Day #4 Substances in Water Day

Agenda for the Day.................................................................................................................................................... 2

Upper Anchor for Substances in Water........................................................................................................... 3

Learning Progression Levels for Substances in Solution.........................................................................4

Substances in Water Activity Sequence...........................................................................................................6

Student Learning and Instructional Activity Table: Substances in Water........................................7

Substances Activities................................................................................................................................................ 8

What’s in the Clark Fork/Santa Cruz River Water and Where Could That Stuff Go?...........10

What’s the Difference Between a Solution and a Suspension?......................................................13

What Pathways Does Stuff in Solution and Suspension Follow?..................................................18

Evaporation with a solar still...................................................................................................................21

Surface Water Runoff.................................................................................................................................. 22

Celery Stalk...................................................................................................................................................... 23

Soil column....................................................................................................................................................... 24

So What Could Be Coming Down Our River and Where Could it End Up?...............................27

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Day #4 Substances in Water Day

Agenda for the Day8:30 Leave for Milltown Overlook

9:00 Milltown Overlook

10:30 Substances Upper Anchor & LP

11:00 Formative Assessments for SubstancesFertilizer assessmentConstruction assessment

12:00 Lunch

12:45 Substances ToolsTracing Mixtures in WaterScale Tool

1:15 Substances Activity Sequence & Tools for ReasoningWhat is in the water?Solutions & SuspensionsTracing Substances

Solar StillsCelerySoil ColumnEnviroscape

3:00 Break

3:15 School Year Activities

4:00 Wrap-up and closing

4:30 Evaluations

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Upper Anchor for Substances in WaterStructure & Systems and Scale: Naturally occurring water on the Earth is a mixture of water and other substances. Two types of mixtures are solutions and suspensions. These mixtures are best described at the atomic-molecular and microscopic scales.

Solutions (Atomic-Molecular Scale): Solutions are homogeneous mixtures. As such, they have a constant composition of constituents regardless of the section or zone of the mixture observed. A solute is dissolved in another substance, the solvent. Particles are not visible in the water, although changes in color and other properties may occur. Substances that dissolve in water are composed of polar molecules that are pulled apart into their component ions or are stabilized as a whole by the electrostatic forces of the polar water molecules.

Suspensions (Microscopic Scale): Suspensions are heterogeneous mixtures that have different composition across the section of the mixture observed. Particles in suspension are visible (macroscopic to microscopic) in the water. Substances in suspension include organic and inorganic materials.

Processes & Scientific Principles: Solutions: Solutions move mix and move with water through surface, groundwater, and

biotic systems. Substances can also mix with water in the atmospheric system, but do not move from the surface to atmospheric system with water. Substances that dissolve in water are usually polar molecules. The polar nature of the water molecule pulls apart substances that have weaker ionic bonds, such as salt. How much of a substance can dissolve in water depends on the solubility of the substance in a given temperature of water and how much of the substance is already dissolved in the water (saturation). Dissolved substances separate from water when the constituent parts recombine or combine with other substances to make new substances that are not soluble in water, when water changes state and reduces the ratio solvent/solute, and when water changes temperature affecting the solubility of the solute.

Suspensions: Suspensions mix and move with water through the surface water system. How much substance moves in suspension depends on the kinetic energy of the moving water. Faster water can move more suspended material than slower water. Particles in suspension will settle out of the water due to gravity. Smaller substances will settle out more slowly than larger particles. Particles in suspension can be filtered or centrifuged from the water.

Representations: Substances in solution are represented by descriptions, drawings, or notations at the atomic-molecular scale. Molecular diagrams that show relative sizes and charges of atoms are necessary. Substances in suspension are represented at the microscopic scale with descriptions or drawings showing relative sizes of particles.

Dependency & Human Agency: The replenishing of high quality freshwater supplies depends on well-functioning natural ecosystems to filter substances in suspension and dilute substances in solution. Human actions can adversely affect the function of ecosystems or reduce the size of these ecosystems, thus reducing the capacity of these systems to provide fresh water. Human

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actions can also introduce substances that mix in both suspension and solution. While natural processes can remove these substances, their capacity to do so is limited by evaporation and infiltration rates. Concentrations of substances in water can be diluted but is limited by the volume of water available and necessary for dilution.

