Chapter 10 · Unit 4: Earth's Systems · Segment 2

Energy in Earth's Systems

How does energy flowing from the Sun and from Earth's interior set rock, water, air and living things in motion?

MS-ESS2-1 · assessesMS-ETS1-4 · practiceMS-ESS2-6 · supportsMS-ESS2-4 · supportsMS-ESS2-2 · supportsMS-LS2-3 · supports Textbook pp. 128–139 1 presentation · 10 worksheets · 3 labs
Student bundle (no keys) (9.7 MB)Teacher bundle (password) (13.3 MB)

Overview

Students figure out why matter keeps moving inside a planet that has no motor: energy flowing out of Earth's hot interior and energy arriving from the Sun change the density of rock, water and air, and gravity then pulls the denser material down while the less dense material is pushed up. That one mechanism, convection, turns over the solid mantle over hundreds of millions of years, drives a global loop of ocean water, and builds the air cells that carry weather. Students sort Earth into four overlapping systems, trace energy and matter across the borders between them, and see that in the living world matter cycles but energy flows through and leaves as heat. The chapter closes with Biosphere 2, a sealed physical model of Earth's systems whose falling oxygen showed how testing a model exposes what the next design must fix.

Estimated class time: presentation about 133 minutes · worksheets about 420 minutes in total · labs 3 sessions. Six to seven 50-minute periods: one for the phenomenon and the four systems; two for energy transfer, density and convection with the tank model; one for the ocean and atmosphere loops; one for the systems model across all four spheres; one for Biosphere 2 and the borehole decision; one for synthesis and mastery.

Phenomenon

The cold draft from a window that is shut

On a cold January morning the classroom heater sits against the far wall, and the window on the opposite wall is closed and locked. Still, the students in the row by the window feel a steady cold draft sliding down the glass and across their ankles. The teacher lights a stick of incense and holds it near the sill: the smoke drifts down the window, creeps along the floor toward the heater, rises up the warm wall and spreads along the ceiling back toward the window. Nothing is blowing. No fan is on. Yet the air in the room is circulating in a slow, silent loop.

Notice and wonder prompts

  • What path does the smoke take, and where does it move fastest and slowest?
  • If no fan is pushing the air, what is making it move?
  • Why does the draft feel cold near the floor and not near the ceiling?
  • Would the loop still run if the heater were turned off? If the window were as warm as the heater?

Learning targets

  • I can name Earth's four major systems, say what belongs to each, and give examples of parts that belong to more than one.
  • I can explain how heating and cooling change density and how gravity then turns those density differences into a convection cell.
  • I can tell conduction, convection and radiation apart and say which one moves energy in a given situation.
  • I can trace where each system gets its energy, the Sun or Earth's interior, and follow energy and matter across the borders between systems.
  • I can explain why matter cycles in the biosphere but energy flows through it and leaves as heat.
  • I can describe how data from a physical model such as Biosphere 2 reveal problems that the next version of the model must fix.

What shows the learning happened

  • A labeled convection-cell diagram for one Earth system that names the energy source, where material warms and expands, where it cools and contracts, and the role of gravity in each leg of the loop.
  • A completed Lab 1 recording sheet with timed dye-plume rises at two temperatures, a control run with room-temperature dye, and a written decision about whether heat or dye caused the motion.
  • A string-and-card systems model (Lab 2) with every connection tagged energy, matter or both, the two energy inputs and the one energy output identified, and at least three cross-system links.
  • A data claim (Lab 3) that computes a temperature gradient in degrees per kilometer, extrapolates the depth needed to reach a target temperature and explains a non-linear profile using convection.
  • A CER paragraph (W6) arguing from sealed-jar oxygen and carbon dioxide data that decomposers in the soil, not the plants or a leak, consumed the oxygen, and proposing the next test of the model.
  • A short written response that correctly says matter cycles in the biosphere while energy flows through it and leaves as heat, and that repairs a diagram arrow labeled 'energy' pointing from decomposers to producers.

