Tree Leaves High and Low

Created Feb. 6, 2024 by Heidi Masters, Marcia Gardner


Timeframe: 2-3 45 min class sessions for 4th-grade students; 1.5-hour class session for elementary teacher candidates
Audience: 4th-grade students or elementary teacher candidates		Abstract: We developed an interdisciplinary lesson to help students investigate the structure and function of leaf sizes at the top and bottom of a tree.  This lesson could be used with fourth-grade students as well as elementary teacher candidates to model how to get children outdoors to learn.
Institution:
Southern Bluffs Elementary
University of Wisconsin - La Crosse		Author(s):
Marcia Gardner - mgardner@lacrossesd.org
Heidi Masters - hmasters@uwlax.edu
Current Status of Environmental Literacy and Sustainability Preparation:
Southern Bluffs Elementary School - Environmental literacy and sustainability is being infused into science, math, and literacy.

University of Wisconsin - La Crosse - All teacher candidates are required to take GEO 200: Conservation of Global Environments where they learn about natural resources, resource management, environmental and land-use ethics, environmental impacts of resource utilization, and strategies to resolve environmental conflicts. Within EDS 421: Teaching General Science Methods, teacher candidates learn about the Environmental Literacy and Sustainability Standards, the benefits of place-based education, and how to utilize the outdoor learning environment to teach all subjects.  Teacher candidates also receive training on how to use Project Learning Tree and Population Connection materials to support their instruction of environmental education.
Evidence of Need for Elementary Students:
  • When determining the area or perimeter of an object, elementary students often struggle to apply the correct formula.
  • Elementary children find it challenging to measure the area of irregularly shaped objects.
  • Students are typically unaware that objects may have the same perimeter but different areas.
  • Students think that the leaves on a tree are the same throughout.
Evidence of Need for Elementary Teacher Candidates:
  • Teacher candidates often do not consider using the outdoors as a place for learning of multiple subjects.
  • Teacher candidates often fear taking students outdoors to learn.
Evidence of Success for Elementary Students:
  • Students will correctly apply the formulas for area and perimeter to measure how the size of a leaf near the top of the tree compares to the bottom of the tree.  
  • Students will be able to determine the approximate area of a leaf from a tracing of a leaf on a grid square.
  • Students will be able to explain the reason the leaves at the top of a tree are smaller than the leaves at the bottom of a tree.
Evidence of Success for Elementary Teacher Candidates:
  • Teacher candidates will develop a plan for how to prepare children for outdoor learning.
  • Teacher candidates will reflect on how interdisciplinary lessons can be implemented in the outdoor environment.
Action Plan:
We are developing an interdisciplinary lesson that helps students investigate the structure and function of tree leaves size.  This lesson will be implemented with fourth-grade students at Southern Bluffs and used as an example within a science methods course for elementary teacher candidates.  Below we outline the lesson in detail and plan to implement it during the 2020-2021 school year.
Wisconsin Standards for Environmental Literacy and Sustainability Standards:
ELS.EX5.B.i - Describe how living things respond to changes in natural systems.

Interdisciplinary Connections:

4LS1-1: Construct an argument that plants and animals have internal and external structures that function to support survival, growth, behavior, and reproduction.

[Clarification Statement: Examples of structures could include thorns, stems, roots, colored petals, heart, stomach, lung, brain, and skin.] [Assessment Boundary: Assessment is limited to macroscopic structures within plant and animal systems.]

CCSS.MATH.CONTENT.4.MD.A.3

Apply the area and perimeter formulas for rectangles in real world and mathematical problems. For example, find the width of a rectangular room given the area of the flooring and the length, by viewing the area formula as a multiplication equation with an unknown factor .

CCSS.MATH.CONTENT.4.MD.A.1

Know relative sizes of measurement units within one system of units including km, m, cm; kg, g; lb, oz.; l, ml; hr, min, sec.

CCSS.ELA-LITERACY.RI.4.10

By the end of year, read and comprehend informational texts, including history/social studies, science, and technical texts, in the grades 4-5 text complexity band proficiently, with scaffolding as needed at the high end of the range.’

CCSS.ELA-LITERACY.W.4.8

Recall relevant information from experiences or gather relevant information from print and digital sources; take notes and categorize information, and provide a list of sources.

CCSS.ELA-LITERACY.W.4.2

Write informative/explanatory texts to examine a topic and convey ideas and information clearly.