Learning Progression Levels for Substances in SolutionLevel 4: Model-Based AccountsStructure & Systems: Level 4 accounts identify the chemical nature of substances in water and describe changes in water quality at the atomic-molecular scale. They distinguish between substances in solution and suspension.Scale & Representations: Drawings show substances in solution and suspension at the atomic-molecular scale and often indicate awareness of the polar nature of the water molecule and its role in dissolving substances. Uses representations as models.Scientific Principles: Level 4 accounts explain why substances in solution do not move with water from the surface to atmospheric system. Dependency & Human Agency: Identifies limitations of environmental systems to provide fresh water.

Level 3: School Science AccountsStructures & Systems: Level 3 accounts relate water quality to the type of substances mixed with water. Level 3 accounts categorize types of substances that can be in water with moderate specificity, such as referring to “fertilizers” or “pesticides,” but do not identify the chemicals or elements in these substances. Level 3 accounts distinguish between biotic materials, such as bacteria, and non-biotic substances, such as silt, sand, and salt. Level 3 accounts distinguish suspensions from solutions based on whether or not substances can settle out, but often refer to anything microscopic, such as bacteria, as being in solution.Scale & Representations: Recognizes that there may be substances mixed in water may be smaller than can be visibly seen, but do not distinguish between microscopic and atomic-molecular scales. Thus, these accounts may talk about molecules or atoms but only as particles that cannot be seen.Scientific Principles: Traces substances mixed with water but does not apply model-based drivers or constraints. As a result, descriptions of pathways may be incomplete or implausible. For example, level 3 accounts may not recognize the role of water in the transportation of substances moving through underground systems or may trace water into the atmosphere with water.Dependency & Human Agency: Includes humans systems as part of the environmental systems through with substances in water move, but does not recognize in principled ways the limitations of environmental systems to provide fresh water.

Level 2: Force-Dynamic Accounts with MechanismsStructures & Systems: Level 2 accounts relate the quality of water to whether or not there is visible (e.g., trash), tasteable (e.g., salt) or generally “bad” substances (e.g., bad chemicals) in the water. Level 2 accounts provide generic labels for substances, such as “chemicals.” Changing the quality of water requires actors to remove “bad” substances or add “good”

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substances (e.g. chemicals to purify water). Level 2 drawings of suspensions and solutions do not distinguish between types of mixtures. Level 2 accounts indicate that systems are connected, but they often do not indicate that water and substances in water do not always follow the same pathways.Scale & Representations: Broad macroscopic, but does not trace substances long distances or describe molecular or atomic-molecular scale. When describing what is in the water, level 2 accounts often describe visible objects such as trash or generic substances such as “pollution.” Drawings of substances in water show macroscopic-scale representations of substances in water.Scientific Principles: Accounts use force-dynamic mechanisms to change “bad water” into “good water.” Often, someone or something is required to remove the “bad stuff” or add the “good stuff” to water to make it clean or drinkable. These accounts also frequently rely on special circumstances to explain changes in water quality.Dependency & Human Agency: Humans benefit from and are impacted by changes in water quality. Humans can also cause changes in water quality.

Level 1: Force-Dynamic AccountsStructures & Systems: Level 1 accounts of substances in water describe different qualities of water as different types of water. For example, students may describe water as dirty, clean, fresh, salty, polluted, lake, bathtub, drinking, etc. These terms all refer to different kinds of water that are separate and distinct from each other.Scale: These accounts are limited to the macroscopic and immediate scale.Scientific Principles: Level 1 accounts suggest that different types of water can be changed into other types of water by being purified or cleaned, usually by a person or a human-created agent such as a “human water cleaning system.”Representations: No connections are made between representations and the physical world.Dependency & Human Agency: Accounts state that people need clean water. Water serves to fulfill the needs of humans.

