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

Illustrations

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 http://carbontime.bscs.org/. Contact the MSU Environmental Literacy Program for more information: EnvLit@msu.edu.

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.

Students’ Roles and Science Practices

As students learn to answer the driving question by explaining how animal systems transform matter and energy, they play three different roles that encompass all of the Next Generation Science Standards science and engineering practices. (For more details on science and engineering practices, see the Unit Goals.)

Questioners: Students explore the driving question, clarify, and generate more detailed questions
Investigators: Students conduct matter-tracing investigations of radish plants growing; and develop evidence-based arguments about key observations and patterns
Explainers: Students construct model-based explanations of how a potato plant grows and functions.

The roles that students play are embedded in the Carbon TIME instructional model and Discourse Routine. The Discourse Routine guides how classroom discourse aimed first at divergent thinking and then at convergent thinking should be sequenced through the unit.

Good Explanations Answer the Three Questions

Students figure out how to answer the driving question by tracing carbon-containing molecules through a series of movements and chemical changes inside plants. At each stage in these processes they answer Three Questions about what is happening: the Matter Movement Question, the Matter Change Question, and the Energy Change Question. Below, we use the anchoring phenomenon of plant growth as an example of how students learn to answer the Three Questions for different plants

Note that, in Carbon TIME, NGSS crosscutting concepts serve as the “rules of grammar” for producing a scientific performance. With respect to plants growing, high quality explanations should attend to the following rules that are implied by crosscutting concepts. Explanations should attend to…

Scale by explaining events and phenomena at the appropriate scale (see more in the structure and function bullets below).
Systems and system models and energy and matter by following rules for tracing matter and energy through systems and system models. For example, neither energy nor matter should be created or destroyed as it moves into, through, or out of a system.
Structure and function by linking structures and functions in explanations at each scale.
- Macroscopic scale (tracing matter and energy through processes occurring in plants and plants systems)
- Cellular scale (tracing matter and energy into and out of cells as cellular functions are carried out)
- Atomic-molecular scale (tracing matter and energy through chemical processes—cellular respiration and biosynthesis—involving molecules with different structures and properties)

The Matter Movement Question: Tracing Molecules Through Plants

Students learn to tell the following story of how carbon-containing molecules move through plants.

Carbon atoms enter plants in CO₂ molecules that are absorbed through the leaves, where they become part of glucose (sugar) molecules.
The sugar molecules travel through the stems and roots to all of the plant’s cells.¹
Some of the carbon atoms stay in the cells, as they are incorporated into the large organic molecules that make up cell structures through biosynthesis.
Some of the sugar molecules are oxidized in the process of cellular respiration. They leave the plant in CO₂ that diffuses through plant surfaces.

¹ Sugar molecules travel through the phloem as the disaccharide sucrose (C₁₂H₂₂O₁₁) rather than the monosaccharide glucose (C₆H₁₂O₆). We do not feel that this distinction is important for basic life science courses.

The Matter Change and Energy Change Questions: Explaining How Plants Use Organic Molecules to Grow, Move, and Function

Matter movement is an essential part of the story, but not the whole story. To answer the driving question, students learn to explain chemical changes that occur inside plants:

Photosynthesis. Plants’ leaf cells absorb CO2 and water. They use energy from sunlight to rearrange the atoms into new molecules: glucose and oxygen. Glucose has chemical energy stored in their C-C and C-H bonds.
Biosynthesis and growth. Plants grow when their cells grow and divide through the process of biosynthesis. Plant cells combine glucose with soil minerals to make other small organic molecules. Then they combine small organic molecules to make the large organic molecules needed for cells’ structure and function.
Cellular respiration—energy to move and function. Plant cells get the energy they need to move and function by combining sugars and other small organic molecules with oxygen, releasing energy when high-energy C-C and C-H bonds are replaced by lower-energy bonds in carbon dioxide and water.

How Much Detail?

