Day #4 Substances in Water Day

Agenda for the Day

Upper Anchor for Substances in Water

Learning Progression Levels for Substances in Solution

Substances in Water Activity Sequence

Student Learning and Instructional Activity Table: Substances in Water

Substances Activities

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

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

What Pathways Does Stuff in Solution and Suspension Follow?

Evaporation with a solar still

Surface Water Runoff

Celery Stalk

Soil column

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

Day #4 Substances in Water Day

Agenda for the Day

8:30Leave for Milltown Overlook

9:00Milltown Overlook

10:30Substances Upper Anchor & LP

11:00Formative Assessments for Substances

Fertilizer assessment

Construction assessment

12:00 Lunch

12:45 Substances Tools

Tracing Mixtures in Water

Scale Tool

1:15Substances Activity Sequence & Tools for Reasoning

What is in the water?

Solutions & Suspensions

Tracing Substances

Solar Stills

Celery

Soil Column

Enviroscape

3:00Break

3:15School Year Activities

4:00Wrap-up and closing

4:30Evaluations

Upper Anchor for Substances in Water

Structure & 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 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 Solution

Level 4: Model-Based Accounts

Structure & 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 Accounts

Structures & 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 Mechanisms

Structures & 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” 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 Accounts

Structures & 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 Sequence

Activity/Description / Learning Goals – Practices fused with content / Formative Assessments / Scientific Principles / Representations / Tools
Suspensions & Solutions
Students explore the difference between solutions and suspensions / -Investigate and analyze and interpret dataabout 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 dataabout 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 / Maps
Cross-Sections / -Pathways Tool
-Drivers and Constraints Tools
-Tracing Mixtures Tool

Student Learning and Instructional Activity Table: Substances in Water

What 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-L3
Microscopic to atomic-molecular L3 to L4 / Use scale tool to describe sizes of particles in suspension and molecules in solution
L2 to L3 to L4 / Use scale tool to describe sizes of particles in suspension and molecules in solution
L2 to L3 to L4 / Use scale tool to describe sizes of particles in suspension and molecules in solution
L2 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 solution
L2 to L3 to L4 / Describe/represent relative sizes of particles in suspension and molecules in solution
L2 to L3 to L4 / Describe/represent relative sizes of particles in suspension and molecules in solution
L2 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 Activities

Activity #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 Goals

In 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 Practices

  1. Investigate, analyze and interpret data about properties of mixtures and pathways of substances through systems.
  2. Engage in arguments from evidence about pathways of substances in water through systems.
  3. Use models to traces substances in water through systems
  4. Construct explanations about pathways of substances in water in a watershed.

Cross-Cutting Themes

  1. Patterns in characteristics of suspensions and solutions
  2. Differences in scale of materials in solution and suspension
  3. Pathways of other substances mixed with water through hydrologic systems
  4. Changes in distribution of both human-introduced and natural substances in environmental systems

Formative Assessments

  1. 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.

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

Summary of Activity

Students 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

Time

About 30 minutes

Question: Establish a question and elicit student ideas

  1. 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?

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 Activity

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.

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