Key vocabulary 12 terms

geosphereThe system made of all of Earth's rock and metal, from the ground under your feet to the center of the planet. It includes the crust, the mantle and the core.Lava pouring from a volcano is geosphere material that convection has carried up from deep inside the planet.
hydrosphereThe system made of all of Earth's water in every form: oceans, lakes, rivers, groundwater, ice sheets, cloud droplets and invisible water vapor.Oceanographers track the hydrosphere's slowest loop by following cold, salty water that sinks near Antarctica.
atmosphereThe layer of gases that gravity holds around Earth, mostly nitrogen and oxygen. It thins out gradually with height instead of ending at a sharp edge.Almost all weather happens in the lowest, densest part of the atmosphere, within about 10 to 15 kilometers of the surface.
biosphereThe system made of every living thing on Earth plus all the places in rock, water and air where life can survive.Bacteria living in rock a kilometer underground extend the biosphere deep into the geosphere.
crustThe outermost layer of the geosphere: a cool, brittle shell of rock that is thin next to the layers below it and the least dense. Continental crust averages about 35 km thick; ocean crust is thinner, around 7 km.A borehole a few kilometers deep barely scratches the crust, yet the rock at the bottom is already noticeably warmer.
mantleThe thick layer of hot rock between the crust and the core. It is solid, yet over millions of years it creeps and circulates like an extremely stiff putty.Mantle rock rising beneath an ocean ridge moves only a few centimeters per year, about as fast as fingernails grow.
coreEarth's center, made mostly of the metals iron and nickel. The outer core is liquid; the inner core is solid because of the enormous pressure. It is the densest and hottest layer.Heat leaving the core keeps the bottom of the mantle warmer than the top, which is what keeps mantle convection going.
densityThe amount of mass packed into a given volume, such as grams per cubic centimeter. Warming a material usually spreads its particles out and lowers its density.A balloon of warm air rises because its density is lower than the density of the cooler air around it.
conductionEnergy passing from particle to particle through a material, or between materials that touch, always from the warmer side to the cooler side, without the material itself moving.Heat travels through the solid crust toward the surface mainly by conduction, which is why rock gets steadily warmer with depth.
convectionEnergy carried along by moving matter: warmer, less dense material is pushed upward as cooler, denser material sinks under gravity, forming a loop called a convection cell.Convection in the ocean moves warm surface water toward the poles and cold deep water back toward the equator.
radiationEnergy traveling as light, including invisible infrared light. Radiation needs no matter to carry it, so it can cross the empty space between the Sun and Earth.Earth loses energy to space by radiation, sending infrared light outward from the top of the atmosphere.
closed systemA system that matter cannot enter or leave. Energy, such as sunlight and heat, can still cross the boundary.Biosphere 2 was built as a closed system for matter, but sunlight poured in through its glass every day.

Standards alignment

California NGSS, Grade 7 Preferred Integrated Course Model. Each entry says whether this chapter's work assesses the performance expectation, gives practice toward it, or supports it as background; the resource lists below repeat this for every worksheet and lab.

MS-ESS2-1Assesses: the energy-flow half: modeling how energy from Earth's interior and the Sun drives convection and the movement of Earth's materialsCA Grade 7

Develop a model to describe the cycling of Earth’s materials and the flow of energy that drives this process.

Students develop and revise models (a convection-cell diagram, a tank model in Lab 1, a string-and-card systems model in Lab 2) that describe how energy flowing from the interior and from the Sun drives the cycling of rock, water and air. The clarification statement's named processes (melting, crystallization, weathering, deformation, sedimentation) are developed in Lesson 17, so this chapter supplies evidence for the energy-flow part of the PE and sets up the materials-cycling part.

Assessment boundary: Assessment does not include the identification and naming of minerals.

MS-ETS1-4Practice toward: using data generated by a model to decide what to modifyCA Grade 6-8

Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.

