Football Field Plot Study
Activity Overview and Teaching Tips
This activity takes place on the school football field (or other field) in order for students to focus on learning and understanding the field techniques. The activity starts with a guided discussion in which students develop the method they will use set up a study plot. The method is modified as purposeful questioning by the teacher reveals potential problems (abundance of plants, difficulty in counting all of them, significant overhang). Ultimately, a procedure is decided upon, students are shown how to collect coverage data, and each group conducts a study plot.
Time Required: 90 minutes
Purpose: To practice in setting up a field study plot
Research Question: Are there plant invaders on the football field? If so, what percentage of the field do they cover?
Part A: In Class
1. Decide upon plot size. Keep in mind that the plants we are studying (grasses) are very close together and plentiful. A plot size of 1 meter2 is sufficient for this activity.
2. Discuss how many plots are needed to make the study worthwhile. Is sampling one plot enough for a valid conclusion to be drawn? Help students understand that the more plots sampled, the better substantiated the conclusion will be. Have students work in pairs; assign each pair a plot.
3. Identify the native vs. alien species. Ideally a football field should be covered with grass. Bermuda grass in the dominant native grass in southern Arizona; it will be considered to be the only native plant for our study. Any other plant will be considered to be an alien (invasive, non-native) species.
4. Pick up materials. Each group will need a piece of graph paper and a meter stick.
Part B: On the Field
5. Gather students on the field. Discuss field techniques and procedures. Ask the students how we should determine the area of the plot that is covered by Bermuda grass. Sample questions are provided.
How would we determine the area covered by each plant? (Measure the diameter of the area covered by the plant and calculate the area. Assume that the coverage is circular. For a circle, the area = r2 . = 3. 14 , radius = 1/2 of the diameter)
Continue to ask students questions to help them develop the method they will use. Ask the students to consider the plants that overhang each other. Some questions you might ask include:
6. Show students how take a diameter measurement of bare places and alien plants and how to make them from two sides of the plot.
Part C: Data Analysis, In-Class
7. Determine the coverage by the Bermuda grass and the alien plants. Assume that the coverage of each plant circular. Use the equations given below.
Alien coverage = sum of area covered by
each alien plant
Native coverage = total area - alien coverage - area bare places
total area of a 1 meter plot = 100 cm x 100 cm = 1000 cm2
area of a circle = r2
area of a rectangle = length x width
area of a square = side x side
pi = 3.14
diameter = d = 1/2 x radius
Determine the area of the bare places.
Determine the coverage area of non-native plants.
Determine the coverage area of the native (Bermuda) grass.
Students should turn in a grid with the bare places and aliens
marked on it. Points will be given for the accuracy of the map, a key at the
bottom describing any markings on the map, diameter measurements to go with
map markings, and calculations for determining the percentages.