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Substances in Water Activity SequenceActivity/Description Learning Goals – Practices fused

with contentFormative Assessments

Scientific Principles Representations Tools

Suspensions & Solutions

Students explore the difference between solutions and suspensions

- Investigate and analyze and interpret data about properties of mixtures

- Engage in arguments from evidence about types of mixtures

- Fertilizer (solutions)

- Construction Site (suspensions)

- Type of mixture- Conservation of

matter

Physical models - Scale Tool

Tracing Pathways

Students explore how substances in water move through various systems

- Use models to traces substances in water through systems

- Investigate and analyze and interpret data about movements of substances in water

- Construct explanations about movements of substances in water.

- Fertilizer (solutions)

- Construction Site (suspensions)

- Water inside plant (Transpiration)

- Type of mixture- Conservation of

matter

- Physical models

- Molecular models

- Tracing Mixtures Tool

- Scale Tool

Substances in the Watershed

Students trace substances through a watershed

- Engage in arguments from evidence about pathways of substances in water in a watershed.

- Construct explanations about pathways of substances in water in a watershed.

- Fertilizer (solutions)

- Construction Site (suspensions)

- Drivers & Constraints for water

- Type of mixture

MapsCross-Sections

- Pathways Tool- Drivers and

Constraints Tools- Tracing Mixtures

Tool

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Student Learning and Instructional Activity Table: Substances in WaterWhat students need to work on (Foci for instruction)

Solutions & Suspensions

Tracing Substances through Systems

Substances in the Watershed

Structure & Systems:

Substances mix with water as either suspensions or solutions. L2 to L3

The nature of the mixture depends on the chemical properties of the substance that mixes with water. L3-L4

Investigate properties of substances L2 to L3 to L4

Investigate how and why substances in suspension and solution move through various systems L2 to L3 to L4

Explain and predict pathways of substances in suspension and solution through various systems L2 to L3 to L4

Scale

Macroscopic to microscopic L2-L3Microscopic to atomic-molecular L3 to L4

Use scale tool to describe sizes of particles in suspension and molecules in solutionL2 to L3 to L4

Use scale tool to describe sizes of particles in suspension and molecules in solutionL2 to L3 to L4

Use scale tool to describe sizes of particles in suspension and molecules in solutionL2 to L3 to L4

Scientific Principles

Substances in water do not always follow the same pathways as water. L2 to L3

The pathways substances follow depends on the nature of the mixture (suspension or solution) L3 to L4.

Explore how and why substances in suspension and solution move along with water through various systems L2 to L3 to L4

Investigate how and why substances in suspension and solution move through various systems L2 to L3 to L4

Explain and predict pathways of substances in suspension and solution through various systems L2 to L3 to L4

Representations

Representations at microscopic scale L2 to L3

Representations at atomic-molecular scale L3 to L4

Describe/represent relative sizes of particles in suspension and molecules in solutionL2 to L3 to L4

Describe/represent relative sizes of particles in suspension and molecules in solutionL2 to L3 to L4

Describe/represent relative sizes of particles in suspension and molecules in solutionL2 to L3 to L4

Dependency & Human Agency

Humans can change water quality L2 to L3

Recognizes limitations of environmental systems to provide fresh water. L3 to L4

Traces substances through connected systems L2 to L3 to L4

Explain and predict the effects of substances mixing with water L2 to L3 to L4

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Substances Activities

Summary of ActivitiesActivity #1: What’s in the Clark Fork/Santa Cruz River Water and Where Could That Stuff Go? Students indicate their ideas (through drawing and labeling) about what could be in river water and where stuff in river water could go.

Activity #2: What’s the Difference Between a Solution and a Suspension?Students compare and contrast food coloring in water, salt in water and dirt in water. They make observations about size of particles, distribution of substance in water, whether or not the mixture settles, whether or not the substance can be separated from water with a filter, and whether or not particles in the mixture scatter light. After making and recording observations, students learn the definitions of solution and suspension.

