# Middle School Stream Investigation: observing stream erosion, calculating stream discharge, and determining stream chemistry and turbidity

#### Summary

In this field investigation, students will observe erosional patterns in a small stream, calculate discharge at four points along the stream, draw four depth profiles for the points where they determined discharge, and collect data on stream chemistry and turbidity. In small groups students will use this data to give a class presentation showing the information they collected and what new testable questions they were able to develop. After all of the class presentations, the class will work to draw conclusions in a large group discussion and determine what new testable questions can be used the next year.

## Learning Goals

## Context for Use

I designed this activity to be used at the end of the school year for a multitude of reasons. The students will have a background into the rock cycle, basic chemistry, taking metric measurements, and recording information in their science journals. This investigation is designed to be a culmination of all of the different concepts and skills the students have gained throughout the school year. I also hope to follow up this investigation with an exploration the following year regarding stream ecology and how that relates to erosional patterns in the stream.

The anticipated time frame for this investigation, including pre- and post-work, is approximately seven class periods. The first fifty-minute class period will be an introduction, which will include what questions students have and what knowledge they have about local streams. This class period will also include information on how to go about collecting data and what equipment they will be using. Equipment will include meter sticks, ropes, matches or ping pong balls, stop watches, and a La Motte water quality test kit. This kit has simple tests for determining pH, nitrates, phosphates, dissolved oxygen, alkalinity, turbidity, and temperature. I'm anticipating that the field investigation will take 2-3 hours; this will be considered one class period. The next two fifty-minute class periods will be time for students to compile data and develop a presentation for class. The fifth and sixth class periods will be devoted to presentations and the last class period will be a time for drawing conclusions and looking at the new testable questions the small groups developed.

**Subject**: Geoscience:Hydrology:Surface Water

**Resource Type**: Activities:Field Activity:Field laboratories

**Special Interest**: Field-Based Teaching and Learning

**Grade Level**: Middle (6-8)

## Description and Teaching Materials

The first fifty minute class period will be conducted in the classroom. This lesson will start in small groups of about 3 to 4 students. These groups will have about 10 minutes to brainstorm and come up with about five things they know about streams or have observed in the past. The small groups will then share their observations and knowledge. (The main reason for asking what students know is to eliminate any misconceptions they may have.) I then want to focus the discussion on erosional factors and erosional patterns by asking students what they think influences stream erosion. After discussing these I will introduce the term discharge. Discharge is the amount of water that flows past a particular point in a certain amount of time. I will then explain how you determine discharge using a mathematical formula Discharge = Width * Depth * Velocity. I will then ask the students how they would measure these factors using a meter stick, rope, matches, and a stop watch to calculate the discharge. At this time I will guide students in the planning of their procedure for taking these measurements.

Students are required to take notes calculating discharge and set up a data table for collecting discharge information in there science journals. They will be informed that they must take these measurements at four places along the stream and also make four depth profiles of the stream.

The next part of the first fifty-minute lesson will be devoted to stream chemistry and turbidity. Students will be given approximately ten minutes to come up with five questions or things they know about stream chemistry in their small groups. After ten minutes they will be asked to share what they determined or questions they have from their small group discussion. I will then discuss the different testing kits they will have to conduct a stream chemistry analysis. After discussing and showing the different kits, the students will be asked what they think these different tests can tell them about the stream. I will review what these different tests can tell us about the stream. Students will then be required to make a data table in their science journals for collecting their chemical analysis data.

NOTE: Both the discharge and chemical analysis data tables must be checked off with the teacher before the field investigation. This will limit frustrations and potential problems with data collection in the field.

The last part of the class period will be devoted to the details of the investigation. Each group must conduct discharge measurements at four different places along the stream as well as make four depth profiles. Students must then measure pH, nitrates, phosphates, dissolved oxygen, alkalinity, turbidity, and temperature at one location along the stream using the La Motte stream testing kit. Groups will have to share testing kit supplies. Safety information and additional directions will be given at this time.

The second class period will be a 2-3 hour field investigation at Farmer's Park in Stockton, MN. Students will be asked to collect data discharge and chemical analysis data, make and document observations, and develop questions using Garvin Brook. Special emphasis will be placed on taking thorough notes.

The third and fourth class periods will be devoted to creating presentations in their small groups. Students will spend the next two class periods creating a presentation to summarize their data, make connections, and develop a new testable question based on their findings. The students will have the opportunity to work with the teacher on their presentations and use PowerPoint to summarize data for their presentations.

The fifth and sixth class periods will be devoted to giving presentations. Students will be assessed on presentations using a rubric format. Each group will be required to develop at least one question they have regarding the other groups' presentations. These may pertain to things that were unclear or questions regarding the investigation.

The seventh class period will be a class discussion pertaining to the testable questions that the small groups developed for their presentations. This class period will also be used to discuss possible misconceptions and to determine what possible testable questions can be carried out the following year or for eighth grade year long science projects.

Materials

La Motte Stream monitoring kit

12 meter sticks

12 stop watches

12 ten meter lengths of rope

Students must have science journals, pencils, calculators

## Teaching Notes and Tips

Students will have data tables created ahead of time for field work and will have their procedure outlined in their science journals. I will split the groups up and ask some to conduct discharge calculations and some to conduct chemical and turbidity tests due to limits on available testing materials.

In the past students used stream tables to look at how sediment patterns change based on slope, type and amount of sediment, and discharge.

## Assessment

## Standards

8.I.B.3 Scientific Inquiry

8.3.A.2 Earth Structure and Processes