UNIT OVERVIEW: Students investigate what has made Earth the only planet in our solar system that can sustain life, revising a model after every lesson in the Performance Task Organizer (PTO). The unit ends with an evidence-based argument about which exoplanet is most likely habitable. PERFORMANCE EXPECTATIONS: HS-ESS1-1 (Sun's life span, fusion in the core → radiation), HS-ESS1-3 (stars produce elements over their life cycle), HS-ESS1-4 (orbital motion). L1 focuses on HS-ESS1-1. CCC FOCUS: #1 Patterns (empirical evidence is needed to identify patterns); #3 Scale, Proportion, and Quantity. SEP FOCUS: #1 Asking Questions (Opening), #2 Developing & Using Models, #6 Constructing Explanations. TIMING: Unit Opening = 2 days. How the Sun Works 5E = 6 days. DECK NOTE: This deck uses inline HTML (spectrum bars, callouts). Enable HTML in Marp (VS Code: markdown.marp.enableHtml; CLI: --html).

TEACHER MOVE: Show once at the launch and return to it at each lesson transition. Students should be able to say where they are in the storyline at any point. WHY THIS SLIDE: Unit coherence is the central design claim of the unit plan — "there should be a clear and explicit unit storyline that guides the sequence of activities" from the students' perspective. This deck covers L0 and L1 only. TIMING: Whole unit = 23–29 days. L0 = 2 days, L1 = 6, L2 = 7, L3 = 7–9, L4 = 1–5. NOTE: The abstracted science question for the unit is "How do stars affect the planets that orbit them?" — do NOT lead with it. The student-facing anchor question is the one that drives engagement.

PHASE GOAL: Surface student ideas about life in the solar system, build an initial model of what makes Earth habitable, tell the story of what is happening to Earth now, brainstorm solutions, launch the performance task, and build the Driving Question Board. GROUPING: Pairs, then groups of four (keep these groups — they return in L1 Evaluate). ROUTINE: Domino Discover. TIMING: 2 days. Suggested Day 1: Surfacing ideas → timeline → initial model. Day 2: Tell the Story → solutions → performance task → DQB. MATERIALS: PTO (Life in the Solar System Timeline, Initial Model, Tell the Story, Introducing the Performance Task), Planet Earth II trailer, The Hidden Impacts of Climate Change video, How Many Planets are in the Milky Way? video, poster paper, sticky notes, chart paper, DQB Cards (scaffold).

TEACHER MOVE: Show the Planet Earth II trailer. Students note species + environments. ACCESS FOR ALL: Emphasize that students only need to DESCRIBE a species — names are not required. DISCUSSION: Have several students share. Highlight the abundance and variety of species, then pose: "Is there life elsewhere in the solar system?" TIMING: ~10 min. TRANSITION: Distribute the Life in the Solar System Timeline (PTO p. 2) — pairs.

TEACHER MOVE: Pairs respond to PTO questions 1–5; a few pairs share out for each. EXPECTED STUDENT RESPONSES: Q1: mya = millions of years ago (4,600 mya = 4.6 billion years ago). Q2: Dotted box = weak evidence (Europa ocean); solid = strong evidence. Q3: 4,600 − 3,500 = 1,100 million years ≈ 1.1 billion years. Q4: water, atmosphere, gravity, precipitation, chemical building blocks, the Sun. Q5: Several places had water, but only Earth has evidence of life; life took a long time. COMMON MISCONCEPTION: Reading "4,600 mya" as 4,600 years. Have students convert one value to billions. CONNECTION: The dotted/solid distinction is an early seed for "What counts as an evidence-based claim?" in L1 Explain. TIMING: ~15 min.

TEACHER MOVE: Summarize the share-out on this slide. LOOK & LISTEN FOR (from plan): "It took over a billion years for the first life to appear on Earth and even longer for more complex life" • "The first life did not appear until several hundred million years after the formation of oceans and an atmosphere" • "There is no evidence for life anywhere else in the solar system, only evidence of water." KEY POINT: Time scale matters — this will return in L1 Evaluate (Sun's stable energy for billions of years). TRANSITION SCRIPT: "Out of all the planets in the solar system, Earth has life! Earth didn't have life for a long time and now it does. So what is it about Earth that makes it the only planet in our solar system that has sustained life?"

TEACHER MOVE: Read the anchor phenomenon aloud and introduce "habitable." EXPECTED STUDENT RESPONSES: water, right temperature, distance from the Sun, atmosphere/oxygen, gravity, the Sun's light for plants. TRANSITION: Hand out the Initial Model page (PTO p. 5).

TEACHER MOVE: Students complete individually or in pairs, then groups of four build a shared model on poster paper. SAVE THE POSTERS — revised in L1 Evaluate (Idea Carousel). CONFERRING QUESTIONS: "Are there arrows or labels you want to add?" • "What process do you think this shows?" • "Are there parts that need terms or descriptions?" • "Are there important cause-and-effect relationships you want to make clear?" • "Why did you include this component?" • "Are there other components that might be important?" IMPLEMENTATION TIP: The Earth-Sun template steers students to the solar-system scale used all unit. Don't provide it again unless a group is stuck. FORMATIVE ASSESSMENT: Note whether students treat the Sun as a passive light bulb — most won't explain HOW the Sun makes energy. That gap drives L1. NOTE: The component list on the right is optional — reveal only if groups stall; initial models should reflect student thinking. TIMING: ~25 min.

