Grade Level: 7 (6-8)
Group Size: 4
Time Required: 90 minutes
Summary: During this activity, students will learn how environmental engineers monitor water quality in resource use and design. They will employ environmental indicators to assess the water quality of a nearby stream. Students will make general observations of water quality as well as count the number of macroinvertabrates. They will then use the information they collected to create a scale to rate how good or bad the water quality of the stream. Finally, the class will compare their numbers and discuss and defend their results.
Engineering Connection: Environmental engineers monitor water quality in resource use and design. They use environmental indicators to assess the water quality of streams, rivers, ponds, lakes and oceans. Building dams or factories near water affects the water quality. Environmental engineers determine the magnitude of these impacts and steps to take to mitigate them.

Learning Objectives

After this activity, students should be able to:

• Identify and measure important water quality parameters that engineers use, such as temperature and pH.
• Identify aquatic insects that can be indicators of poor water quality.
• Identify and predict cause and effect relationships in water quality.
• Create a rating tool to measure the water quality of the stream.
• Discuss and defend the results of their investigation through oral and written presentations.
• Understand why engineers are concerned about water quality and its affects on water resources.
• Explain that engineers help maintain water quality for health and recreation through monitoring and treatment.

Materials List

Each group should have:

• 1 copy of each of the three Macroinvertebrate Identification Sheets (or you may print one or two copies for groups to share)

• 1 copy of the Stream Consciousness Worksheet

• 1-liter bottle (of water sample)

• Trays or petri dishes or bowls in which student may observe samples

• 1-2 magnifying glasses or dissecting microscope (if already available)

• Thermometer

• Optional: pH paper or meter (neutral water: pH = 7)

Introduction/Motivation

Why might environmental engineers be concerned with the health of a stream? Would the stream be a possible source of drinking water for the community? Might the stream flow into a community water source? Engineers are interested in the water quality and health of a stream for conservation, restoration and resource use (fishing, recreation and drinking water).

How might an engineer be able to tell if a stream is healthy or not? How can they determine the water quality of a stream or pond? (Possible answers: looking, smelling, testing the chemistry) What are some visible indicators of stream health? (Possible answers: clear water, healthy plant growth surrounding/in the water, macroinvertebrates, presence of fish) What would good water quality look like? (Possible answers: clear or even, crystal clear) What are some indicators of bad water quality? (Possible answers: visible pollution or murkiness).

A macroinvertebrate is an organism without a backbone that can be seen with the human eye (e.g., flies, worms, larvae). Macroinvertebrates are creatures that can be sensitive to pollution. They are good indicators of water quality because they live in or near water most of their lives. They are also fairly easy to collect and observe. Engineers often use macroinvertebrates as indicators of water quality and health.

Procedure

Before the Activity

For this activity, access to a stream, creek or pond is required. There are two options of obtaining samples for this activity: as a class, walk to a stream to collect a sample or have just one adult get the stream sample in advance. (Note: A 1-liter sample of stream, creek, or pond water for each student group should be acquired). The water samples are best if a rock, covered in dirt and debris, or a slimy stick from the stream bottom is included in each.

This activity is written with the assumption that students will walk to a stream, but it can easily be used for already-prepared samples.

Print out (and consider laminating) the three Macroinvertebrate Identification Sheets – Groups 1, 2 and 3 (see Attachments) for students to share to identify their water life.

