This lesson is part of an Idea Set called Tracking Our Plastic: Sea to Source.

Preparation
Recommended Prior Activities:

• The Power of Plastic
• Sea to Source
• Where The Rivers Run

Materials You Provide:

• School mobile data devices, notebooks, and pencils for collecting observational data

Resources Provided:

• Handout: Water Cycle Model (linked above)
• Videos: (in carousel above)
  • Definitions in the Field: Matter
  • Sea to Source: Collecting Observational Data
• Rubric: Water Cycle Model (linked above)

Resources for Further Exploration:

• Activity: In Your Watershed

Required Technology:

• Internet access
• One computer per classroom
• Mobile data device (smartphone/tablet)
• Monitor/screen
• Projector
• Speakers

Physical Space:

• Classroom
• Parking lot
• School playground

Grouping:

• Large-group learning
• Small-group learning

Overview

Solid, liquid, and gas are states shared by many types of matter, as are the transitions between them, such as freezing and melting. Within watersheds, water transitions between these states as it moves from source to sea and back again. For example, ice melts to form rivers that flow to the ocean. Ocean water evaporates and then condenses to form clouds, from which water eventually falls as rain or freezes to become snow. It is water’s ability to transition between these phases that moves it readily around the earth’s surface!

Scientists use a variety of data collection strategies to study plastics in watersheds, and each yields different information about the environment.

• Geospatial data tracks locations—for example, the latitude and longitude of a piece of plastic pollution.
• Observational data can encompass many types of information gleaned through simple recognition (such as the number of plastic bottles at a data collection site), or measured with tools (such as the weight of plastic pollution on a scale).
• Finally, social science data focuses on people, culture, and society—for example, interviews with residents and local businesses might reveal barriers to plastic recycling.

Objectives

Students will:

• Collect observational data about local plastic debris.
• Apply states of matter and state of matter transitions to a model of the water cycle.
• Evaluate the relative merits of complementary data collection strategies.

Teaching Methods:

Demonstrations
Teaching method in which explanations are given by example or experiment.

Reflection
Student reflection includes focusing on thinking and understanding one’s own work in order to develop personal insights regarding the work or the learning process.

Experiential Learning
Learning by doing. Includes knowledge and skills acquired outside of book/lecture learning situations, such as work, play, and other life experiences. (Note: do not confuse with "learning experience.")

Skills Summary

This activity targets the following skills:

Geographic Skills

• Acquiring Geographic Information

Science and Engineering Practices

• Developing and using models
• Planning and carrying out investigations

21st Century Student Outcomes

• Learning and Innovation Skills
  • Communication and Collaboration
• Information, Media, and Technology Skills
  • Information Literacy
• Life and Career Skills
  • Flexibility and Adaptability

21st Century Themes

• Global Awareness
• Environmental Literacy

Critical Thinking Skills

• Applying
• Analyzing

Directions

1. Introduce physical elements of the water cycle and prompt students to create an initial water cycle model.

• Show the class an initial list of vocabulary describing physical elements of the water cycle. Ask volunteers for quick verbal definitions and record them in a visible location, encouraging students to also write these in their notes:
  • Glacier
  • Stream
  • River
  • Lake
  • Ocean
  • Cloud
  • Rain
• Remind students that not every watershed will have all of these elements.
  • If necessary, explore more difficult terms, such as glacier, by reading online descriptions together and asking students to draft simple, one-sentence definitions.
• Open National Geographic MapMaker and locate the Ganges (Ganga) River watershed (site of the “Sea to Source: Ganges” expedition). Project the map on a write-able surface if possible. Ask volunteers to identify, label, or draw each of the previously listed elements on the map. As students are doing so, prompt connection with prior knowledge by asking the remaining students:
  • Which of these elements can carry plastic debris? (All elements can carry plastic of one size or another!)
  • What can you hypothesize about where most plastic eventually ends up? (Plastic will likely flow with the water, eventually to the ocean.)
• Distribute copies of the Water Cycle Model handout. Ask students to draw a model of a water cycle in the space titled “Water Cycle Model Diagram” on the left, incorporating and labeling all of the physical elements defined previously in this step, and showing the movement of water with arrows. Explain that they will revise this model as they learn more about how gravity and energy move water.
  • This model should resemble a simplified version of the map of the Ganges labeled by volunteers earlier in this step. In this initial model, students may need to be challenged to consider the full meaning of the water cycle. Prompt student thinking to ensure their water does not simply flow to the ocean and stop there. The incorporation of rain and clouds should help students to discern how the water returns to its original location at the source so that the rivers can keep flowing.

