Steward-shed Investigation



Class Periods




Subject Areas

Science, Social Studies


Students conduct research on point and nonpoint sources of pollution in their steward-shed.


  • Identify point sources of pollution in their steward-shed.

  • Identify nonpoint sources of pollution in their steward-shed.

Before you get started


  • Explore ToxTown, a rich source of information on environmental health hazards from the National Institute of Health.  Decide in advance whether you want to select relevant passages for your students -- based on your knowledge of your steward-shed -- or whether your students will explore ToxTown on their own.  If they explore on their own, they could become anxious about the ubiquitous sources of toxins in their environment.  Plan ahead how you want to help them manage that anxiety.

  • Explore at least the city- and federal-level resources described in “Our Steward-shed” Library of Resources under “Maps to Study Pollution”.  Based on the information available for your steward-shed, decide which resources you will encourage your students to explore.  To help you quickly find the most relevant features of these map, you can consult BOP’s guides, located inside “Our Steward-shed Library”:

    • “Guide to Using the OASIS Map”

    • “Guide to Using the Envirofacts Map”

  • Optional: explore the state-level resources as well.  For most neighborhoods, we think those will be most useful for in-depth research, and not necessarily for your students’ first pass at this kind of research.

  • Prepare a zoomed-in satellite image of your class’ steward-shed, with the boundaries drawn on it, from the lesson Steward-shed Investigation Part 1 - Paper watersheds


  • Good introduction to pollution in estuaries from NOAA.  It’s worth clicking through the tabs on “toxic substances”, “nutrient pollution”, “pathogens”, and “invasive species” -- to help you wrap your mind around the different kinds of pollution that end up in our estuary.

  • Another important way of categorizing pollution is point-source vs. nonpoint-source.  It’s usually easier to spot point-source pollution:  someone is dumping or leaking something from a specific location.  Nonpoint-source pollution is a very big problem, and it’s happening in your steward-shed, so it’s worth teaching your students to recognize a few of the most common examples of nonpoint-source pollution:

Instruction Plan


  1. Students re-examine their Class steward-shed map  (details in “Preparation” section, above).

  2. Students brainstorm what they know or wonder about that area, in an open-ended way.

  3. Ask your students, “based on your personal memories of this place, what kinds of pollution do you think are happening in our steward-shed?”

  4. Post their responses for the whole class to see under the label “Based on Personal Memory” -- so that later they can compare what they remembered with what they learned from maps, and what they learned from direct observation.


  1. Students access the resources you have selected from “Our Steward-shed” Library of Resources and possibly ToxTown.  (You should choose these in advance based on your steward-shed and your students -- see “Preparation” for details).

  2. Students or groups have Class steward-shed map, and explore the resources you have selected to annotate the map -- ideally with access to post-its and colored pencils or markers -- to show the sources of pollution they find in the map resources.


  1. Students or groups share out some of the pollution sources they have found.

    • Post their findings for the class to see under the label, “Based on Maps”.

    • As questions come up, post them, to see if students will be able to answer some of them throughout their research in this Steward-shed Investigation.

  2. Most students will probably identify point sources of pollution.  If some students also mention non-point sources of pollution, that is a great moment to introduce the vocabulary!

    • If students only mention point sources of pollution, ask them, “How about cars?  They are a big source of pollution.  Where are there a lot of cars in our steward-shed?  Can you tell that on the maps?  How so?”

    • And then, “what about litter?  What are all the different times that there might be littering going on in our steward-shed?  Is there anything on the maps to tell us where litter could be happening in our steward-shed?”


  1. Students go back into the resources, in search of specific point sources or nonpoint sources that they had not noticed before.  (They could choose between point and nonpoint, or you could divide up the two tasks, or you could assign everyone to look for both.)

  2. Students add this new information to their annotated maps.

  3. Students share out the new things they have noticed, while you continue to post their findings and questions.


  1. Ask your students, “Which seems to be a bigger problem in our steward-shed, point-source pollution or nonpoint-source pollution?

    • Of course there is no wrong answer to this question, but students can make strong or weak arguments for their positions.

  2. Ask your students, “Of the sources of pollution you found in the maps today, which do you think are visible to a pedestrian observer?  Which might be hidden from the public view?  Why might that be?”  

    • This is to prepare students for the field observation in the following lesson.


