EXPERIMENT 9

WHICH SOLIDS DECOMPOSE IN SOIL

THINGS YOU NEED: Large deep tray (we’ll talk more about this later). Some soil. Test samples. The patience you used in Experiment 2.

Of all the kinds of environmental pollution we have, the most glaring kind is solid waste pollution. We see it everywhere. Not all communities have air that looks dirty or rivers that look gray. But they all have unsightly litter, garbage, and abandoned junk. (We could certainly do something about that, couldn’t we?)

The solid waste explosion in this country has reached a fantastic level of 6 billion tons a year! Of this annual total,

180 million tons (or 4 pounds per person per day) are collectd by trash trucks and hauled away for disposal. Where does this solid waste go?

One place is in sanitary landfills. Here, the waste is crushed and covered with dirt. Bacteria and moisture in the soil then set about to decompose the trash.

But, as you know, not everything decomposes (glass, for instance). And those materials that do decompose have different rates of breaking down. In this experiment, you’ll see how bacteria and moisture affect solid waste. Another thing, you’ll discover which nonmetallic materials are
biodegradable — that is, which ones can be “eaten” by bacteria. It will take a few weeks to find out these things though. Meanwhile relax. Nature’s going to do most of the
work.