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The Arizona STEM Acceleration Project

Learning Through Leaf Packs!

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Lesson 1 of 8: What is a leaf pack?

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Learning Through Leaf Packs

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Experimental Design & Constructing Leaf Packs

(Lesson 1 of 8)

Middle School (6th-8th) STEM Lesson

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Susan Brown & Carrie Jenkins

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12/19/22

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Learning Through Leaf Packs

Note for Teachers: This is an 8 lesson unit that is designed to be used together to learn about the health and diversity of your local watershed by placing leaf packs into a water source (natural or man-made ponds, lakes, streams, and rivers) and attracting macroinvertebrates. Links to lessons are on the next slide.

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Why do this?!

  • Connection to science standards
  • Engage students in the scientific process
  • Authentic science
  • Citizen science (Global database)
  • Collaboration with community members
  • Students LOVE it!!!

Carrie Jenkins, 6th math & science

You don’t need a water source. This unit has a virtual option to collect data!

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Lesson Sequence

Lesson 1: What is a leaf pack?

Lesson 2: Stream Food Webs

Lesson 3: Dichotomous Keys

Lesson 4: Leaf Pack Dissection

Lesson 5: Data Analysis and the Leaf Pack Network

Lesson 6: Stream Sleuths

Lesson 7: Using Biotic Index to Infer Water Quality

Lesson 8: Chemical Water Testing to Assess Water Quality

Susan Brown, 7th science

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Notes for Teachers

  • Lesson will take one 50-60 minute class period.
  • Students will learn how scientists use leaf packs and build their own.
  • Students will design a repeatable experiment.
  • Students will explore variables in an experiment.

List of Materials

  • Dried leaves (collect and store or have students collect and bring to class)
  • Scales (metric) to measure mass of leaf pack (5 grams)
  • Leaf pack bags--mesh *make sure they are in compliance with local agencies such as the Forest Service, AZGF, etc.
  • Experiment Design Template (handout for each student)

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Arizona Science Standards

6.L2U1.13 Develop and use models to demonstrate the interdependence of organisms and their environment including biotic and abiotic factors.

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6.L2U1.14 Construct a model that shows the cycling of matter and flow of energy in ecosystems.

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Science & Engineering Practices

  • ask questions and define problems
  • develop and use models
  • plan and carry out investigations
  • analyze and interpret data
  • use mathematics and computational thinking
  • construct explanations and design solutions
  • engage in argument from evidence
  • obtain, evaluate, and communicate information

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Arizona Science Standards

Life Science Standards

Students develop an understanding of the flow of energy in a system beginning with the Sun to and among organisms. They also understand that plants and animals (including humans) have specialized internal and external structures and can respond to stimuli to increase survival.

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6.L2U3.11 Use evidence to construct an argument regarding the impact of human activities on the environment and how they positively and negatively affect the competition for energy and resources in ecosystems.

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Core Ideas

6.L2U3.12 Engage in argument from evidence to support a claim about the factors that cause species to change and how humans can impact those factors.

● Ecosystems are dynamic in nature, their characteristics can vary over time. Disruptions to any physical or biological component of an ecosystem can lead to shifts in all its populations.

● Human activities have significantly altered the biosphere, sometimes damaging or destroying natural habitats and causing the extinction of many other species.

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Objective(s):

  • Today we will learn what is a leaf pack.
  • Today we will learn how scientists use leaf packs to infer water quality.

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Agenda (1 class period)

  1. Introduce leaf packs (what are they, how do scientist use them)
  2. Benthic macroinvertebrates role in stream ecology
  3. Come up with question
  4. Set up leaf pack experiment
  5. Measure & pack leaves
  6. Make predictions

Linking Trees to Streams - Leaf Pack Network

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Intro/Driving Question/Opening

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What can we learn from leaf packs?

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What happens to leaves that fall in a pond or stream?

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They clump together

What happens after the leaves clump together?

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Attracting Pond/Stream Invertebrates

What type of invertebrates are attracted to the leaves?

What type of invertebrates are attracted to the herbivores?

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Benthic macroinvertebrates (break it down)

  • Benthic = inhabiting bottom areas or substrates
  • Freshwater = streams, rivers, lakes, ponds
  • Macro = relatively “large” (> 0.2-0.5mm)
  • Invertebrate = animals without vertebrae (a backbone)

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Benthic macroinvertebrates

  • Benthic macroinvertebrates are animals without backbones, that are visible with the naked eye, living on the bottoms of streams, river, lakes, and ponds.

