Carbon TIME Plants Unit- Lesson 4: Explaining How Plants Make Food, Move, and Function

Christa Haverly, Sarah Bodbyl, Christie Morrison Thomas, Kirsten Edwards, Hannah K. Miller, Charles W. (Andy) Anderson, Department of Teacher Education, Michigan State University
Type Category
Instructional Materials
Activity , Lesson/Lesson Plan
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be "fully aligned," the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.



   The Plants unit (approximately 16 hours of instructional time), part of the Carbon TIME curriculum, builds on student learning about organic and inorganic materials in the Systems and Scale unit as well as the processes learned in the Animals Unit, including how all systems exist at multiple scales and the transformation of materials and energy during chemical change. In the Plants Unit students learn how the process of photosynthesis converts light energy from the sun into chemical energy stored in glucose, how the process of cellular respiration transforms organic materials to inorganic materials and chemical energy to energy for function and movement of organisms, and how the process of biosynthesis transforms food molecules into the biomass of an organism during growth.

    This review focuses on lesson 4 (3-4 hours of instructional time) in which students use molecular models to learn how matter and energy are transformed in plants during photosynthesis and cellular respiration. The focus of this lesson is on developing explanations for how plants make food, move, and function in the light and in the dark.  This lesson helps middle school and high school students understand why plants “breathe” (i.e., exchange gasses with the air) differently in the light and in the dark and how the mass of plants can come mostly from the air. As they model photosynthesis, students learn how to explain plant gas exchange and growth in a way that follows the key rules about matter and energy—atoms last forever and energy lasts forever (in chemical changes). As students model cellular respiration, they learn how to explain this carbon-transforming process that makes food energy available to plant cells.

Intended Audience

Educational Level
  • Grade 6
  • Grade 7
  • Grade 8
  • Middle School
Access Restrictions

Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectations

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.

Clarification Statement: Emphasis is on tracing movement of matter and flow of energy.

Assessment Boundary: Assessment does not include the biochemical mechanisms of photosynthesis.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
The Carbon TIME teacher support materials provide many guidelines that need to be considered prior to beginning the sequence with a class. The set up directions and support materials are exemplary but need to be thoroughly reviewed and understood prior to facilitating student learning. Familiarity with the 5E Model (see BSCS, Bybee et al for background) is necessary. This lesson sequence is part of a longer sequence, where this portion provides that “Explanation” phase of the unit. The teacher should plan to use the entire unit to engage the students in this performance expectation. The resource gives two methods of tracking the mass of plants as they grow. The less demanding, called the 1-turtle or paper towel protocol, meets the needs of the middle school performance expectation. If a teacher feels that students need more of a challenge, there is an alternative method using gel crystals that requires more precision with measurement skills.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
Be sure to allow time for students to use the molecular models and work through the creation of the reactants and products. If students are struggling, engage them in a productive thought process by asking them what they are thinking and why. Encourage them to build a variety of combinations so they can see their ideas. The teacher needs to encourage, not show, while allowing them to develop an understanding. The creation of the molecular models will help students who need a visual to facilitate their understanding of chemical changes. Once the students have a model, be sure they understand that atoms cannot be destroyed or created, only rearranged. The videos listed are good visuals to reaffirm the understanding of the molecular model. The lessons give several opportunities to create visual and written explanations of the changes in matter and energy as photosynthesis occurs, and it is imperative that students get multiple opportunities to form and revise their explanations. Along the way, be sure to check in with individual students to formatively assess prior to moving on to the next lesson.

Disciplinary Core Ideas

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
This lesson builds on several lessons in the unit where students were investigating the mass of radish plants as they grew. In this lesson, students are considering potato plants. The accompanying slide presentations and video clips show other plants as well. The teacher may want to find and include video or text references that discuss algae and photosynthetic microorganisms to be sure that students are aware of all organisms that use photosynthesis to make sugars. The activities within this lesson (and unit) are a fantastic sequence for students to engage in and gain understanding of photosynthesis as a chemical process. The resource helps students to gather evidence of how oxygen that is released and the sugars stored in a plant are created from the matter that was carbon dioxide and water. The resource also illustrates the transfer, as well as the conservation, of energy from sunlight to chemical energy within the process.

Crosscutting Concepts

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
Throughout the four activities in Lesson 4, students are required to review what has occurred in terms of energy and matter. Although it seems repetitive, students need to be cognizant of the connection between the matter and energy in chemical reactions and the fact that the energy of the sun drives the rearrangement of atoms in the process of photosynthesis. This cross-cutting concept is fully developed in the unit if the teacher follows the plan as written. The teacher should assess individual students formatively to be sure they have an understanding of how the cycling of matter is driven by the transfer of energy. Formative strategies could be to verbally discuss, journal, or respond to a prompt on an exit ticket, depending on time available and class size.

Resource Quality

  • Alignment to the Dimensions of the NGSS: It is evident that the creators of this resource had NGSS in mind when they created the lessons. The three dimensions are intertwined throughout the process and the resource will help students to practice the skill of constructing an explanation as well as develop a conceptual understanding of “Matter and Energy” as it applies to photosynthesis and the phenomenon of plant growth. The resource aligns to the performance expectation on photosynthesis, and if used in entirety, it aligns to several others.

  • Instructional Supports: The instructional supports that are provided for the teacher as well as for the learner are exemplary. The diagrams and readings will help the teacher understand the pedagogical needs as well as the conceptual background. The materials are dense with information and will require time to review prior to engaging students. The hands-on activities and the discussions within the lessons will be a benefit to students with literacy challenges or who are English Language Learners. The resource offers two “Turtle Tracks” that offer the same content differentiated based on the ability of the students.

  • Monitoring Student Progress: The worksheets provided offer many opportunities to monitor student understanding. In addition, the slide presentations offer many moments for reflection and discussion among the class. As students work in small groups, the teacher should be sure to engage individuals in conversation to formatively assess. The developer has provided keys for all of the embedded assessments.

  • Quality of Technological Interactivity: - none -