The Biosphere 2 strand asks students to read oxygen data from a physical model, propose what went wrong and decide what to test next. Students analyze and propose iterations rather than building a testable model themselves (W9 asks for a design), so the role is practice.

MS-ESS2-6Supports: the unequal-heating origin of atmospheric and oceanic convectionCA Grade 6

Develop and use a model to describe how unequal heating and rotation of the Earth cause patterns of atmospheric and oceanic circulation that determine regional climates.

This is a Grade 6 PE in the California integrated sequence. The chapter explains why air and ocean water circulate (stronger sunlight near the equator, cooling near the poles) as examples of convection, but does not develop latitude bands, the Coriolis effect or regional climates, so it supports rather than assesses the PE.

Assessment boundary: Assessment does not include the dynamics of the Coriolis effect.

MS-ESS2-4Supports: evaporation, condensation and precipitation as the atmosphere-hydrosphere linkCA Grade 6

Develop a model to describe the cycling of water through Earth’s systems driven by energy from the sun and the force of gravity.

This is a Grade 6 PE in the California sequence. The atmosphere section traces water evaporating, rising in warm air, condensing into clouds and falling under gravity; the chapter uses it as an example of energy and matter crossing between systems and leaves the full water cycle to Lesson 18.

Assessment boundary: A quantitative understanding of the latent heats of vaporization and fusion is not assessed.

MS-ESS2-2Supports: the deep-energy source behind surface changeCA Grade 7

Construct an explanation based on evidence for how geoscience processes have changed Earth’s surface at varying time and spatial scales.

Volcanic eruptions and geysers appear here as surface evidence that energy and matter move outward from Earth's interior. Students do not yet construct explanations of surface change at different scales; that work belongs to Lesson 11.

MS-LS2-3Supports: energy flows and matter cycles through organismsCA Grade 7

Develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem.

The biosphere section restates the Lesson 6 idea that energy enters as sunlight, passes from producers to consumers and leaves as heat, while decomposers return matter. The chapter uses it to contrast energy flow with matter cycling across all four systems rather than to assess ecosystem models.

Assessment boundary: Assessment does not include the use of chemical reactions to describe the processes.

Science and engineering practices

  • Developing and Using Models. Students build a tank convection model (Lab 1), a string-and-card systems model of energy and matter flows (Lab 2), draw and revise convection-cell diagrams (W4), and evaluate Biosphere 2 as a physical model with limits.
  • Analyzing and Interpreting Data. Students time dye plumes at two temperatures (Lab 1), compute plume speeds and the mantle's time scale (W5), compute temperature-with-depth gradients from borehole data (Lab 3), and read Biosphere 2 oxygen data to find when and why a model failed.
  • Constructing Explanations. Students explain the window draft, the sinking of cold salty water and the mantle's slow flow using density, gravity and energy transfer, argue from Lab 1's control run that temperature, not dye, moved the water, and write a CER from sealed-jar data on what consumed the oxygen (W6).

Disciplinary core ideas

  • ESS2.A Earth Materials and Systems. All of Earth's processes result from energy flowing and matter cycling within and among the planet's systems; the energy comes from the Sun and from Earth's hot interior; convection moves both energy and matter in the mantle, the ocean and the air.
  • PS3.B Conservation of Energy and Energy Transfer. Energy moves spontaneously from warmer to cooler regions by conduction, convection and radiation; students use these three mechanisms to explain every example in the chapter.
  • ETS1.B Developing Possible Solutions. Biosphere 2 shows that a physical model must be tested and that test data drive the next modification; students practice reading such data and proposing the next test.

Crosscutting concepts

  • Energy and Matter. Students track energy inputs (Sun, interior), energy outputs (infrared radiation to space) and matter loops across the four systems, and distinguish energy that flows through the biosphere from matter that cycles within it.
  • Systems and System Models. Students define system boundaries, name inputs and outputs, and judge what a tank, a string model or a sealed glass building can and cannot show about the real Earth.
  • Cause and Effect. Students build the causal chain heating to lower density to gravity-driven sinking of denser material to circulation, and use it to predict what stops a convection cell.

