To mark where each of the before mentioned products are place a toothpick with a piece of tape labeling each product. Have students form a hypotheses over which products will remain or which products will begin to decay in a 20 day period. When 10 days have gone by, check the container by digging up the soil around the products. Cover and let set for 10 more days. Have students check their hypotheses.
Students now form a conclusion.
After checking on this day, plant grass seeds. Water the seeds until they begin to grow. Discuss that the planting of the grass over the garbage will prevent soil erosion.