Teacher Content knowledge:

  • Leaves towards the top of a tree have a smaller surface area because they receive more light and lose more water due to wind and heat.
  • Leaves towards the bottom of a tree have a larger surface area because they receive less light and need more surface area to conduct photosynthesis.
  • Larger and rounder leaves are the best for intercepting light. Therefore, trees/plants that prefer shade have larger leaves with less lobes.
  • Smaller leaves can handle more sunlight, as they are less likely to lose as much water and are not as affected by heat.
  • Leaves with higher length to width ratios are relatively elongate and narrow and dissipate heat faster than leaves with smaller length to width ratios.
  • Water travels better through leaves that are long and thin.
  • High winds have less impact on leaves with lobes.
  • Thin leaves (e.g., pine needles, cactus needles) do better in colder and warmer climates, as they lose less heat and water.
  • The waxy surface on the top of the leaf reduces water loss.

Materials

  • 9 leaves from the same small tree (3 from bottom, middle, and near the top of the tree)
  • Step ladder (Adults should only use this tool)
  • Ruler
  • String
  • Sharpy marker
  • Crayons/Colored Pencil
  • Paper
  • 1 cm grid paper
  • Science Notebook
  • Articles about leaf size
  • Chart paper
  • Markers
  • iPad or Science Journal

Elementary Teacher Candidate Reflection Questions before engaging in sample lesson:

  1. What are the benefits of engaging children in learning experiences outdoors?
  2. What are potential challenges of engaging children in learning experiences outdoors?  
  3. How could you address the challenges by preparing your learners in advance?

Engage:

  • Leaf hunt in the schoolyard or around home - gather 3 leaves from the bottom, middle, and as far up as you can reach with a ladder on a small-sized tree (total of 9 leaves) (For safety reasons make sure an adult is present to help gather leaves from higher up on the tree).
  • Ask students to take a picture or draw a picture of the tree and label where the leaves came from.
  • Ask the students to also label the leaves to keep track of what part of the tree they were taken from (write on the leaf with a sharpy - B = bottom, M = middle, T = top)
  • Ask students to engage in the exploration routine when examining their leaves:
  • I notice…
  • I wonder…
  • It reminds me of…
  • I think maybe…
  • Have students share their thinking with another peer before sharing out to the whole class.
  • Allow students to share their observations and thinking.  Record their ideas on a piece of chart paper.
  • GOAL: Students should notice the size of the leaves they found are different.
  • Investigable question: How do the size of the leaves near the top of the tree compare to the bottom of the tree?
  • Ask students to share some of their predictions about the reason the leaves at the top of the tree are smaller than at the bottom of the tree.

Explore:

  • Students will explore the leaves they collected further by recording down the following information:
    • Create a leaf rubbing and label visual observations of the leaf
    • Location of leaf - bottom, middle, top of tree
    • Sunlight - lots, some, little
    • Perimeter and Area of the leaf (Use yarn and a ruler to determine the perimeter of a leaf and create a leaf rubbing on 1 cm grid paper to determine the area of a leaf).
  • Have students identify which leaf represents the average for the 3 leaves at each height.  
  • The facilitator should create a whole class data chart where students can record the perimeter and area for the average leaf size from the three levels of the tree crown.
  • Students will record their data for the average leaf size at all three tree heights on the whole class data chart for comparison.
  • Students will get to compare leaf sizes from a variety of tree species to see if there is a consistent pattern between the leaf size and location on the tree.  

Explain :

  • Ask the students what they notice about the size and location of the leaf.
  • Ask the students what they think is the reason the leaf sizes vary based on location.
  • Provide students with readings to identify why the size of a leaf varies based on its location on the tree.  Have them record what they learn about leaf size and location using words and drawings from a few sources.
  • Discuss what the students learned from their readings.
  • Support the students with answering the investigable question:
    • Claim: Tree leaves near the top of the tree are smaller than at the bottom of the tree.
    • Evidence: The area of the leaves at the top of the tree were _______ and at the bottom the area of the leaves were _________.  The perimeter of the leaves at the top were _________ and at the bottom the perimeter was _________.
    • Reasoning: Tree leaves at the top of the tree are smaller, which keeps the leaves from losing as much water from the sunlight and wind.  The leaves toward the bottom of the tree are larger which helps them capture more sunlight.  

Elaborate:

  • Have students investigate a new tree to determine if the findings hold true for another tree species. (Leaves from a different climate would be interesting to explore).
  • Ask the students to explain how the size of the leaf is influenced by the location on the tree.

Evaluate:

  • Engage: Initial observations of tree leaves, predictions
  • Explore: Data collection - calculating the perimeter and area of the leaves
  • Explain: Analysis of data, ability to pull out the main ideas from the reading, and scientific explanation
  • Elaborate: Apply knowledge to a new tree

Elementary Teacher Candidate Reflection Questions after engaging in sample lesson:

  1. How do you think fourth graders would respond to this lesson?  What do you think they would do well?  What do you think they might struggle with?
  2. What subject areas did you notice were included in this lesson?
  3. What questions or wonderings do you have about teaching lessons outdoors?
  4. What are some ways that you can think of using the schoolyard or the natural environment around students' homes to teach concepts in your field experience classroom?
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