Presentation 27 slides

Energy in Earth's Systems: what keeps a planet moving. Original, editable slides with speaker notes: a phenomenon opener, learning targets, the chapter's concepts with diagrams, vocabulary in context, 4 checks for understanding, 2 discussion prompts, an application task, a misconception check, a synthesis and an exit ticket.

PowerPoint (editable)Slides PDFSpeaker notes PDFSpeaker notes (web)

Worksheets 10 of 10

Ten different tasks, one per instructional blueprint. Each has a student PDF (low ink, US Letter), an editable DOCX, an HTML preview, and a separate teacher answer key with reasoning.

First page of Four Spheres, Three Ways to Move Energy: Sorting the Terms
Worksheet 2 · Vocabulary in action

Four Spheres, Three Ways to Move Energy: Sorting the Terms

I can sort parts of Earth into the systems they belong to, tell conduction, convection and radiation apart in new situations, and use density and gravity to explain why heated matter moves.

35 minindividualBuilds understandingIndependent practiceWriting MS-ESS2-1 · practice
Student PDFStudent DOCXPreview
Teacher only
Answer key PDFAnswer key DOCXKey preview
First page of How Fast Does a Plume Rise? Convection Speed and Earth's Layers
Worksheet 5 · Data and graphing

How Fast Does a Plume Rise? Convection Speed and Earth's Layers

I can calculate convection speed from a teaching dataset, graph how it depends on the temperature difference, and use real layer thicknesses to see why mantle convection takes millions of years.

45 minindividualPracticeData analysisIndependent practice MS-ESS2-1 · practice
Student PDFStudent DOCXPreview
Teacher only
Answer key PDFAnswer key DOCXKey preview
First page of Follow the Energy: A Twelve-Card Jigsaw Across Earth's Systems
Worksheet 8 · Collaborative investigation

Follow the Energy: A Twelve-Card Jigsaw Across Earth's Systems

I can work with a team to trace the energy behind twelve real events to its source, name the chain of transfers it used, identify which Earth systems it crossed, and defend our map to another group.

50 minjigsawPracticeCollaborationDiscussionVisual modeling MS-ESS2-1 · practiceMS-ESS2-6 · supportsMS-LS2-3 · supports
Student PDFStudent DOCXPreview
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First page of Design Challenge: A Sealed Mini-World That Survives Twenty-One Days
Worksheet 9 · Transfer and design

Design Challenge: A Sealed Mini-World That Survives Twenty-One Days

I can define criteria and constraints for a sealed model biosphere, use data from earlier prototypes to choose a design, plan the data my model will generate, and justify my decisions with energy and matter reasoning.

55 minpairsExtensionEngineering designData analysisWriting MS-ETS1-4 · practiceMS-ETS1-1 · practiceMS-ETS1-3 · practiceMS-LS2-3 · supports
Student PDFStudent DOCXPreview
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First page of Energy in Earth's Systems: Mastery Check
Worksheet 10 · Retrieval and mastery check

Energy in Earth's Systems: Mastery Check

I can show that I know Earth's four systems and the geosphere's layers, tell the three energy transfers apart, explain convection with density and gravity, and describe how energy from the sun and Earth's interior moves matter within and between the systems.

40 minindividualAssessmentIndependent practiceWriting MS-ESS2-1 · assessesMS-LS2-3 · supportsMS-ETS1-4 · supports
Student PDFStudent DOCXPreview
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Collaborative labs 3 of 3

Three different investigation approaches. Each has a teacher guide (purpose, materials with quantities, estimated cost, prep, safety, procedure, expected observations, debrief, answer key, assessment criteria, accessibility adaptations, low-cost alternative) and a student recording sheet.

