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Plants Unit

Carbon TIME: Plants Unit

Systems and Scale is the first of the six Carbon TIME units. If you are new to teaching Carbon TIME, read the Carbon TIME FAQ: Which Units Should I Teach.

Lead Editor for 2019 Version

Kirsten D. Edwards, Department of Teacher Education, Michigan State University

Principal Authors

Kirsten D. Edwards, Department of Teacher Education, Michigan State University

Christie Morrison Thomas, Department of Teacher Education, Michigan State University

Elizabeth Tompkins, Michigan State University

Hannah K. Miller, Northern Vermont University

Christa Haverly, Department of Teacher Education, Michigan State University

Charles W. “Andy” Anderson, Department of Teacher Education, Michigan State University

Contributing Authors

Beth Covitt, Jenny Dauer, Jennifer H. Doherty, Allison Freed, Wendy Johnson, Deborah Jordan, Craig Kohn, Lindsey Mohan, Joyce Parker, Emily Scott, Carly Seeterlin, Alex Walus, Nicholas Verbanic, Pingping Zhao


Craig Douglas, Kendra Mojica

This research is supported in part by grants from the National Science Foundation: A Learning Progression-based System for Promoting Understanding of Carbon-transforming Processes (DRL 1020187) and Sustaining Responsive and Rigorous Teaching Based on Carbon TIME (NSF 1440988). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation or the United States Department of Energy.

This unit is also available online at Contact the MSU Environmental Literacy Program for more information:

The Driving Question

The Plants Unit starts by asking students to express their ideas about the driving question about an anchoring phenomenon: How does a radish plant grow, move, and function?

Carbon is the key! In the unit, students learn to tell the story of how matter and energy are transformed as they move through plant systems. A particularly powerful strategy for explaining how plant systems transform matter and energy involves tracing carbon atoms. For more information about the Next Generation Science Standards disciplinary core ideas included in this unit see the sections on the Matter Movement, Matter Change, and Energy Change Questions below and the Unit Goals.

Research base. This unit is based on learning progression research that describes the resources that students bring to learning about plants and the barriers to understanding that they must overcome. It is organized around an instructional model that engages students in three-dimensional practices.

Before beginning the Plants Unit, you need to decide what to teach and importantly, what not to teach! Use this page to choose the unit sequence that’s most appropriate for your students.

  • Some activities are REPEATING ACTIVITIES (). Omit these activities if students have already completed them in another unit (unless you’d like students to repeat them as review).
  • Other activities are TWO-TURTLE ACTIVITIES (), which place a higher demand on students. Decide whether the higher demand required by these activities will be useful or distracting for your students. The Carbon TIME Turtle Trails Document document provides further info about choices for making units more or less demanding, depending on your students’ needs.

Unless otherwise noted in the table below, all activities in the unit should be taught.

Here, we present two ways to think about how lessons are sequenced in the Plants Unit. The Instructional Model, immediately below, emphasizes how students take on roles of questioner, investigator, and explainer to learn and apply scientific models they can use to answer the driving question. Further below, the Unit Storyline Chart highlights the central question, activity, and answer that students engage with in each lesson of the Plants Unit.

Instructional Model

Like all Carbon TIME units, this unit follows an instructional model (IM) designed to support teaching that helps students achieve mastery at answering the driving question through use of disciplinary content, science practices, and crosscutting concepts. To learn more about this design, see the instructional model.

The core of the Carbon TIME IM is the Observation, Patterns, Models (OPM) triangle, which summarizes key aspects to be attended to as the class engages in unit inquiry and explanation. The OPM triangle for the Plants Unit, shown below, articulates the key observations students make during the unit investigation, the key patterns they identify through analyzing their investigation data, and the central scientific model that can be used to answer the unit’s driving question. During the inquiry portion of the unit (Lesson 3), the class moves from making observations to identifying patterns, eventually using these patterns to make evidence-based arguments. During the explanation portion of the unit (Lessons 4, 5, and 6), the class learns the atomic-molecular model, makes connections across scales, and uses the atomic-molecular model to explain how animals grow, move, and function. Across the unit, classroom discourse is a necessary part of 3-dimensional Carbon TIME learning.

