Earthworks
Earth System Science for Secondary Teachers

Zamaria Rocio (Earthworks 2002)
Zrocio@mail.sandi.net

Urban Impact on Chollas Creek (California): A Field Study

Learning Level: 6^th - 8^th grades (9^th-12^th with modifications)

California Science Content Standards addressed:

Grade 6 - Focus on Earth Sciene

Shaping Earth's Surface - 2b. Students know river and streams are dynamic systems that erode, transport sediment, change course, and flood their banks in natural and recurring patterns.

Investigation and Experimentation - 7 a-f, h. Scientific progress is made by asking meaningful questions and conducting careful investigations.

Grade 7 - Focus on Life Science

Ecology - 4 b-e. Organisms in ecosystems exchange energy and nutrients among themselves and with the environment.

Investigation and Experimentation- 7 a-e. Students develop their own questions and perform investigations.

Grade 8 - Focus on Physical Science

Motion - 1 a-f. The velocity of an object is the rate of change of its position.

Forces - 6e. Students know that when forces on an object are unbalanced the object will change its velocity.

Structure of Matter - 7f. Students know how to use the period table to identify elements in simple compounds.

Reactions - 8 a, e. Chemical reactions are processes in which atoms are rearranged into different combinations of molecules.

Physical Principals in Living Systems - 6f. Students know light can be reflected, refracted, transmitted and absorbed by matter.

Investigation and Experimentation - 7 a-g. Scientific progress.

Topic Addressed: Water Quality in Chollas Creek by looking at its macroinvertebrates.

Learning Objectives:

• See CA Science Content Standards.
• Students will learn protocols for conducting investigations: collecting data, analysis of it, forming a hypothesis, use of journal writing/field logs, GIS, water quality testing kits, identification keys for aquatic invertebrates.
• They will learn science applications and use appropriate science tools.
• They will know the macroinvertebrates which are indicators for healthy creeks, and state the factors that influence these environments.

Where: Three to four sites along creek, starting at east end (the beginning of it), 54^th street, and ending west at the San Diego Bay.

Methods:

1. Cooperative groups of four.
2. Protocol used for collection, analyzing, and graphing data.
3. Use of scientific instruments/equipment.
4. Identify macroinvertebrates using keys/field guides. Collect samples along the bottom of the creek.
5. Students will measure their research site.
6. Use of technology (GPS, computers/laptops and probes.)
7. Students will keep field notebooks (data entry, journal writing, etc.)
8. Discussion of safety, safe disposal of solutions made, and return of samples to the original locations.
9. Test physical and chemical properties of the creek at different sites.
10. Students sketch study area.
11. Data collected will be used to compare with a (relatively) pristine creek within San Diego County.
12. Students will practice reciprocal teaching mode and make up questions for self-assessment.

When: Fall 2002 (and will be an on-going study).

Resources/materials needed: GPS's, aerial photos of area (from USGS or download from internet), Hach water quality testing kits, compass, manuals/charts for aquatic animal identification (specifically macroinvertebrates), rubber boots, gloves, D-Ring, net, compound/dissection scopes, collecting trays, eye droppers, glass slides, tape, measurer, orange (fruit), forceps, thermometer, petri dishes, transportation, pH mete/paper, aquatic scientists from local universities, hand lenses, GIS software.

Potential Variables to Analyze:

1. Weather/temperature/cloud cover
2. Time of day/date
3. Description of sample site; surrounding vegetation, bank, and major landmarks.
4. Amount of shade over creek,
5. Latitude, longitude, altitude
6. Stream velocity
7. Characteristics of water sample at each site:

1. pH
2. Phosphates
3. DO
4. CO2
5. Water temperature
6. Nitrates
7. Ammonia

Extensions:

1. Research history of creek and surrounding area.
2. Have students make a simple key for macroinvertebrate identification for their peers.
3. Study other creeks feeding into the San Diego Bay.
4. For Language Arts, have students write an autobiographical or non-fiction store about their adventure in collecting these samples.
5. For Math, have students make different graphs with their data, write proportions, calculate volume and area.
6. Collected data put on school's web site.
7. Report findings (from long-term study) to the city council.