Second Grade gardeners took a look at dirt this week. Inside they sang Dirt Made My Lunch. Outside, in groups of ten, they began to think how exactly dirt did that fine deed. How can dirt make our lunch? Their answers: by providing us with plants and by providing the animals we eat with plants to eat.
In small groups out in the garden, second graders looked at four different kinds of dirt using their sense of touch, and an enhanced sense of sight using magnifying glasses. Here’s what they found:
Garden soil is moist and dark brown and contains: dead plants, glittering sand, clay, insects, worms, bits of bark, It holds together when you squeeze it, but breaks apart easily.
Sand is made of tiny rocks; It does not hold together well, but slides through your fingers. It does not hold water.
Clay is hard when it’s dry, and slippery when it’s wet. It holds water too well, and does not drain.
San Diego’s native soil is dry and light brown. It runs through your fingers. It has clay in it and rocks and sand. It does not hold water like garden soil, but is more like clay when it is wet.
Students also tried breaking up rocks and mixing things to make dirt. They learned it is not easy to make it. In fact, the top layer of soil on our planet takes a long time to form — up to 100 years — and is therefore a precious resource.