Skip to Content

Human Energy Systems

Carbon TIME: Human Energy Systems Unit

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

The Human Energy Systems Unit supports students in using core disciplinary ideas, science practices, and cross-cutting concepts to develop scientific explanations of how different energy systems transform matter and energy as they grow, move, and function.

Follow these steps to get ready to teach the Human Energy Systems Unit

Lead Editor for 2019 Version

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

Principal Authors

Hannah K. Miller, Department of Teacher Education, Northern Vermont University

Wendy Johnson, Department of Teacher Education, Michigan State University

Jenny Dauer, School of Natural Resources, University of Nebraska-Lincoln

Beth Covitt, College of Arts and Sciences, University of Montana

Craig Kohn, Department of Teacher Education, Michigan State University

Bonnie McGill, Kansas Biological Survey, University of Kansas

Charles W. (Andy) Anderson, Department of Teacher Education, Michigan State University

Contributing Authors

Sarah Bodbyl Roels, Elizabeth Xeng de los Santos, Jennifer Doherty, Allison Freed, Bonnie McGill, Lindsey Mohan, Emily Scott, Alex Walus Beth Covitt, Jennifer Doherty, Emily Scott, Nick Verbanic


Craig Douglas

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 goal of the Human Energy Systems unit is to introduce students to carbon cycling at a global scale and the implications of human fossil fuel use for climate change. Students:

  • Investigate patterns of change in Earth systems (global temperatures, global sea levels, Arctic sea ice, atmospheric CO2) and use the Greenhouse Effect to explain how increases in greenhouse gas concentrations drive changes in other systems;
  • Explain how three key fluxes (photosynthesis, cellular respiration, combustion of fossil fuels) affect the atmospheric CO2 pool;
  • Explain how human actions affect CO2 fluxes; and
  • Predict effects of changes in human actions on the atmospheric CO2
The Research Base

Carbon is the key! In the unit, students learn to tell the story of how matter and energy are transformed as they move through human energy systems. A particularly powerful strategy for explaining how Earth 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 Large Scale Four 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 human energy systems 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 Human Energy Systems 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 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.

Human Energy Systems Unit Sequence and Decisions Table

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

The instructional model for the Human Energy Systems Unit includes two phases, described in the Unit Overview, in which students play the role of questioners, investigators, and explainers. The first phase focuses on helping students to understand, analyze, and explain multiple phenomena associated with climate change (What is happening to the planet?). The second phase focuses on global carbon cycling (What causes changes in CO2?). Across the unit, classroom discourse is a necessary part of three-dimensional Carbon TIME learning. The
Carbon TIME Discourse Routine
document provides guidance for scaffolding this discourse in lessons.

Human Energy Systems Unit Map

The core of the Carbon TIME Instructional Model 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 Human Energy Systems 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.

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 Ecosystems 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

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

  • Ecosystems: Interactions, Energy, and Dynamics. 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.

  • Ecosystems: Interactions, Energy, and Dynamics. HS-LS2-7. Design, evaluate, and refine a solution for reducing the impacts of human activities on the environment and biodiversity.
  • Earth’s Systems. HS-ESS2-2. Analyze geoscience data to make the claim that one change to Earth’s surface can create feedbacks that cause changes to other Earth systems.
  • Weather and Climate. HS-ESS2-4. Use a model to describe how variations in the flow of energy into and out of Earth’s systems result in changes in climate.

  • Earth’s Systems. HS-ESS2-6. Develop a quantitative model to describe the cycling of carbon among the hydrosphere, atmosphere, geosphere, and biosphere.

  • Earth and Human Activity. HS-ESS3-4. Evaluate or refine a technological solution that reduces impacts of human activities on natural systems.

  • Earth and Human Activity. HS-ESS3-5. Analyze geoscience data and the results from global climate models to make an evidence-based forecast of the current rate of global or regional climate change and associated future impacts to Earth systems.

  • Earth and Human Activity. HS-ESS3-6. Use a computational representation to illustrate the relationships among Earth systems and how those relationships are being modified due to human activity.

Middle School

  • MS-ESS2-1. Develop a model to describe the cycling of the Earth’s materials and the flow of energy that drives this process.
  • Earth and Human Activity. MS-ESS3-3. Apply scientific principles to design a method for monitoring and minimizing a human impact on the environment.

  • Human Impacts. MS-ESS3-4. Construct an argument supported by evidence for how increases in human population and per-capital consumption of natural resources impact Earth's systems.

  • Earth and Human Activity. MS-ESS3-5. Ask questions to clarify evidence of the factors that have caused the rise in global temperatures over the past century.

Resources You Provide

Activity 1.1

  • pencils (1 per student, for paper version)

Activity 1.2

Activity 1.3

  • pencil (1 per student)

Activity 1.4

Activity 1.5

Activity 2.1

Activity 2.2

  • Jigsaw Cards (already distributed during previous activity)

Activity 2.3

Activity 2.4

Activity 3.1

Activity 3.2

Activity 3.3

Activity 4.1

Activity 4.2

Activity 4.3

  • Markers for Tiny World Pool and Flux Activity to be used on the placement (30 per pair of students)

Activity 4.4

Activity 4.5

Activity 5.1

  • (optional) Calculator (1 per group of four students)

Activity 5.2

Activity 5.3

Activity 5.4

  • Chart paper (1 per group of four students)

Activity 6.1

Activity 6.2

Activity 6.3

  • Pencils (1 per student)