BIOGRAPHY OF A RIVER

attempt to get maximum yield of "resource." The other team member may helpby holding the cookie still. That team member’s job is to use his/her fingers to putthe cookie back to original condition. Have teams display their success; judge howmuch resource they mined and how well they reclaimed the land.C. To demonstrate permeability of disturbed land, set the PVC pipe on its end in the shallow pan,holes nearer the bottom. Fill loosely with sand to a depth about 6-8inches above the holes. Pourenough water in the top to make a depth of about 4-6 inches. Ask students what they think willhappen. Let them observe until water comes draining out of the holes. Then pour dry Koolaid ®drink mix on top of the sand and repeat with more water, again asking students to predict what willhappen. After they have observed the colored Koolaid ® draining out of the holes, have a studentpack the sand very tightly down in the pipe, using a plastic drink bottle bottom or other tool. Askstudents what difference they think packing will make. Repeat with the water and discuss.D. (Optional): use gravel-sized crushed sandstone as a substrate to compare with thesand. Students may also want to compare the time it took for the liquid to drain withboth substrates.III. Follow-upA. Ask students what they know about the presence of iron in water, rocks, and soil. Manysoils and groundwaters have a fairly high concentration of iron, which may be seen as a rusty redor yellowish color. Ask them whether this is natural, harmful, a nuisance, etc.B. Ask students:What is formed when iron is leached out of rock by acidic water that causes therusty red color? (iron oxide or rust) What is the chemical formula for this? (Hint:The iron reacts with the oxygen in the acid.)C. Have students come up with a chemical formula for the formation of sulfuric acidfrom pyrite (FeS ) and water.2D. Have students describe and explain what happened in the PVC pipe demonstration.How does this demonstrate land disturbed by mining?IV. ExtensionHave students research the effects of high concentrations of iron on plant growth, and explainor tell what might be done to correct soils with too much iron. An experiment could be done to3-86