Activity #3: What Paths Does Stuff in Solution and Suspension Follow?Through using physical models that replicate what happens in environmental systems such as the Clark Fork River corridor and the Santa Cruz River corridor, students investigate how substances in solution and suspension separate or stay with water as they move through different systems.

Activity #4: So What Could Be Coming Down Our River and Where Could it End Up?Students apply their investigations in Activity 3 to consider where substances in solution and suspension might go to.

Activity #5: A Grave Mistake (Project Wet)Students analyze data to trace the flow of contaminants in groundwater and consider consequences for communities.

Learning GoalsIn these activities, students explore the following questions.

1. What’s in river water and where could that stuff go?2. What’s the difference between a solution and a suspension?3. How do substances in solution mix with, move with, and separate from water in

environmental systems?4. How do substances in suspension mix with, move with, and separate from water in

environmental systems?

Content Fused with Practices1. Investigate, analyze and interpret data about properties of mixtures and pathways of

substances through systems.

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2. Engage in arguments from evidence about pathways of substances in water through systems.

3. Use models to traces substances in water through systems4. Construct explanations about pathways of substances in water in a watershed.

Cross-Cutting Themes1. Patterns in characteristics of suspensions and solutions2. Differences in scale of materials in solution and suspension3. Pathways of other substances mixed with water through hydrologic systems4. Changes in distribution of both human-introduced and natural substances in

environmental systems

Formative Assessments1. Use the Fertilizer assessment to develop understanding of students’ ideas about what

type of mixture fertilizer forms with water and where that type of mixture can go in connected hydrologic systems.

2. Use the Construction Site assessment to develop understanding of students’ ideas about what type of mixture soil forms with water and where that type of mixture can go in connected hydrologic systems.

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What’s in the Clark Fork/Santa Cruz River Water and Where Could That Stuff Go?

Summary of ActivityStudents indicate their ideas (through drawing and labeling) about what could be in river water and where stuff in river water could go.

Materials “What’s in the Clark Fork/Santa Cruz River Water and Where Could That Stuff Go?”

handout

TimeAbout 30 minutes

Question: Establish a question and elicit student ideas1. Ask students to complete the “What’s in the Clark Fork/Santa Cruz River Water and Where

Could that Stuff Go?” sheet. This activity will give you an opportunity to elicit student ideas.2. You may want to administer this the day before you complete the other activities so that

you’ll have an opportunity to review students’ ideas about watersheds.3. Optional: Have students share out their ideas about what a watershed is. You may choose

to use a document projector so students can share their drawings and ideas about what is in the river water.

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What’s in the Clark Fork River Water and Where Could That Stuff Go?

Here is a cross-section of the Clark Fork River near Milltown. What do you think could be in the Clark Fork River water near Milltown? In the picture below, draw and label what you think could be in the water.

Choose three things you labeled in your drawing and describe where you think each thing could go next.Stuff/thing in the river water Where could it go from the river water near Milltown?

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What’s in the Santa Cruz River Water and Where Could That Stuff Go?

Here is a cross-section of the Santa Cruz River in Tucson after it rains. What do you think could be in the Santa Cruz River in Tucson In the picture below, draw and label what you think could be in the water.

Choose three things you labeled in your drawing and describe where you think each could go next.Stuff/thing in the river water Where could it go from the river water in Tucson?

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What’s the Difference Between a Solution and a Suspension?

Summary of ActivityStudents compare and contrast food coloring in water, salt in water and dirt in water. They make observations about size of particles, distribution of substance in water, whether or not the mixture settles, whether or not the substance can be separated from water with a filter, and whether or not particles in the mixture scatter light. After making and recording observations, students learn the definitions of solution and suspension.