There are more complicated and more scientifically accurate ways of talking about chemical bonds and about changes in energy; we discuss some of those in detail in our educator resource: Carbon TIME Carbon TIME Content Simplifications. But our learning progression research has shown that there is an important tradeoff here—many students get lost in the details and never learn a basic coherent story that answers the driving question. The Next Generation Science Standards take a clear position on this tradeoff; a coherent story based on principles such as matter and energy conservation is more important than the details. Consult the Unit Sequence tab and the sections on Extending the Learning at the end of each Activity page to decide how much detail is appropriate for your students.

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.

Unit Storyline Chart

Another way to familiarize yourself with the sequence of lessons in the Plants Unit is with the Unit Storyline Chart depicted below. The Unit Storyline Chart summarizes a unit phenomenon-based driving question associated with each lesson, what classes will do in each lesson to address the question, what conclusions they will come to, and how they will transition to a subsequent lesson.

Download Unit Storyline Chart

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.

http://www.nextgenscience.org/hsps-cr-chemical-reactions

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

http://www.nextgenscience.org/hsps-cr-chemical-reactions

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.

http://www.nextgenscience.org/hsls-sfip-structure-function-information-processing

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

http://www.nextgenscience.org/hsls-meoe-matter-energy-organisms-ecosystems

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.

http://www.nextgenscience.org/hsls-meoe-matter-energy-organisms-ecosystems

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.

http://www.nextgenscience.org/hsls-meoe-matter-energy-organisms-ecosystems

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.

http://www.nextgenscience.org/hsls-meoe-matter-energy-organisms-ecosystems

Middle School

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

http://www.nextgenscience.org/msps-spm-structure-properties-matter

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.

http://www.nextgenscience.org/msps-cr-chemical-reactions

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.

http://www.nextgenscience.org/msps-cr-chemical-reactions

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.

http://www.nextgenscience.org/msls-meoe-matter-energy-organisms-ecosystems

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.

http://www.nextgenscience.org/msls-sfip-structure-function-information-processing

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.

http://www.nextgenscience.org/msls-meoe-matter-energy-organisms-ecosystems

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.

http://www.nextgenscience.org/msls-meoe-matter-energy-organisms-ecosystems

Target Performances for Each Activity

All Carbon TIME units are organized around a common purpose: assessing and scaffolding students’ three-dimensional engagement with phenomena. Every Carbon TIME activity has its specific expectation for students’ three-dimensional engagement with phenomena, what we call its target performance. Each activity also includes tools and strategies that teachers can use to asses and scaffold the target performance in rigorous and responsive ways.

The target performances for each activity in the Plants unit are listed in the table below.