First page of the Heat or Dye? Building a Convection Cell in a Tank recording sheet
Lab 1 · Physical model

Heat or Dye? Building a Convection Cell in a Tank

When colored water is released at the bottom of a tank, what makes it rise, the dye or the temperature difference, and what does the cold side of the loop look like?

Groups of 41 session35 min activityEst. 10 to 18 per classClear plastic container, about 2 to 4 liters, at least 10 cm deep (shoebox-size food storage box or small plastic tank)Small clear vials or 30 mL medicine cupsSquares of thin plastic card or index card, about 5 cm, to cover the vials MS-ESS2-1 · practice
Recording sheet PDFRecording sheet DOCXPreview
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First page of the Strings Across the Spheres: Modeling Energy and Matter Flows recording sheet
Lab 2 · Collaborative systems modeling

Strings Across the Spheres: Modeling Energy and Matter Flows

Where does energy enter Earth's four systems, where does it leave, and why does matter keep going around while energy passes through?

Groups of 41 session40 min activityEst. 5 to 8 per classPrinted signs: Geosphere, Hydrosphere, Atmosphere, Biosphere, Sun, Earth's interior, SpaceProcess cards 1 to 15 (printed from the recording sheet, cut apart)Yellow yarn or string (energy) MS-ESS2-1 · assessesMS-ETS1-4 · supportsMS-LS2-3 · supports
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Teacher only
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First page of the Where Should Pine Ridge Drill? A Geothermal Data Decision recording sheet
Lab 3 · Data-driven decision

Where Should Pine Ridge Drill? A Geothermal Data Decision

Using temperature-with-depth data from four test holes, which site should a small town choose for a geothermal power plant, and what does each site's data reveal about how energy moves up through the crust?

Groups of 41 session42 min activityEst. 0 to 3 per classPrinted data packet (the recording sheet with the borehole table, site notes and budget)Graph paper or the printed graph gridCalculator MS-ESS2-1 · practiceMS-ESS3-1 · supportsMS-ETS1-2 · practice
Recording sheet PDFRecording sheet DOCXPreview
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Teacher guide PDFTeacher guide DOCXGuide preview

Teacher guidance

Suggested sequence (7 steps)
  1. Period 1: Presentation slides 1-6 (the window draft, targets, four systems, geosphere layers). W1 phenomenon worksheet as the opener; W2 vocabulary relationships to close.
  2. Period 2: Slides 7-11 (three transfer mechanisms, convection cell, density and gravity). Lab 1 tank convection model: groups run the control, warm and hot vials (the teacher dispenses the warm and hot water) while students time and sketch.
  3. Period 3: Slides 12-13 (cake-batter discussion, density check). Lab 1 analysis questions and debrief (heat or dye?) as the written product of the lab. W4 diagram worksheet on completing a convection-cell model.
  4. Period 4: Slides 14-19 (where the water is, the ocean loop, convection in three systems, The Geysers connection, energy-source check, the free-fall candle discussion). W3 reading passage in class or for homework.
  5. Period 5: Lab 2 systems model with string and cards (one session). Slides 20-21 (biosphere energy flow, crossing the borders) immediately after. W8 collaborative evidence sort can replace Lab 2 if floor space is limited.
  6. Period 6: Slides 22-23 (Biosphere 2 oxygen data task, physical models and iteration). W6 CER on the sealed-jar oxygen data, then Lab 3 borehole data decision (one session). W5 data worksheet (plume speed and the mantle's time scale) and W9 transfer task (design a sealed model and its test plan) as homework.
  7. Period 7: Slides 24-27 (misconception, biosphere check, synthesis, exit). W7 misconception repair, then W10 mastery as the quiz.

Materials overview: Lab 1 needs one clear container of room-temperature water per group, small vials or medicine cups with lids, food coloring, an ice tray, a thermometer and a stopwatch; the teacher dispenses warm and hot water from a kettle or urn held below 60 °C and students never handle it. Lab 2 needs index cards, two colors of yarn, tape and four printed system signs. Lab 3 needs printed data tables, graph paper and calculators. No open flames, no chemicals beyond food coloring. The incense for the phenomenon is optional; a strip of tissue paper on a pencil shows the draft direction without smoke.

