Fellow Name: Kris Kaiser

Lesson Title: What’s in the Water? Biological Water Quality

School: Culver City High School

Grade(s): 9-12

Subject(s): Biology

Kris Kaiser with student measuring pH of Ballona Creek. Photo by Janice Daniel.

Summary

The first hour is a lecture / review on what constitutes a watershed in the broad sense. Students learn about bioindicators, species which can be used to determine the health of an ecosystem. They also learn about different measurements that can indicate stream health, including dissolved oxygen, chlorine, calcium, turbidity, etc., and the significance of these. Students then internalize this when the lesson turns to specifics about their own watershed. Based on what they know going into the lesson, they are asked to predict whether their watershed will be healthy or not. We then talk about their watershed, with photos from along the watershed itself, and ask again to see if anyone changes their predictions. We then show a video of me sampling for invertebrates, bioindicators of stream health. Students make predictions about the quality of water in La Ballona creek.

On day two, we take a field trip to the creek, and students are given water testing kits to test three different parameters of water quality. Students then answer questions about their results, including the big question: was their prediction correct – is their watershed healthy or not?

On the final day, we talk about all of the results, and determine if we were correct about the health of La Ballona, and discuss how this may change over the course of the year, and why.

In what way is your lesson/activity inquiry-based?

Students make observations about images of different water sources in the introductory PowerPoint, and we will keep a list of descriptive words. Then students will make their own hypothesis and predictions about the health of La Ballona, and design their own experiment (in as much as they get to choose their own parameters to test).

Time required

One 50-min class period, plus 2 two-hour block periods.

Group size

Up to 4 students per group

Cost to Implement

LaMotte Green Water Sampling Kit - $200

http://www.lamotte.com/pages/edu/5848.html

Latex gloves for students - $100

Seine or Net for invertebrate sampling - $30

Kris Kaiser seining for invertebrates during lesson. Photo by Janice Daniel.

Learning Objectives

Explain what a watershed is.

Describe how abiotic and biotic factors affect life in urban streams.

Use macroinvertebrates as a proxy to determine watershed health.

Introduction / Motivation

Water is the basis for entire ecosystems – the oceans are an obvious one, but freshwater ecosystems are important, too. Streams are their own ecosystems, with all kinds of organisms: plants, animals, microscopic algae, not-so-microscopic algae…all these things are important in streams…but why would you care about a stream’s health?

Think about this: water is the most important thing we need to survive. We can go without food for a while, but without water even for a short period of time, we are in trouble. And – where do you think the water you drink comes from? That’s right, most likely, it comes from a stream nearby. Even bottled water has to come from a stream or pond somewhere. So – would you prefer to drink water from a clean, healthy stream, or a dirty, polluted stream?

In this lesson, we’re going to ask the question: are the streams in our area healthy?

Procedure

Before you begin: Note that the coliform bacteria test and the biological oxygen demand (BOD) in the La Motte kits require 24-48 hours to test. Because BOD requires use of the dissolved oxygen vials, I remove this option from the test kit, and allow them to test dissolved oxygen. Coliform is a popular test option. You may wish to take samples a day or two before you begin the lab so you have results for students to use for lab write-ups.

Day 1 (block)

Preassessment: Before you start, ask students to write down on a scrap sheet of paper, in their teams, their impressions about the health of the local stream or creek that you will be assessing. Have them include reasons for why they think what they do. Stress that there is no right or wrong answer; teams do not need to agree. You may want to include photos of it, so that any kids who may not know what the stream is or where it is do not feel left out. Use these later to just see if anyone changed their mind about the health of the stream based on the activity.

Use the watershed lecture. Break into teams, and let students answer question number one on the embedded assessment – here, as opposed to the preassessment, students should agree on an answer.

Return the class to the group setting, and briefly go through the watershed parameters, explaining what they mean to stream health, and what you would expect to find for healthy vs. unhealthy streams. You may want students to take brief notes here. Return students to groups and have them answer questions 2a-2c due at the end of this class period. Give them the watershed parameters handout to assist with 2c. Explain that students will be comparing all results to a control (be sure they know what a control is) and ask what they think a good control may be. Use bottled (or bottled tap or Brita filtered stream or whatever) as a control.

Day 2 (block)

Field trip! The field trip should fit in the block period if the stream is close. Students will test the three parameters they chose the previous period and record data on the attached data sheets.

This worked well for us when we divided student teams into roles:

Leader: Collects stream water, keeps team together and on task.

Time Keeper: Times experiments

Environmentalist: Collects trash, and cleans up test kits before they are returned.

Supply Clerk: requests test kits and other supplies

Reader: (optional if there is a fifth person in group) – reads instructions for test kits, and reads questions on lab report.

Give students bottled water (or bottled tap water or Brita filtered water or whatever) as a control, and make sure they understand the concept of a control, and why they might

You may want to allow teams to collect water together, some students were frustrated that only one person was allowed to the water. Students should be aware that the report is due before they leave the class, and that they should finish the report that day.

Collect and collate each period’s results. Note that the bacteria results are obvious after about 24 hours in most cases, but given too much time, they all turn yellow and it’s hard for students to see a difference.

Day 3 (50-minute period)

Go over the test results that the class got. It may be easiest to show students pictures of their tubes for coliform. If one team reverses the stream and control, thank them, and use it as a way to address experimental error, and why replication of scientific results are a good idea, because anyone can make that mistake. Talk about the results and any that are conflicting, and any misconceptions you saw on the lab reports (you don’t need to have them graded at this point, but just to have skimmed them). What is a healthy stream?

Optional focus question / question of the day/ warm up questions to accompany lesson (these allow for individuals to answer questions that groups are responsible for and allow you to catch misconceptions that may not be caught by team efforts):

Day 1: Explain 3-5 things you learned about watersheds.

Day 2: What did your tests indicate about the quality of your stream? Did you reject or accept your hypothesis?

Day 3 (after class results are presented): Do the class results indicate the same as your team’s results?

Materials List

Each group will need:

Data sheets

Assessment sheet

Field trip release forms!

Latex gloves (1 pair per person)

Stopwatch

To share with the entire class:

One water test kit

One waste bucket for used chemicals to be dumped into

Seine or net for invertebrate sampling

Boots for water sampler

Bottled (or other control) water

Safety Issues

Used tests should not be dumped back in the stream.

Stream water is likely to contain fecal coliform bacteria, indicative of other bacteria which may make students ill. Students should wear gloves, and should not eat or drink during the laboratory component. They should also wash their hands well at the end of the field trip. Some form of classroom management should be in effect so that horseplay is avoided and students are in a contained area and not pushing near the water.

Lesson Closure

Collect and collate each groups’ results in each class, and talk about what they got. Do the data meet their predictions? Was their hypothesis supported or rejected? Students do one of two lab reports, depending of level of the class: the embedded assessment leads students through each step, one by one. For a more advanced class, the lab report may be used, where students simply write the report in the introduction, methods, results, and discussion sections.

Is this lesson based upon or modified from existing materials? If yes, please specify source(s) and explain how related:

Some material in handouts comes from EPA Volunteer Stream Monitoring: A Methods Manual

List CA Science Standards addressed:

6. b. Students know how to analyze changes in an ecosystem resulting from changes in climate, human activity, introduction of nonnative species, or changes in population size.

6. d. Students know how water, carbon, and nitrogen cycle between abiotic resources and organic matter in the ecosystem and how oxygen cycles through photosynthesis and respiration. (water only covered in this lesson)