Michael Zahm's fourth graders in Carmel, IN, gathered lots of "dirt" this year -- quite literally -- as a way of linking geography and earth science studies with indoor gardening. Letters went out early in the year to parents, teachers, and other students asking them to bring back samples of soils from their travels and vacations. By February, a remarkable 55 soil samples from 20 different states had been returned to the kids, who then plotted each sample on a map. They then examined, drew, and wrote about the soils' diverse textures, colors, components, and properties, and even created their own soil "darkness" scale, says Michael. They added water to samples of each soil, shook them, then let them sit several days until they could identify the layers of different-sized particles that settled out. Finally, the soils and the students' charts were put on display for the rest of the school.
The students next wondered whether and how soils with different qualities would affect the germination and growth of plants. They made some hypotheses, then planted beans, wildflowers, and grasses in different soil samples, and observed and gathered data as the plants grew.
"In addition to the enthusiasm and careful observations generated by this project," says Michael, "students began to realize that 'dirt' was not just 'dirt.' They noticed big differences in soils even within our own state, and found lots of evidence of living and nonliving materials. After our soil explorations, one kid returned from vacation exclaiming, 'For the first time ever, I really looked at and noticed the soil wherever I was.'"