Common misconceptions (5)
“Heat rises on its own; warm things simply go up.”
Why it happens: Students see smoke, steam and warm air move upward and never see the cooler material that is sinking to take its place.
Correction: Nothing about warmth makes it rise by itself. Warming lowers density, and gravity pulls the surrounding denser material down harder, which pushes the less dense material up. Without gravity there is no convection: a candle flame in free fall is a dim blue ball because no fresh air is pushed in.
“The mantle is an ocean of liquid magma, and the crust floats on it like a raft.”
Why it happens: Volcanoes erupt liquid lava, textbooks compare the mantle to cake batter, and diagrams color it orange.
Correction: The mantle is solid rock. It is hot enough to creep and deform over millions of years, moving a few centimeters per year, so it convects while staying solid. Magma forms only in small pockets where conditions let rock partly melt, mostly in the upper mantle and crust.
“Energy cycles around the biosphere the way matter does, so decomposers send energy back to plants.”
Why it happens: Food-chain diagrams, including the one in the textbook, often draw one loop labeled 'energy and matter' with an arrow from decomposers back to producers.
Correction: Matter (carbon, nitrogen, water) loops from producers to consumers to decomposers and back to producers. Energy enters as sunlight, passes along the chain, and leaves every organism as heat. Plants get new energy only from the Sun, never from decomposers.
“The Sun heats the air directly, so the air near the equator warms the way a pan warms on a stove.”
Why it happens: Sunlight is felt as warmth on the skin, and the textbook's wording can be read as the Sun warming equatorial air directly.
Correction: Most sunlight passes through clear air and is absorbed by the ground and the ocean surface. The warm surface then heats the air touching it by conduction, by infrared radiation and by convection. That is why the warmest air is at the bottom and why convection starts at the surface.
“Conduction, convection and radiation are three kinds of heat, and each situation uses only one.”
Why it happens: The three terms are introduced as separate vocabulary words with one example each.
Correction: They are three ways energy is transferred, and real situations combine them. Heat leaves the core and crosses into the mantle by conduction, moves through the mantle mainly by convection, crosses the rigid crust by conduction, and finally leaves Earth's surface by radiation and convection in the air.
Differentiation suggestions (5)
  • Multilingual learners: Pre-teach the four system names with a picture card and a one-word home-language label each; use color consistently (red for warm and rising, blue for cool and sinking) in every diagram; pair for Lab 1 so one partner narrates the plume while the other times it; provide sentence frames such as 'The ___ warms, becomes less dense, and ___.'
  • Students who need more support: Give the Lab 3 data already plotted for Site A so students compute only the gradient; supply a half-completed convection-cell diagram with the two legs labeled and ask students to add the causes; reduce Lab 2 to eight cards with the sphere of origin printed on each.
  • Students ready for extension: Ask them to explain why fresh water below 4 °C behaves backwards and what that means for lake ice, to estimate how long one mantle loop takes at 3 cm per year over 6,000 km, or to research how the Santa Rosa wastewater pipeline keeps The Geysers producing steam.
  • Students who need movement or alternative output: Run the convection cell as a floor walk: students carry 'energy' tokens, pick them up at the heater or the sunlit floor tile and drop them at the ceiling or the window; let Lab 2 be built on the floor with yarn rather than drawn; accept a narrated video of the tank plume in place of the written description.
  • Students with low vision or limited fine-motor control: Use strongly colored dye and a white backdrop behind the tank, project the tank with a document camera, provide large-print data tables with 2 cm rows, and allow the Lab 2 model to be built with thick cord and clothespins instead of string and tape.
Accuracy notes: where the textbook simplifies (16)
  • The core (pp. 129-130): the textbook calls it a rock layer and says it is hottest because of pressure from above. The core is almost entirely iron and nickel metal; the outer core is liquid and the inner core is solid because pressure raises the melting point. Its heat is left over from Earth's formation, from radioactive decay, and from the outer core slowly crystallizing. Say 'metal core,' and never say pressure makes it hot.
  • The mantle flows like cake batter (pp. 130-131): mantle rock is solid and creeps by very slow solid-state deformation, a few centimeters per year, so one convection loop takes on the order of a hundred million years or more. Use 'stiff putty over millions of years' and keep the word solid every time. Magma is a local, partial melt, not the mantle's normal state.
  • Where conduction and convection act (p. 131): energy crosses the core-mantle boundary and the rigid crust mainly by conduction; within the mantle, convection carries most of the energy. Teach the two as acting together rather than as a hand-off at one place.
  • Convection needs gravity: the textbook mentions gravity pulling dense material down, which is right, and worth stressing. Warm material does not rise on its own; it is displaced upward by denser material sinking. In free fall (the International Space Station) there is no convection and a candle flame is a small blue sphere.
  • Warm water is less dense (p. 133): true for fresh water above about 4 °C. Between 0 and 4 °C fresh water gets less dense as it cools, which is why lakes freeze from the top. Seawater of normal salinity keeps getting denser all the way to its freezing point near −2 °C. State the condition when you say it.
  • The ocean loop (p. 133, Figure 2): deep water forms where surface water is both cold and salty; sea ice forming near the poles leaves salt behind, raising density. Winds drive most surface currents. The book's single giant current is a simplified picture of the global overturning circulation, which takes roughly a thousand years for one trip.
  • Where sunlight is absorbed (p. 135): most sunlight that Earth absorbs is taken in by the ground and the ocean, not by the air. The surface then warms the air above it by conduction, infrared radiation and convection. Say 'the Sun warms the surface, and the surface warms the air.'
  • Atmosphere composition (p. 134): carbon dioxide and water vapor are compounds, not elements. Dry air is about 78% nitrogen, 21% oxygen, 0.9% argon and about 0.04% carbon dioxide (rising); water vapor varies from near zero to about 4%. Nearly all, not all, weather occurs in the lowest layer, the troposphere.
  • Thickness figures (pp. 132, 134, 137): the hydrosphere's 20 km, the biosphere's 70 km and the atmosphere's 10,000 km are rough model values with fuzzy edges. The atmosphere has no top; it fades until it merges with space. Do not assess these numbers. The geosphere values (crust about 35 km for continents, mantle about 2,865 km, core radius about 3,470 km) are close to standard figures.
  • Water shares (p. 132): about 97% of Earth's water is salty and about 2.5% is fresh; of the fresh water, roughly 69% is ice, 30% is groundwater and about 1% is surface water, with lakes and rivers a fraction of that last share. Teach the ranking, not exact percentages.
  • Energy sources (p. 137): the book names the Sun and the interior as the only two sources, with no hedge. The Moon's gravity adds tidal energy, a small third source that helps stir the deep ocean (W8 q7 raises it). Say 'nearly all.'
  • Energy in the biosphere (pp. 136, 139): the book says energy and matter are cycled through food chains and labels the decomposer-to-producer arrow 'energy and matter.' Energy flows one way and leaves as heat; decomposers return matter only. Also say 'nearly all' food chains start with sunlight, since deep-sea vent communities run on chemical energy.
  • Biosphere 2 (pp. 138-139): it was sealed to matter but open to energy, since sunlight entered through the glass and heat left. Oxygen fell from about 21% to about 14% over roughly sixteen months because soil microbes consumed it faster than plants replaced it, and much of the carbon dioxide they released was absorbed by the building's exposed concrete, which hid the cause; managers eventually added oxygen. The crew was sealed in from September 1991 to September 1993. The facility is now owned and run by the University of Arizona. Do not repeat the book's unsupported claims that it was the first artificial biosphere or that it brought colonization a big step closer.
  • Radiation (p. 129): define it as energy carried by light, including infrared, which needs no matter. Do not describe it as traveling only through 'transparent objects'; it crosses empty space. Avoid any link to radioactivity in student language.
  • Warm water in the labs and worksheets: Lab 1 uses fresh tap water, so the dyed ice melt (near 0 to 4 °C) is denser than 21 °C tank water and sinks for temperature alone; salt plays no part in the tank, unlike the polar ocean. W1 sets the cold pouch at 4 °C, where fresh water is densest, on purpose.
  • Hot-air balloon (W2 q9): the burner heats air mainly by mixing hot exhaust gases into the envelope, so a student who calls the entry step convection rather than conduction is not wrong; the key accepts either as long as density and gravity explain the lift.