With the Students

1. Ask the students the following question: “How can we determine if a stream is healthy or not?” Tell them that this is the question they are going to answer today. There are many possible answers, and we are going to explore some methods used by engineers to help us come up with a solution.
2. Divide students into groups of 4. Each group should take a water sample (about a half liter) from the stream in a jar or tub. Try to include at least one rock covered with dirt and debris in each sample.
3. Ask students to use the thermometer to determine the temperature of the water sample and record on their Stream Consciousness Worksheet.
4. Then, they should use the pH tester or pH paper to determine the pH of the water and record on their Stream Consciousness Worksheet.
5. Have students record on the activity sheet any other observations or physical characteristics of the water (odor, color, what things are floating or sinking in your sample).
6. Next, ask students to pour a small amount of their water sample onto a petri dish or tray for observation. Using the macroinvertebrate identification chart and a dissecting microscope or magnifying glass, they should identify as many macroinvertebrates in the sample as possible. Have them list on the Stream Consciousness Worksheet which invertebrates and how many of each are found.
7. Student should then take another small amount of their sample and continue counting and identifying macroinvertebrates until they have examined the entire sample. Note: students do not need to count more than 150 invertebrates.
8. Have students count how many of each different kind of macroinvertebrate are found in their sample and write down whether they think their sample indicates good, medium or bad water quality and why.
9. Have the students create their own “rating scale” to determine the biotic index of the water. Example: for “good” invertebrates, assign a value of 10 point to each. For “bad” invertebrates, assign a value of 2 point to each. They should total the points for “good” and “bad” invertebrates and divide by the total number of invertebrates (average bug value). Have them compare this to your (teacher’s) rating scale to determine if the stream is good or bad water quality.
10. Compare your analysis with the class. Did each group come to the same conclusion? Why or why not?
11. Have each group report to the class the number of macroinvertebrates and how they rated the stream. Record the numbers on the board. As a class, calculate an average number of macroinvertebrates found and discuss any discrepancies in rating the stream. Did all the students find that it was very healthy? Or did some students rate the stream poorly while others found it was clean?
12. Ask the students to define why they rated their sample as they did.
13. Review with the students why engineers would care about water quality. Discuss how changes in water quality affect drinking water, or how water quality is used as an indicator of harmful industrial discharges or fertilizer use. Discuss how engineers may be involved in stream maintenance or restoration.

Attachments

Stream Consciousness Worksheet
Invertebrates Identification Sheet – Group 1
Invertebrates Identification Sheet – Group 2
Invertebrates Identification Sheet – Group 3

Safety Issues

Do not allow students to drink their samples.

Troubleshooting Tips

Give students a time limit for this activity or the counting portion of it; otherwise, the students will get caught up in examining the macroinvertebrates.

Assessment

Pre Activity Assessment

Brainstorming: Ask students what they think are indicators of water quality. As a class, have the students engage in open discussion. Remind students that in brainstorming, no idea or suggestion is “silly.” All ideas should be respectfully heard. Take an uncritical position, encourage wild ideas and discourage criticism of ideas. Have them raise their hands to respond. Write their ideas on the board. (Answers may include some of the following: smell, color, murkiness, number of macroinvertiberates, pH, and presence of trash.)

Hypothesize: Have students hypothesize whether or not they think the stream or sample they are going to investigate is healthy. Why or why not?

Activity Embedded Assessment

Worksheet: Have the students record their measurements and observations and follow along with the activity on the Stream Consciousness Worksheet. After students have finished their worksheet, have them compare answers with their peers.

Rate It!: Have the students create their own rating scale to determine the biotic index of the water. They should assign numbers to good and bad water quality macroinvertebrates and develop a way to quantify the health of the stream sample.

Post Activity Assessment

Take a Stand!: Have students write a persuasive essay (teacher should set length depending on time available to spend on writing). In the essay, students should pretend they are environmental engineers that were asked by the community to evaluate a stream. Their essays should clearly explain how they rated the stream and why.

Alternatively, each group of students can create a PowerPoint presentation and make a presentation to the class. In this case, the class would role play a group of experts from the community, including business leaders, citizens and other engineers.

Owner: Integrated Teaching and Learning Program, College of Engineering, University of Colorado at Boulder

Contributors: Malinda Schaefer Zarske, Janet Yowell, Melissa Straten

Copyright: 2005 by Regents of the University of Colorado
The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0226322. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.

Filed under: Grades 6-8, Lesson Plans