First, you should start by asking students questions about how to set up the experiment. Suggested questions include:
Where should we locate our experimental lines?
The experiment should be located in an area where the transect lines will not be disturbed by students or others. It also should be located in as flat an area as possible to minimize water runoff into other transect lines.
Do you want any distance between controlled and watered lines?
If the transect lines are physically side-by-side, water from the experimental lines could easily run into your control lines. If your grassy area is hilly, water may run from the watered plots into the control plots. In either case, the additional water in the control plots would bias your data; this is also true for the question above.
What is the purpose of the control/non-watered lines? Why are they so important?
Control transect lines are for comparison. Controls serve as the “normal” condition against which you measure the experimental condition. In this case, the control grassy lines will grow as they “normally” would without any additional water. The experimental grassy lines will receive more water than normal. Your students will measure any changes between quantities of reproductive structures (fruits and seeds) in the control vs. quantities in the experimental lines.
Next, determine the experimental layout and how to run the experiment (see Figure 1).
One potential experimental layout:
Variation on a theme: If no grassy area exists at your school or you cannot get permission to use your school grounds to run this project, you could run the experiment in pots outdoors or in a greenhouse. This potentially could be done in several ways.
Now that you have completed your experiment, reread the short EurekAlert article and pp. 26-27 in the Cherry & Braasch book.
How was your experiment similar to or different from those performed at the Angelo Reserve?
The Angelo Reserve research involved plots and the collection of multiple functional groups of plants. Your research involved transect lines and only two functional groups of plants (grasses and non-grasses). Whole plants were harvested at the Angelo Reserve, which causes more destruction to the experimental area but your students were harvesting the reproductive parts (fruits and seeds) only to minimize disturbance to the school yard. Fewer functional groups will minimize confusion when processing your plant parts. There is more emphasis on reproductive output in your students’ experiment.
How was your experiment similar to or different from those performed in the Tundra (pp. 26-27 in Cherry & Braasch book)?
Again, both your students and the tundra research were done to simulate what might happen as a result of global climate change. The tundra experiments focus more on varying temperature as the experimental variable, where your students focused on differences in amounts of water.
Did the amounts (mass) of fruits and seeds (reproduction) differ between your control and experimental plants due to increased water?
You should see greater fruit and seed production on the experimental transect lines versus the amount collected from the control transects.
Do you think increasing or decreasing rainfall in your school yard would change plant reproduction?
You should see greater overall fruit and seed production with increases in water and the opposite with decreases in water. The interesting comparison, however, is the relative amounts you find between the experimental and control transects. Your students should see the connection between more water and more fruits and seed production (reproductive output).
Do you think increasing or decreasing rainfall could also affect the animals that live in your school yard (remember reading about the grasshoppers and spiders in the Angelo Reserve, and caribou in the tundra)?
Hopefully your students will understand the connection between plant production and animal production from the reading. If the amount and kinds of plants change, the amount and kinds of animals which feed on the plants will probably also change too. If you have the opportunity to count plant feeding insects along your transect lines, this might help them see the connection.
Do you think increasing or decreasing rainfall might affect the crops and horticultural plants grown in your town or state?
This is an extension of the previous question. If the connection between wild plants and animals exists, this connection must also exist between humans (we are also animals) and the plants we feed on and grow. This is the connection between global climate change and us.