Students can observe the activity and growth of living things in two aquariums. The one aquarium should be filled with rainwater and one with polluted water. The polluted water can be obtained from a lake or stream. Fish should not be included in an aquarium that has been made polluted by adding laundry soap or oil. Plant growth can be observed in this situation. The students should notice that the plants are more attractive and the fish are active in the tank that is filled with rainwater.
Use two identical flowerpots, each filled ½ full with quality potting soil. Add trash to one pot. Add mulch and leaves to the other. Fill the remainder of each flowerpot with potting soil. Transfer healthy flowering plants to each flowerpot. The plants in the healthy soil will have space for their roots to develop. These plants should recover from the transplanting quickly and grow well. The plants in the trash-filled flowerpot will wilt and die because they have insufficient space.
Smog can be imitated in a glass canning jar by putting a teaspoon of vinegar into the quart jar, then adding a lighted match and sealing the jar quickly with a piece of aluminum foil. Invert this smog-containing jar over an identical jar that contains some sprouted grass seeds. Students should observe that the growth of the grass seeds decreases after the exposure to the smog.
Observe worms in a composting bin that has been properly managed with the regular addition of decomposable hay, straw, sawdust, leaves, grass clippings and vegetables. Compare this to a compost bin that has had poor management and the addition of nondecomposable items such as plastic. Fill one planter with each type of compost. Plant 10 green bean seeds into each planter. Students observe the growth of the beans in each planter. They should notice that more beans spout in the good compost compared to the poorly managed compost.