Run the experiment with the cardboard at a different angle, and measure the run-off. Give students seeds that can sprout relatively quickly. Maintain the seeds by watering the soil sample as needed. After a few weeks, run the experiment again, and compare the results to the first trial. After the series of trials, the class reconvenes, and shares data.
Students collaborate their results by creating a class data table or chart.
As a class, students arrange the soils from best to worst according to their performance in the various experiments. Draw a diagram of your field and the arrangement your crops. 1998 Gonick, Larry and Alice Outwater. New York. 1996. The Ecology of Commerce , Harper Business, New York. 1993.