Lifecycle of a caddisfly

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The Leaves

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Hands-on Activity Instructions

  • Breakout into your lab groups.
  • Measure out 5 grams of leaves into your mesh bag.
  • Make sure to zero out the scale with the mesh bag first.
  • Place in large container or garbage bag for each class period.

Optional Video: How to Make Leaf Packs

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Packing the bags - 5 grams each bag

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Do leaf types matter?

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Discuss A Testable Research Question

  • We packed half the bags with cottonwood leaves and the other half with maple leaves.
  • What is our testable research question?

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Research Question: Do Leaf Types Matter?

Distribute Controlled Experiment Worksheet (note to teacher: template link in speaker notes)

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Discuss Variables

Independent variable (what are we changing?):

    • Type of leaves (aspen or maple)

Dependent variable (what are we measuring)?

    • (type and number of macroinvertebrates)

Control variables (what are we keeping the same)?

    • (same place in the water source, amount of leaves, time in the water, etc)

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Discussion & Predictions

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  • What do you think will happen when we offer different types of leaves to the macroinvertebrates?
  • Why?
  • Will we see more macroinvertebrates in one type of leaf than another?
  • Will we see different species of macros in the aspen and cottonwood leaves?
  • Why do you think that?
  • Will there be no difference?

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Write a Hypothesis

  • If the type of macroinvertebrates found in the leaf pack (DV) is related to the type of leaves (IV),

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  • then aspen leaves/cottonwood leaves (IV) will attract different/same type of macroinvertebrates (DV prediction)

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  • because…..

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Assessment

Experiment Design:

  • Do you have a research question?
  • Do you have a hypothesis?
  • Have you accurately identified your variables?
    • Independent variable?
    • Dependent variable?
    • Controlled variables?

Exit Ticket: Why do scientists use leaf packs? Why do we have controlled variables?

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Teacher Note: Placing & Retrieving Leaf Packs

Leaf Pack Network helpful site for first timers. Check out link here.

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We have placed and retrieved leaf packs without students but you can do this with students if that works for you. We suggest using one long rope to attach leaf packs with zip ties. This ensures that all the leaf packs are kept together. Anchor the main rope to the sides of the bank. Use a sign to let anyone who passes by that this is a science experiment and do not disturb. Let leafpacks sit for 3-4 weeks. Check with local agencies for permission to place leaf packs. Use a large cooler for transporting leaf packs.

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Differentiation

Have most parts of the experiment pre-entered into experiment design template where students only have to add certain parts (research question or variables).

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Have students organized in strategic groups.

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Remediation

Extension/Enrichment

Students can engineer their own leaf pack bag for the placement of leaves.

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Students can gather & identify their own leaves for use in the experiment.

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Placing Leaf Packs (For Teacher)

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Useful Links & Resources

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Leaf Pack Network

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WikiWatershed

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Slippery Sleuths

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Using Stream Leaf Packs to Explore Community Assembly

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Macroinvertebrate ID Resources – Virginia Save Our Streams

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Nature Circles® Pond & Stream Life Card Set

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Here is an editable controlled experiment template that you can use with your students.

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Editable Controlled Experiment Template

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Susan Brown, 7th grade science teacher, NPA SBrown@northlandprep.org

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Carrie Jenkins, 6th grade science and math teacher, Sinagua Middle School CJenkins@fusd1.org

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Tara Muenz, Assistant Director of Education and Leaf Pack Administrator: tmuenz@stroudcenter.org

Students using aquatic macroinvertebrate life cycle & habitat flashcards

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  • Plastic mesh bags
  • 1 6″ sieve, 500 micron mesh
  • 1 MacroLens™,
  • 1 set of 6 Laminated, Spiral-Bound Freshwater Macroinvertebrate Dichotomous Keys
  • 1 set of 6 Biotic Index Data Sheets,
  • 30 feet of nylon twine to secure your leaf packs in the stream
  • 60 Petri dishes or similar clear dishes to place on sorting sheets
  • 12 artist’s paint brushes
  • 6 plastic sorting trays
  • 6 hand lenses
  • 12 plastic spoons
  • Dried tree leaves, 180g (30g per leaf pack)
  • 1 hand-held scale or digital kitchen scale, to weigh leaves for leaf packs
  • Dissecting microscope
  • Buckets

Stream Ecology Kit

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“Leaf Pack Stream Ecology Kit.” Stroud Water Research Center, 12 Mar. 2020, stroudcenter.org/product/leaf-pack-kit/.

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