Stream Creatures: Clues to Stream Health – Session 3
Conduct this session in the schoolyard.
- Tell students that in this session the class will be acting out three plays: one for each of three streams being monitored. In each play 20 students will be needed to play the roles of the stream macroinvertebrates. If you have more than 20 students, the extras may play the parts of water or other stream inhabitants; if fewer, some students may take on two roles.
- Provide each student with a Schoolyard Stream Simulation Data Sheet PDF • Word and a piece of graph paper. In addition, students should bring their Macroinvertebrate Fact Sheet PDF • Word. (If available, give each student a clipboard to hold each of the items.)
- Hand outSchoolyard Stream Simulation Cards PDF • Word for Stream 1. Instruct the students that as actors they must consult their fact sheets to study the character indicated on their simulation card. The fact sheet will provide students with clues for imitating their character. For example, the actor portraying a crayfish might use his or her hands as claws and make shredding motions; the leech might make sucking noises; the mayfly might pretend to crawl out of his or her skin; the aquatic worm might wiggle.
- Direct the actors to start uphill, if possible, and to move downhill, as if they were flowing, until they reach you, who, playing the scientist, will collect them in your net.
- Once you catch the macroinvertebrates, direct all the tolerant ones to get into a group. Count these, and instruct students to record the number on Data Sheets.
- Next tell students to group themselves according to the type of organism they portray. As a class, count and record the number of different organisms on the Simulation Data Sheet. This number will indicate the level of diversity in the stream ecosystem.
- Repeat steps 2–6 for the Stream 2 and Stream 3 Simulation Cards.
- Find a shady spot or return to the classroom, and have students fill in the rest of the data sheet, discussing how the fraction of tolerant organisms is determined and how that is converted to the percent tolerant.
- Instruct students to draw two graphs on their graph paper: one showing the percentage of tolerant macroinvertebrates in each stream, and the other showing the biodiversity in each stream. Use the graphs to compare the streams. (See Preparing Graphs and Charts in the Project Action Guide.) Discuss what the graphs communicate about the health of each stream. Speculate about what could be happening on the land of each stream's watershed to affect the water quality.