2. Introduce information on states of matter to support students as they update the water cycle model.

• Inform students that they will be using a video to define three key terms relevant to water movement in watersheds: solid, liquid, and gas. Next, watch the video Definitions in the Field: Matter (0:46) as a class.
• Give students time to write definitions in their own words, and then use volunteers’ descriptions to create class consensus definitions.
• Prompt students to connect this information to the water cycle by asking:
  • When in the water cycle is water a solid? (When it is frozen, as in snow or glaciers.)
  • When in the water cycle is water a liquid? (When it can flow, as in rain, rivers, lakes, or the ocean.)
  • When in the water cycle is water a gas? (When it is in the air, as vapor.)
• Support students as they categorize all of the physical elements from Step 1 as solid, liquid, or gas.
• Assign students to label the states of matter on their Water Cycle Model handout in the “States of Matter and Transitions Diagram” section on the right, and to update their initial Water Cycle Model Diagram by labeling each physical element as solid, liquid, or gas.

3. Use a demonstration on transitions between states of matter to support students as they update the water cycle model.

• Give a live demonstration involving melting ice, evaporating water, and condensing steam. This demonstration can be simple, involving:
  • A beaker or pot of boiling water on a hot plate evaporating to create steam.
  • Ice cubes carefully lowered into the boiling water with tongs to melt.
  • A cool plate held with oven mitts above the boiling water to condense steam.
• Ask students to consider the words we use to describe water as it moves between solid, liquid, and gas states of matter.
• Request that students think quietly, pair with a neighbor, and then share with the class any of the words they may know describing how water transitions between solid, liquid, and gas states as indicated by the arrows between the boxes in the “States of Matter and Transitions Diagram.”
  • Students are likely to be familiar with the words freeze, boil, and melt. Prompt them to replace boil with the more technical term “evaporate” and to add the word “condense” to describe the transition of a gas to a liquid.
• Ask students to update the “States of Matter and Transitions Diagram” in their Water Cycle Model handout by labeling the arrows with the words for phase transitions. Finally, prompt students to add these words to any of the arrows showing water movement on the Water Cycle Model Diagram itself (for example, to label the transition from clouds to rain with the new term “condense”).

4. Practice collecting observational data associated with plastic debris with students.

• Remind students of their ultimate goal in this lesson: to answer the question: How does plastic go from me to the sea? To respond, they must continue honing their data collection skills.
• Revisit the types of observational data students gleaned from the video in the prior activity, Sea to Source. If necessary, view the video, Sea to Source: Collecting Observational Data (5:42), again as a class. (In carousel above)
• Invite students to choose an observational data collection method they would like to try (e.g., taking photographs, writing a verbal description, or conducting a measurement of the environment by eye or with an instrument).
• Ask students to use this method to observe an element of the water cycle demonstration. Gather the class around the melting ice or boiling water and prompt them to visually or verbally describe what they see.
  • Prompt students to collect observational data such that an alien who has never seen water before could understand the process occurring here. Emphasize the importance of detail and accuracy in observational data collection.
• Move the class to an outside location where they previously collected geospatial data on plastic debris. Ask each student to collect their own sample of observational data on plastic debris. Some examples include:
  • Sketching or photographing sites with plastic debris.
  • Tabulating the number and kind of plastic objects students see in a given area.
  • Collecting and measuring the weight of plastic debris (if scales are available).
• After returning to the classroom, ask students to reflect on three questions in a concluding discussion, and encourage students to record their own and peers’ responses in their notes:
  • What types of observational data collection seem particularly useful for our project challenge, and why?
  • What information can we get from detailed observational data that is different from geospatial data?
  • What particular lenses (e.g., cultural, historical, ecological) is observational data best suited to address?

Refer back to the graphic Teach About the World (in carousel above) from The Power of Plastic activity to scaffold student use of these lenses.

Informal Assessment

Student water cycle models can be evaluated using the Water Cycle Model Rubric in combination with the criteria for success listed for students on the Water Cycle Model itself.

Extending the Learning

• The activity In Your Watershed draws on similar concepts, and extends the learning regarding point and nonpoint source pollution.

Tips & Modifications

• Steps 1, 2, and 3: For support with student model creation and revision, visit Ambitious Science Teaching’s resources on small group models.
• Step 4: For additional information on using a variety of lenses to approach a single learning topic, visit Educator Tips: Teaching Across Perspectives (in carousel above).

Connections to National Standards, Principles, and Practices

Next Generation Science Standards (NGSS) available through the National Science Teacher's Association:

• Performance Expectation:
  • MS-ESS3-3. Apply scientific principles to design a method for monitoring and minimizing a human impact on the environment.
  • MS-ESS2-4: Develop a model to describe the cycling of water through Earth's systems driven by energy from the sun and the force of gravity.
• Science & Engineering Practices:
  • Planning and carrying out investigations: Plan an investigation individually and collaboratively, and in the design: identify independent and dependent variables and controls, what tools are needed to do the gathering, how measurements will be recorded, and how many data are needed to support a claim.
  • Developing and Using Models: Develop and/or use a model to predict and/or describe phenomena.
• Crosscutting Concepts:
  • Systems and System Models: Models can be used to represent systems and their interactions—such as inputs, processes and outputs—and energy and matter flows within systems.

Common Core State Standards (CCSS):

• CCSS.ELA-LITERACY.RST.6-8.4 Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a specific scientific or technical context relevant to grades 6-8 texts and topics.