The Carbon TIME Discourse Routine document provides guidance for scaffolding this discourse in lessons.

plants unit map

The tables below show goals for this unit in two forms. A list of Next Generation Science Standards (NGSS) addressed by this unit is followed by a table showing specific target performances for each activity.

Next Generation Science Standards

The Next Generation Science Standards (NGSS) performance expectations that middle and high school students can achieve through completing the Plants Unit are listed below. To read a discussion of how the Carbon TIME project is designed to help students achieve the performances represented in the NGSS, please see Three-dimensional Learning in Carbon TIME.

High School

  • Chemical Reactions. HS-PS1-4. Develop a model to illustrate that the release or absorption of energy from a chemical reaction system depends upon the changes in total bond energy.

  • Chemical Reactions. HS-PS1-7. Use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction.

  • Structure and Function. HS-LS1-2. Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms.

  • Matter and Energy in Organisms and Ecosystems. HS-LS1-5. Use a model to illustrate how photosynthesis transforms light energy into stored chemical energy.

  • Matter and Energy in Organisms and Ecosystems. HS-LS1-6. Construct and revise an explanation based on evidence for how carbon, hydrogen, and oxygen from sugar molecules may combine with other elements to form amino acids and/or other large carbon-based molecules.

  • Matter and Energy in Organisms and Ecosystems. HS-LS1-7. Use a model to illustrate that cellular respiration is a chemical process whereby the bonds of food molecules and oxygen molecules are broken and the bonds in new compounds are formed resulting in a net transfer of energy.

  • Matter and Energy in Organisms and Ecosystems. 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.

Middle School

  • Structure and Properties of Matter. MS-PS1-1. Develop models to describe the atomic composition of simple molecules and extended structures.

  • Chemical Reactions. MS-PS1-2. Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.

  • Chemical Reactions. MS-PS1-5. Develop and use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved.

  • Matter and Energy in Organisms and Ecosystems. 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.

  • Structure, Function, and Information Processing. MS-LS1-3. Use argument supported by evidence for how the body is a system of interacting subsystems composed of groups of cells.

  • Matter and Energy in Organism and Ecosystems. 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.

  • Matter and Energy in Organism and Ecosystems. MS-LS2-3. Develop a model to describe the cycling of matter and flow of energy among living and non-living parts of an ecosystem.

Materials You Provide

Pre-Activity 0.2GL: Keeping Track of Solids in Mixtures

Pre-Activity 0.2GL: Plant Growth Investigation Setup

Pre-Activity 0.2PT: Plant Growth Investigation Setup

Activity 1.1: Plants Unit Pretest

Activity 1.2: Expressing Ideas and Questions about How Plants Grow

Activity 2.1: Zooming into Plants, Animals, and Decomposers

Activity 2.2: Molecules Cells Are Made of

Activity 2.3: Molecules in Cells Quiz

Activity 2.4: Questions about Plants

Activity 3.1: Predictions and Planning about Radish Plants Growing

Activity 3.2 (PT or GL): Observing Plants’ Mass Changes, Part 1

Activity 3.3: Observing Plants in the Light and Dark

Activity 3.4 (PT or GL): Observing Plants’ Mass Changes, Part 2

Activity 3.5: Evidence-Based Arguments about Plants

Activity 4.1: Molecular Models for Potatoes Moving and Functioning: Cellular Respiration

Activity 4.2: Explaining How Plants Move and Function: Cellular Respiration

Activity 4.3: Molecular Models for Potatoes Making Food: Photosynthesis

Activity 4.4: Explaining How Plants Make Food: Photosynthesis

Activity 5.1: Tracing the Process of Potatoes Growing: Biosynthesis

Optional Activity 5.2: Molecular Models for Potatoes Growing: Biosynthesis

Activity 5.3: Explaining How Potato Plants Grow: Biosynthesis

Activity 6.1: Explaining Other Examples of Plants Growing, Moving, and Functioning

Activity 6.2: Functions of All Plants

Activity 6.3: Comparing Plants and Animals

Activity 6.4: Plants Unit Posttest