Review status: reviewed · 2026-10-19 · Re-solved every numeric, multiple-choice and open item in W1-W10 and Labs 1-3; keys agree with the recomputed values. Cross-references repaired: W6 is the sealed-jar oxygen CER (not a heat-or-dye CER) and Lab 3 is the geothermal borehole decision (not a sealed-jar build); chapter sequence, SEP and evidence entries, slide links and W6/W9 teacher notes now say so. Fixed W1 q5 key (4 °C is the density maximum of fresh water, not above it), W3 q4 alternatives (rounding 0.09 to 0.1 gives 3,400, not 4,000), Lab 1 ice-melt density note (fresh melt is denser than 21 °C tank water), Lab 2 q3 entering-string count. Replaced Lab 1 q8, which duplicated W5 q8 (mantle transit time), with a tank-versus-mantle time comparison. Rewrote crust definitions that echoed the textbook's wording (chapter, slides 5-6, W2, W4) and two other short echoes (W4/W5 figure wording, W8 card 8). Slide 2 now returns to the heat-rises idea on slides 10, 11 and 19; slide 3 target links corrected. Trimmed vocabulary to 12 terms and relatedChapters to 4 per the guide; USGS bar now names salty groundwater. Added accuracy notes on fresh-water ice melt in Lab 1 and the hot-air balloon entry step in W2. Labs remain untested physically; see each lab's modelLimitations.

