Ponds are an interesting aquatic ecosystem with numerous forms of life to study.
One of the plants common to this ecosystem is a plant called duckweed. If you have a pond or stream near your home or school, collect some of these plants for the class experiment. You could also compare the plant structure of duckweed to that of the pond or stream algae. Think about the function of the various plants in the freshwater ecosystem. Many aquatic ecosystems have become endangered by human interference.