Put 20 ml of H₂O₂ in a snack size zipper lock bag. Make sure all the air is out and the baggie is sealed tight.
        2.  Push this down into a 1000 ml graduated cylinder that has 500 ml of water in it. Observe the displacement.

        3.  Quickly add 4 drops of "grass juice" that was extracted as in Extension 2b into the baggie.
        4.  Quickly and completely seal the baggie and push back into the water in the graduated cylinder.
        5.  Observe for several minutes, watching the water displacement.
        6.  Compare with grass from another location.

D.  Math Applications:
        1.  Counting of stomata viewed through microscope view finder several times and figuring out the average number of stomata.
        2.  Statistics can be taught using Microsoft Excel and data collected by measuring the grass.

I Need My Sunshine, My Only Sunshine (Using Grass)

Objective: To develop an experiment analyzing grass growing in the shade and grass growing in the sun.

Procedure:
1.  With your partner, formulate a hypothesis that you can test.
2.  Using the equipment that your teacher has provided test your hypothesis.
3.  Show your hypothesis to your teacher before you go outside to collect your data.
4.  Collect and record your data. Does it support your hypothesis?
5.  Write up your conclusions.