NGSS - Cross-Cutting Concepts

  • Cause and Effect

    • Cause and effect relationships may be used to predict phenomena in natural or designed systems.
    • Cause and effect relationships may be used to predict phenomena in natural systems.
  • Influence of Engineering, Technology, and Science on Society and the Natural World

    • All human activity draws on natural resources and has both short and long-term consequences, positive as well as negative, for the health of people and the natural environment.
    • The uses of technologies and any limitation on their use are driven by individual or societal needs, desires, and values; by the findings of scientific research; and by differences in such factors as climate, natural resources, and economic conditions. Thus technology use varies from region to region and over time.
  • Scale, Proportion, and Quantity

    • Time, space, and energy phenomena can be observed at various scales using models to study systems that are too large or too small.
  • Science Addresses Questions About the Natural and Material World

    • Scientific knowledge can describe the consequences of actions but does not necessarily prescribe the decisions that society takes
  • Structure and Function

    • Complex and microscopic structures and systems can be visualized, modeled, and used to describe how their function depends on the relationships among its parts, therefore complex natural structures/systems can be analyzed to determine how they function.
    • Structures can be designed to serve particular functions by taking into account properties of different materials, and how materials can be shaped and used.
    • Structures can be designed to serve particular functions.
  • Systems and System Models

    • Models can be used to represent systems and their interactions.
    • Models can be used to represent systems and their interactions—such as inputs, processes and outputs—and energy and matter flows within systems.
    • Systems may interact with other systems; they may have sub-systems and be a part of larger complex systems.

NGSS - Disciplinary Core Ideas

  • ESS2.C: The Roles of Water in Earth's Surface Processes

    • Water continually cycles among land, ocean, and atmosphere via transpiration, evaporation, condensation and crystallization, and precipitation, as well as downhill flows on land.
    • Water’s movements—both on the land and underground—cause weathering and erosion, which change the land’s surface features and create underground formations.
  • ESS3.C: Human Impacts on Earth Systems

    • Human activities have significantly altered the biosphere, sometimes damaging or destroying natural habitats and causing the extinction of other species. But changes to Earth’s environments can have different impacts (negative and positive) for different living things.
  • ETS1.A: Defining and Delimiting Engineering Problems

    • The more precisely a design task’s criteria and constraints can be defined, the more likely it is that the designed solution will be successful. Specification of constraints includes consideration of scientific principles and other relevant knowledge that are likely to limit possible solutions.
  • ETS1.B: Developing Possible Solutions

    • A solution needs to be tested, and then modified on the basis of the test results, in order to improve it.
  • ETS1.C: Optimizing the Design Solution

    • Although one design may not perform the best across all tests, identifying the characteristics of the design that performed the best in each test can provide useful information for the redesign process - that is, some of the characteristics may be incorporated into the new design. (secondary)
    • Although one design may not perform the best across all tests, identifying the characteristics of the design that performed the best in each test can provide useful information for the redesign process—that is, some of those characteristics may be incorporated into the new design.
  • LS2.A: Interdependent Relationships in Ecosystems

    • Organisms, and populations of organisms, are dependent on their environmental interactions both with other living things and with nonliving factors.

NGSS - Science and Engineering Practices

  • Asking Questions and Defining Problems

    • Ask questions that can be investigated within the scope of the classroom, outdoor environment, and museums and other public facilities with available resources and, when appropriate, frame a hypothesis based on observations and scientific principles.
    • Define a design problem that can be solved through the development of an object, tool, process or system and includes multiple criteria and constraints, including scientific knowledge that may limit possible solutions.
  • Constructing Explanations and Designing Solutions

    • Undertake a design project, engaging in the design cycle, to construct and/or implement a solution that meets specific design criteria and constraints.
  • Developing and Using Models

    • Develop a model to describe unobservable mechanisms
    • Develop a model to generate data to test ideas about designed systems, including those representing inputs and outputs.
    • Develop a model to predict and/or describe phenomena
  • Obtaining, Evaluating, and Communicating Information

    • Gather, read, and synthesize information from multiple appropriate sources and assess the credibility, accuracy, and possible bias of each publication and methods used, and describe how they are supported or not supported by evidence.

NYC Science Scope & Sequence - Units

  • Grade 6, Unit 2

    • Weather and Atmosphere
  • Grade 6, Unit 4

    • Interdependence
  • Grade 7, Unit 1

    • Geology
  • Grade 8, Unit 4

    • Humans and the Environment: Needs and Tradeoffs