Source references

Verified against the student edition of Bring Science Alive! 7th Grade Integrated (Student Edition). Printed page numbers appear in the book; PDF pages are the physical pages of the 524-page scan (printed + 36). The textbook is not reproduced on this site.

SectionPrinted pagesPDF pagesUsed for
Introduction: Strokkur Geyser, the boiling pot and the lesson question128, 129164, 165Lesson question, the geyser as evidence of interior energy, the publisher's vocabulary list and standards box.
1. The Geosphere: layers, density, conduction and mantle convection130, 131166, 167Layer thicknesses for the layers diagram, the density-and-gravity mechanism of convection, Lab 1 tank model, Lab 3 borehole decision.
2. The Hydrosphere: where the water is and the ocean loop132, 133168, 169Water-share bar diagram, radiation as the Sun's delivery method, the ocean convection slide and Lab 2 cards.
3. The Atmosphere: composition and convection cells134, 135170, 171Air convection cells, the evaporation-condensation link, the phenomenon explanation, the three-systems comparison table.
4. The Biosphere: food chains and energy from the Sun136172Energy-flow versus matter-cycling diagram, misconception on the decomposer arrow, biosphere check.
Key Science Concept: The Flow of Energy and Matter Through Earth's Systems137173The two energy sources, relative thicknesses of the systems, cross-system concept map, Lab 2 systems model.
5. Modeling Earth's Biosphere: Biosphere 2 and iterative testing138, 139174, 175Physical versus conceptual models, closed system, the oxygen-data task, the ETS1-4 strand, lesson summary.

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Related chapters

Ch. 6: Food Webs and Trophic PyramidsCh. 11: Scales of Change on Earth's SurfaceCh. 16: Earth's Tectonic PlatesCh. 24: Heat, Temperature, and State Changes
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