Materials:For demo plus for each group

3 glasses or beakers 3 cups of water 1 tsp salt 1 tsp food coloring 1 tsp dirt 1 Spoon 3 pieces of filter paper or filter cones Laser pointer (use with care for eye safety and can be shared among groups) Suspensions and Solutions Chart

For each student Science notebook One observation/test table handout

Time:Two class periods

Explore Phenomena for Patterns1. Begin by providing a demonstration. Take three glasses, each with 1 cup of water. To the

first glass, add 1 teaspoon of salt. To the second glass, add 1 teaspoon of food coloring, to the third glass, add 1 teaspoon of dirt. Ask the students to observe the three mixtures, draw

a picture of each, and label characteristics of each. Make a column for each mixture on the board and ask students to share out their ideas about characteristics of each mixture.

2. Next, assign students to groups of four or five. Each group should receive materials to reproduce the mixtures described above. Let students know that they will be conducting several short experiments to more closely examine some similarities and differences between the

three mixtures. Students can either use their science notebook or the table below to record their predictions and observations. This investigation will take two days. For each mixture, students will:

a. Make observations about size of particles of substance in water (visible or not visible)

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Practices

Carry out investigations

Analyze & interpret data

b. Make observations of distribution of substance in water (evenly or unevenly distributed)

c. Predict, then test whether or not the substance settles out of the waterd. Predict, then test whether or not the substance can be separated from water with a

filter.e. Test whether or not particles in the mixture scatter light.

3. After students have completed observing, testing and recording, provide each group with a solutions and suspensions chart. Groups should use their observations and this chart to decide what type of mixture each sample is.

4. Students in their groups should also use the scale tool to identify the scale of size of the particles in the different mixtures.

5. Ask groups to share their conclusions and the evidence they used to make their conclusions. Students can agree or disagree with each other about the classifications. Facilitate the students in coming to consensus that the salt and food coloring mixtures are solutions and that the dirt mixture is a suspension.

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Practices

Construct explanations

Make arguments from evidence

Examine the three mixtures further by observing, testing, and recording what you find in this table.

Salt in water observations Food coloring in water observations

Dirt in water observations

Day OneHow large are the particles that are mixed in water (for example, are they large enough to see)?Is the substance mixed evenly or unevenly with the water? Describe.Using the laser pointer, test whether or not light is scattered (you can see the colored light beam in the water) by the mixture?Predict whether or not you think the substance will settle out of the water if it is left standing overnight. Describe why.Predict whether or not you think the substance can be filtered out of water when poured over filter paper? Describe why.Day TwoAfter standing undisturbed overnight, did the substance settle out of the water?(If the mixture settled, stir it again before doing this test). Was the substance filtered out of water when poured over filter paper?Conclusion: What type of mixture is this?

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Comparison of Solutions and SuspensionsCharacteristics Solution Suspension

Size of particles mixed with water Particles are less <1 nanometer in size (too small to be seen with eye)

Particles can be seen with naked eye (larger than 100nm)

Separation by filtration Particles will pass through a paper filter; cannot be separated except through distillation

Can easily be separated by filtering

Settles Particles do not settle when mixture is left undisturbed.

Particles settle out of water when mixture is left undisturbed.

Scatters light No (cannot see colored light beam passing through mixture)

Yes (can see colored light beam passing through mixture)

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What Pathways Does Stuff in Solution and Suspension Follow?

Summary of ActivityThrough using physical models that replicate what happens in environmental systems such as the Clark Fork River corridor and the Santa Cruz River corridor, students investigate how substances in solution and suspension separate or stay with water as they move through different systems.

Materials Substances Pathways Table for each student Materials listed for each experiment Tracing Mixtures Tools for each student

TimeAbout two class periods of time if done as a jigsaw activity (different groups do different tests). However, some of the experiments require more than one day of observations. Plan accordingly.

Establish a Question and Elicit Students’ Initial Ideas1. Tell students that they will now explore how several substances could move in water

through our river system. They will consider nitrates, which can enter the river from sources including agricultural use of fertilizers and from cattle and other animal wastes. When nitrates mix with water they dissolve and form a solution. In this activity, nitrates will be represented with green food coloring in water. They will also consider arsenic, which can enter the river from mining wastes. Arsenic can be found in river water in both dissolved form (solution) and in a form that is attached to sediments (suspension). Dissolved arsenic will be represented with red food coloring. Arsenic attached to sediment particles will be represented with red sand.