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Activity	Target Performance
Pre-Lesson 1: Investigation Setup
Pre-Activity 0.2GL: Keeping Track of Solids in Mixtures	Students will distinguish between solid mass (or dry mass) and total mass of materials consisting of water mixed with solid materials and use measurement techniques to determine the mass of solids in the mixtures.
Pre-Activity 0.2GL: Plant Growth Investigation Setup	Students will make initial measurements of the dry mass of radish seeds and growth media and start plants growing.
Pre-Activity 0.2PT: Plant Growth Investigation Setup	Students will make initial measurements of the dry mass of radish seeds and growth media and start plants growing.
Lesson 1 – Pretest and Expressing Ideas (students as questioners)
Activity 1.1: Plants Unit Pretest	Students show their initial proficiencies for the overall unit goal: Questioning, investigating, and explaining how matter and energy move and change as plants live, move, and grow.
Activity 1.2: Expressing Ideas and Questions about How Plants Grow	Students ask and record specific questions about changes in matter and energy in response to the unit driving question: How do you think that a plant grows, moves, and functions?
Lesson 2 – Foundations: Zooming into Organisms (students developing foundational knowledge and practice)
Activity 2.1: Zooming into Plants, Animals, and Decomposers	Students “zoom in” to animals, plants, and decomposers, describing how all of these organisms are made of cells with special structures and functions.
Activity 2.2: Molecules Cells Are Made of	Students use food labels to describe molecules in animal, plant, and decomposer cells: large organic molecules (carbohydrates, proteins, and fats), as well as water, vitamins, and minerals.
Activity 2.3: Molecules in Cells Quiz	Students complete a quiz to assess their understanding of the molecules in cells and how to identify which molecules store chemical energy.
Activity 2.4: Questions about Plants	Students observe their growing radish plants and pose questions about plants to prepare for their upcoming investigation.
Lesson 3 – Investigating Growing Radish Plants (students as investigators and questioners)
Activity 3.1: Predictions and Planning about Radish Plants Growing	Students develop hypotheses about how matter moves and changes and how energy changes when radishes move, and grow and make predictions about how they can use their investigation tools—digital balances and BTB—to detect movements and changes in matter.
Activity 3.2 (PT or GL): Observing Plants’ Mass Changes, Part 1	Students harvest their radish plants and dry down the plants and the paper towel or gel in preparation for Activity 3.4.
Activity 3.3: Observing Plants in the Light and Dark	Students observe how plants affect BTB in the light and dark, identify patterns in data, and reach consensus with other groups about their results.
Activity 3.4 (PT or GL): Observing Plants’ Mass Changes, Part 2	Students measure the dry weight of harvested plants and of paper towels or gel, identify patterns in data, and reach consensus with other groups about their results.
Activity 3.5: Evidence-Based Arguments about Plants	Students (a) use data from their investigations to develop evidence-based arguments about how matter moves and changes and how energy changes when plants grow, move, and function; and (b) identify unanswered questions about matter movement and matter change that the data are insufficient to address.
Lessonn 4: Explaining How Plants Make Food, Move, and Function (students as explainers)
Activity 4.1: Molecular Models for Potatoes Moving and Functioning: Cellular Respiration	Students use molecular models to explain how carbon, oxygen, and hydrogen atoms in glucose and oxygen molecules are rearranged into carbon dioxide and water in a potato plant’s cells.
Activity 4.2: Explaining How Plants Move and Function: Cellular Respiration	Students explain how matter moves and changes and how energy changes during cellular respiration in a potato plant’s cells.
Activity 4.3: Molecular Models for Potatoes Making Food: Photosynthesis	Students use molecular models to explain how carbon, oxygen, and hydrogen atoms in carbon dioxide and water molecules are rearranged into glucose and oxygen in a potato plant’s leaf cells.
Activity 4.4: Explaining How Plants Make Food: Photosynthesis	Students explain how matter moves and changes and how energy changes during photosynthesis in a potato plant’s leaf cells.
Lesson 5 – Explaining How Plants Grow (students as explainers)
Activity 5.1: Tracing the Process of Potatoes Growing: Biosynthesis	Students “zoom in” to the structure and function of a potato plant’s systems and cells, tracing atoms and energy.
Optional Activity 5.2: Molecular Models for Potatoes Growing: Biosynthesis	Students use molecular models to explain how plants make monomers from glucose and minerals and monomers are linked into polymers during biosynthesis.
Activity 5.3: Explaining How Potato Plants Grow: Biosynthesis	Students explain how matter moves and changes and how energy changes during biosynthesis in a potato plant’s cells.
Lesson 6 – Explaining Other Examples of Animals Growing, Moving, and Functioning (students as explainers)
Activity 6.1: Explaining Other Examples of Plants Growing, Moving, and Functioning	Students develop integrated accounts of how other plants (Lodgepole pine, Spartina marsh grass, prickly pear cactus) grow, move and function through the processes of photosynthesis, cellular respiration, and biosynthesis.
Activity 6.2: Functions of All Plants	Students develop integrated accounts of how all plants grow, move and function through the processes of photosynthesis, cellular respiration, and biosynthesis.
Activity 6.3: Comparing Plants and Animals	Students compare how matter moves and changes and how energy changes in a growing tree vs. a growing child, connecting macroscopic observations with atomic-molecular models and using the principles of conservation of matter and energy.
Activity 6.4: Plants Unit Posttest	Students show their end-of unit proficiencies for the overall unit goal: Questioning, investigating, and explaining how plants move and change matter and energy as they live, move, and grow.

Materials List

Download Zip File of All Unit Materials

Materials to Purchase PDF

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

Materials Available on the Website