Students are asked to determine the most appropriate site for a car wash, based on each site's soil characteristics (chemical, physical) and topographic features.

Related curriculum topics include soils, porosity, permeability, subsurface water, hydrologic cycle, natural resources (soils, water) and map reading.

Students should have some knowledge of soils, stratigraphy, porosity, permeability, the water cycle, and map reading. Students should also have experience in cooperative work and making oral presentations.

This task is designed to take students approximately 3-4 class periods (45-50 min.) to complete.

Overall Task Content Area:

Earth Science

Specific Knowledge Areas:

Structure of the Earth system;

Geochemical cycles

Performance Expectations:

• conducting investigations
• using equipment
• gathering, organizing, and representing data
• formulating conclusions from investigational data
• applying scientific principles to develop explanations and solve new problems

8 D ESS 1: Structure of the earth system: Grades 5-8
1.7 Water is a solvent. As it passes through the water cycle it dissolves minerals and gases and carries them to the oceans.

12 A SI 1: Ability necessary to do scientific inquiry: Grades 9-12
1.2 Design and conduct scientific investigations. Designing and conducting a scientific investigation requires introduction to the major concepts in the area being investigated, proper equipment, safety precautions, assistance with methodological problems, recommendations for use of technologies, clarification of ideas that guide the inquiry, and scientific knowledge obtained from sources other than the actual investigation. The investigation may also require student clarification of the question, method, controls, and variables; student organization and display of data; student revision of methods and explanations; and a public presentation of the results with a critical response from peers. Regardless of the scientific investigation performed, students must use evidence, apply logic, and construct an argument for their proposed explanations.

1.4 Formulate and revise scientific explanations and models using logic and evidence. Student inquiries should culminate in formulating an explanation or model. Models should be physical, conceptual, and mathematical. In the process of answering the questions, the students should engage in discussions and arguments that result in the revision of their explanations. These discussions should be based on scientific knowledge, the use of logic, and evidence from their investigation.

1.6 Communicate and defend a scientific argument. Students in school science programs should develop the abilities associated with accurate and effective communication. These include writing and following procedures, expressing concepts, reviewing information, summarizing data, using language appropriately, developing diagrams and charts, explaining statistical analysis, speaking clearly and logically, constructing a reasoned argument, and responding appropriately to critical comments.

12 F SPSP 4: Environmental quality: Grades 9-12
4.3 Many factors influence environmental quality. Factors that students might investigate include population growth, resource use, population distribution, overconsumption, the capacity of technology to solve problems, poverty, the role of economic, political, and religious views, and different ways human s view the earth.

National Council of Teachers of Mathematics:

DAP1: Formulate questions that can be addressed with data and collect, organize, and display relevant data to answer them:
Grades 9-12 j. understand the differences among various kinds of studies and which types of inferences can legitimately be drawn from each
Grades 9-12 k. know the characteristics of well-designed studies, including the role of randomization in surveys and experiments
Grades 9-12 l. understand the meaning of measurement data and categorical data, of univariate and bivariate data, and of the term variable
Grades 9-12 m. understand histograms, parallel box plots, and scatter plots and use them to display data

DAP3: Develop and evaluate inferences and predictions that are based on data :
Grades 9-12 h. evaluate published reports that are based on data by examining the design of the study, the appropriateness of the data analysis, and the validity of conclusions

PS3: Apply and adapt a variety of appropriate strategies to solve problems:
Grades 9-12

RP3: Develop and evaluate mathematical arguments and proofs:
Grades 9-12

CNX3: Recognize and apply mathematics in contexts outside of mathematics:
Grades 9-12

Materials for Car Wash:

At this station students should have:

3 different types of soil
stop watch
paper cups
graduated cylinder
beakers
soil testing kit (including test for pH, nitrates, phosphates, etc.)
table salt
detergents
vinegar or diluted HCl
vegetable oil
balance

Advance Preparation:

The teacher will need to have all necessary equipment available for the students. This should be sufficient for students to investigate a variety of factors concerning soil characteristics. If students requested and were given extra equipment, it should be recorded in the teacher's notes.

Normal laboratory safety procedures should be followed. Students should wear safety goggles and aprons if working with acids. Before students carry out their experiments, the teacher should review and approve them for safety.

Safety:

• Be careful.
• Teachers and students should always exercise appropriate safety precautions and utilize appropriate laboratory safety procedures and equipment when working on science performance tasks.

Administering the task
Students should be given the "Directions to Student" before beginning any work on the task. This describes the task and overall scoring procedures for each of the four scoring dimensions.

Part I is done individually. The purpose of this part is to help students access their relevant previous knowledge on this topic. Distribute Part 1: Getting Started by Yourself. Students should be given 10-15 minutes to answer the initial question.

Part II is done in groups (3 students recommended.) Distribute Part II: Group Work and the Scoring Guides for Dimension III - Collaboration and Dimension IV - Oral Communication. Students should be given 3-4 class periods to design and carry out their experiments and report the results. Cooperation should be encouraged during this phase. Students should be informed that the group will be graded as a group and this score will be shared by all members of the group using the criteria described in the Directions to the Student. Please attempt to provide students with any equipment they find relevant to their investigation. Read the Information Needed and Guidance sections which follow before administering the task. A scoring guide for Group Experimentation (Dimension II) is provided for the teacher's use. It should be completed by you and distributed to students after you have rated the group work. Each student should complete the Collaboration Scoring Guide (Dimension III) and share his/her self-ratings with the others in the group before submitting it to you.

Oral presentations of the investigation, results and conclusions, by the different groups, should be an integral part of this assessment. These presentations which take place between Parts II and III (after the groups finish writing their summary reports) give each student a chance to hear how other groups solved the problem, and give the teacher and other students an opportunity to probe the student's understanding and help them reconcile different findings and interpretations. In order to motivate all students in a group to be able to tell the whole story, the order of the presenters within a group should be designated by the teacher at the time of the presentation. Using the scoring criteria for oral presentations at the end of Part II: Group Work, the teacher should rate the oral presentations and share them with their students. In addition, students can be asked to rate their classmates using the same scoring guide created for Oral Communication.

Part III is done in class with students working individually. Distribute Part III: Finishing by Yourself. Students should be given up to 1 class period to complete these final questions. A scoring guide for Individual Understanding (Dimension 1) is provided for your use. This should be completed and distributed to students after you have rated each student's work on Parts I and III.

INFORMATION NEEDED:
Students should not be allowed to see the soil samples prior to the task. Samples should be given to students after the groups have submitted their group responses for Part II #1. Some students may have difficulty differentiating between the car wash's impact on the soil/immediate environment and its impact on the community, resulting in an overlap of responses to questions #1 and #2 in Part 1. Most groups, however, should arrive at the same combinations of responses and conclusions when they convene for group work.

GUIDANCE:
No guidance should be given to students in the design and implementation of their investigation, other than to check that students are following proper safety procedures. Students should always show their proposed plans to the teacher first, before carrying them out, due to the open-endedness of the task.

SCORING:
The teacher should score:

Dimension I Individual Understanding - based on Parts I and III
Dimension II Group Experimentation - based on Part I
Dimension IV Oral Communication - based on the oral reports in Part II

The student should rate themselves on:

Dimension III - based on Part II following the directions on the back of the rating form.
Dimension IV - If the teacher wishes, the students may also be asked to score each other during the oral reports.