2. Ask the students to make predictions about where these substances can go from the river water on the Substances Pathways Table.

3. Next, place students in groups of about four students. Each group will test one or more of the following pathways with both a solution (food coloring in water) and a suspension (red sand mixed in water). Note that students only need to test one substance in solution --- they can then extrapolate results for how most solutions move through connected systems. The instructions for the different tests are provided in the pages below the table.

a. Can the substance move with water into the atmosphere (solar still)?

b. Can the substance move with water further down the river (enviroscape or other watershed model)?

c. Can the substance move with water through the groundwater (soil column)?d. Can the substance move with water into plants (celery stalk)?

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Practices

Carry out investigations

Analyze & interpret data

4. After students conduct their tests, create a class chart showing all of the results. Did the test results match students’ predictions? If multiple groups conducted the same tests, did they get the same results?

5. Students in their groups can next choose a substance and a place that they tested and complete a Tracing Mixtures Tool. After groups complete their tools, have them share their completed tools with the class and discuss their results and ideas about why the substance in the mixture either stayed with water or separated from water on the pathway.

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Practices

Construct explanations

Make arguments from evidence

Substances Pathways TableWill this mixture move with water into the atmosphere?

Will this mixture move with water further down the river?

Will this mixture move with water through the groundwater?

Will this mixture move with water into plants?

Prediction Observation Prediction Observation Prediction Observation Prediction Observation

Nitrates in solution

Yes / No Yes / No Yes / No Yes / No Yes / No Yes / No Yes / No Yes / No

Arsenic in solution

Yes / No Yes / No Yes / No Yes / No Yes / No Yes / No Yes / No Yes / No

Arsenic in suspension (attached to sediments)

Yes / No Yes / No Yes / No Yes / No Yes / No Yes / No Yes / No Yes / No

Choose three of your predictions above and explain why you made the prediction you did for each.1.

2.

3.

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Evaporation with a solar stillDriving Question: What happens to substances in water when the water evaporates into the air?

Materials 1 – large container 1 – small container 1 small stone – (cold – place in freezer) Plastic wrap Conductivity meter (optional) 1 Teaspoon Tape Substance mixed with water

1. Students can build their solar stills as shown above. They should place their mixture (e.g., 1 cup of water with three drops of food coloring) into the bottom of the large bowl. Next, place a smaller, empty glass cup in the center of the large bowl. Place plastic wrap over the top of the large bowl and seal. Then place a rock in the middle of the plastic wrap. The rock will direct the condensate back into the glass cup in the middle of the bow (should produce a little slope along the plastic toward the inner cup). This test takes more than one class period. Solar stills need to be placed in strong sunlight or under a strong artificial light that gives off heat to work. Distilling a sufficient sample of water may take several days so consider setting this test up earlier if you would like to conduct this lesson in just one or two class periods.

2. After the solar still has had time to work, students can carefully remove the plastic wrap and remove the inner cup from the bowl. Have students compare the mixture in the large bowl with the mixture in the cup. How did the water get into the small cup? Did the substance move with the water into the small cup. Students can make visual observations of the differences. They can also use a conductivity meter to test whether there are dissolved substances in both of the containers.

3. Students should now record their observations --- did the substance stay mixed with the water when moving into the atmosphere, or did it separate? If it separated, how/why did it separate? Could polluted water make polluted rain? Does salty water make salty rain? Why or why not? What is your evidence?

Students should find that none of the substances evaporate and condensate with the water. Water is a mixture of substances and the substances and water do not change phase at the same time or under the same conditions. Substances in suspension do not change phase and are too large to move with water molecules into the atmosphere. Substances in suspension will precipitate out of solution.******************************************************************Volatility of non-water substances

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Extension activity for advanced high school coursesSome substances will vaporize separately from water and then recombine either in the atmosphere or just return to the ground on their own. If you want to show this you can make a solar still with orange juice in it – the water in the cup should taste/smell like citrus though the color will most likely not transfer.

