This math and science activity about photosynthesis and calculating the biomass of trees includes a video and a linked worksheet for students to complete a similar investigation on their own.
The video leads students through a fast-paced investigation to determine the mass of a tree, where the mass comes from, and how much carbon dioxide a tree has absorbed in its lifetime.
Students will learn what percentage of a tree is made up of carbon, how a tree’s biomass can be estimated using only the diameter of the tree’s trunk, and how to calculate the amount of carbon dioxide a tree has absorbed.
Teaching Tips
Positives
The linked activity contains a written recap of the concepts covered in the video and is located in the description of the video.
The linked activity provides students with a chance to practice estimating the amount of carbon dioxide sequestered in a tree in their own community.
Additional Prerequisites
Students should be familiar with basic chemistry to understand the discussion of the mass ratio of carbon dioxide to carbon.
Students will need to understand the relationship between the circumference and the diameter of a circle.
The video provides a short description of both photosynthesis and allometry, but students unfamiliar with the topics will need more background knowledge to fully understand the concepts.
Differentiation
Connections can be made with math classes that are learning about geometry, graphing, or data collection and analysis.
Biology classes can use this video and activity to hook students before a lesson about photosynthesis or as a lab exercise after learning about the carbon cycle.
After estimating the amount of carbon dioxide sequestered in a tree, students can use a carbon footprint calculator to estimate their own carbon footprint and then determine how many trees it would take to cancel it out.
Advanced students can research why different tree species have different biomass estimations, even when their diameters are the same.
Scientist Notes
This resource uses allometry to calculate the biomass of a tree. From there, it demonstrates how to estimate the amount of carbon dioxide sequestered in a tree. This resource is recommended for teaching.
Standards
Next Generation Science Standards (NGSS)
ESS2: Earth's Systems
HS-ESS2-6 Develop a quantitative model to describe the cycling of carbon among the hydrosphere, atmosphere, geosphere, and biosphere.
LS1: From Molecules to Organisms: Structures and Processes
MS-LS1-6 Construct a scientific explanation based on evidence for the role of photosynthesis in the cycling of matter and flow of energy into and out of organisms.
MS-LS1-7 Develop a model to describe how food is rearranged through chemical reactions forming new molecules that support growth and/or release energy as this matter moves through an organism.
HS-LS1-5 Use a model to illustrate how photosynthesis transforms light energy into stored chemical energy.
LS2: Ecosystems: Interactions, Energy, and Dynamics
HS-LS2-4 Use mathematical representations to support claims for the cycling of matter and flow of energy among organisms in an ecosystem.
HS-LS2-5 Develop a model to illustrate the role of photosynthesis and cellular respiration in the cycling of carbon among the biosphere, atmosphere, hydrosphere, and geosphere.
College, Career, and Civic Life (C3) Standards
Dimension 1: Developing Questions and Planning Inquiries
D1.4.9-12 Explain how supporting questions contribute to an inquiry and how, through engaging source work, new compelling and supporting questions emerge.
CCSS.MATH.CONTENT.HSG.GMD.A.1 Give an informal argument for the formulas for the circumference of a circle, area of a circle, volume of a cylinder, pyramid, and cone. Use dissection arguments, Cavalieri's principle, and informal limit arguments.
Geometry: Modeling with Geometry (9-12)
CCSS.MATH.CONTENT.HSG.MG.A.1 Use geometric shapes, their measures, and their properties to describe objects (e.g., modeling a tree trunk or a human torso as a cylinder).