Surface Water Runoff

Driving Question: Which substances are transported with water in surface runoff?

Materials:Watershed model (We used this one in a paint tray liner) OR EnviroscapeSubstance being investigated (drop of food coloring or colored sand)TablespoonBucket for water disposalWatering can

1. Have each group place a tablespoon of their substance at the top of the paint tray.

2. Mist it with water using the spray bottle and record you observations in the lab sheet.

3. Pour water from a watering can over your substance and record you observations in the lab sheet. Which substances will travel with surface flow? Does the velocity of the water matter?

Students will notice that all substances mixed with water (in either suspension or solution) will runoff with water in the surface system. However, larger and heavier particles in suspension may settle out before smaller particles and substances in solution.

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Celery Stalk

Driving Question: Which substances move with water into plants?

Labeled beakers with mixtures students are investigating (one solution and one suspension)2 celery stalks with leaves

1. Add a celery stalk to each beaker.

2. Seal a plastic bag over the top of the celery stalk.

3. Place the beakers in a sunny location.

4. Over the course of a week, record observations in a science notebook.

5. Compare results among groups. Allow students to share their ideas and reasoning before providing scientific explanations.

Students will find that the substances in solution will travel up into the celery but the substances in suspension will not. None of the substances change phase with the water when it transpires.

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Soil column

Driving Question: Which substances move with water into the soil and through the groundwater?

Materials for each group:1 clear plastic water bottle1 mesh screen squares (10 cm x 10 cm)1 rubber bandScissorsConductivity meter (optional)Media (ex. sand, rocks, and/or soil)Tape & Sharpie MarkerSubstance mixed with water

1. Remove bottle cap and labels from plastic water bottles. Label the bottle with your group name and substance. Fasten the mesh screen tightly over the mouth of each bottle using a rubber band. Carefully cut the bottle in half as shown in the diagram. Turn the top half bottle upside down and place in the bottom half of the bottle. Fill the inverted bottle top half way with media.

2. Stir each mixture, and slowly pour it into the soil column. Allow all of the surface water to drain through the soil column into the bottom half of the bottle.

3. Measure the conductivity of the water in the bottom half of the bottle.

4. Record you observations. Which substances will travel with water into the ground?

Students should find that the soil filters out the substances in suspension but not the substances in solution.

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So What Could Be Coming Down Our River and Where Could it End Up?

Summary of ActivityStudents apply their investigations in Activity 3 to consider where substances in solution and suspension might go.

MaterialsApplication questions

TimeOne class period or longer if students investigate what is and/or could be done about substances in river water.

ApplicationEngage students in considering and providing explanatory accounts of the following questions. Students can work in small groups and then share ideas with the whole class.

MissoulaIn Missoula, could the following substances from each of the sources identified (arsenic in sediments, arsenic in solution, nitrates in solution)…

1. Get into our drinking water that is supplied from wells near the Clark Fork River?2. Get into the atmosphere and cause problems as air pollution?3. Runoff and end up further down the river (e.g., near Frenchtown or behind the Noxon

Rapids Dam or in the Columbia River or in the Pacific Ocean)? Could it run off and end up in the Bitterroot River or the Flathead River?

4. Get into any crops or plants that we grow near the river with river surface water irrigation?

Which possible outcomes would we need to plan for and what do you think we could/should do to protect our Clark Fork Water Resource?

TucsonIn the Santa Cruz River watershed, upstream from Tucson, are several large copper mines with tailings piles. These tailings piles are made of a slurry (wet mud) of mine waste high in arsenic and heavy metals. Where might the arsenic go?

1. Could it get into the aquifer near the tailings piles? How?2. Could it get into the air? How?3. Could it get into the Santa Cruz River water when it rains? How?

Also in this area are agricultural areas which use nitrate fertilizer. Where could the nitrates go?1. Could it get into the aquifer near the tailings piles? How?2. Could it get into the air? How?3. Could it get into the Santa Cruz River water when it rains? How?

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