TRANSITION SCRIPT (from the plan): "While Earth has been habitable for a long time now, scientists are concerned about the stresses Earth has been experiencing in recent decades and what it means in terms of its capacity to sustain life as we know it in the future." TEACHER MOVE: Frame the video and the three texts as one task — the class is collaboratively telling the story of what is happening to Earth. WATCH FOR: Students jumping to causes or solutions. Redirect to the phenomenon: what is happening, not why or what to do. TIMING: ~3 min, then straight into the video.

TEACHER MOVE: Show The Hidden Impacts of Climate Change (prompt: What details tell the story of what is starting to happen to planet Earth?). Students silently read Texts #1–3 once, then reread and circle three important details. Remind students to focus on the phenomenon, not their hypotheses. CONFERRING QUESTIONS: "What is happening to planet Earth?" • "Why is this detail important?" • "Did your group circle the same details?" • "How did your group agree on the overall story?" DIFFERENTIATION: Break it into steps — read with no writing, then reread and annotate on sticky notes. TIMING: ~25 min.

TEACHER MOVE: Groups agree on their five most important details and one overall story; take a few shares. EXPECTED RESPONSE (sample student work): "Earth is basically becoming a place that is less habitable… carbon dioxide increase is causing global warming, which is causing sea level to rise, species to go extinct, and insects and disease carriers… might be more common in New York." WATCH FOR: Details not in the texts (e.g., population) — accept, but ask for the source. TRANSITION: Independent brainstorm of solutions (two guiding prompts on the slide).

TEACHER MOVE: Guiding prompts: (1) What are your initial ideas for what we can do to ensure the survival of humans and other species? (2) What if humans and many species can no longer live on Earth — what can humans do to survive as a species? ROUTINE — Domino Discover: groups share in turn; chart ideas; listen to gauge readiness to move on. KEY POINT: If "find another planet" doesn't come up, introduce it as a solution scientists are exploring. It becomes the performance task. NOTE: Reveal the right column only after the class share. Worth saying: exoplanet research doesn't replace protecting Earth. TIMING: ~15 min.

ROUTINE — Domino Discover: first use in the unit (unless you used it at the Anchor Phenomenon launch). It surfaces students' thinking to the whole class AND to the teacher, lets students learn from each other, and lets you assess readiness to move to the next phase. See the Unit 1 Teacher Guide. WHY A SLIDE: Domino Discover is used three times across L0–L1 (Brainstorm Solutions, Explore summary, DQB revisit), but unlike Rumors, Class Consensus Discussion, and Idea Carousel it previously had no student-facing steps. Post it. TEACHER MOVE: Chart as they go. Resist summarizing for them.

TEACHER MOVE: Students read "Introducing the Performance Task" and ask clarifying questions. Show the first 2:50 of "How Many Planets are in the Milky Way?" KEY POINT: There are a tremendous number of planets to investigate, so we need CRITERIA for what makes a planet Earth-like. Our initial models are the start of those criteria. CONNECTION: Stars (L1 How the Sun Works, L2 Star Life Cycles) and planets/orbits (L3) feed the final argument. TIMING: ~15 min.

TEACHER MOVE: Students independently write questions; small groups categorize onto chart paper (can be whole-class). CONFERRING POINTS: "Why do these questions belong together?" • "What category connects these?" • "Can you write an umbrella question?" • "Now that you see them grouped, do new questions come up?" DIFFERENTIATION: Provide DQB Cards (scaffolded question set) to groups that struggle — but still ask for some of their own questions. SEP #1: Ask questions that arise from careful observation of phenomena. TIMING: ~25 min.

TEACHER MOVE: Use to support categorizing only if needed — student-generated categories come first. CONNECTION: The "star" category launches L1 (How the Sun Works). Planet features/orbits → L3. Keep the DQB posted; it is revisited at the end of L1 Evaluate.

LESSON OVERVIEW (6 days): Students investigate their DQB Sun questions ("Does the exoplanet have a Sun like ours?"). They use light spectra to determine the Sun's composition (H and He), then use the scale of energy and time to argue that nuclear fusion — not chemical combustion — releases the Sun's energy. They revise their habitability models and predict the Sun's future. PE: HS-ESS1-1. DCIs: ESS1.A, PS3.D, PS4.B. CCC #1 Patterns, CCC #3 Scale. SEP #2, SEP #6. SUGGESTED PACING: Day 1 Engage • Days 2–3 Explore • Days 3–4 Explain • Day 5 Elaborate • Day 6 Evaluate.

PHASE GOAL: Students connect DQB Sun questions to how the Sun provides light and heat, share initial claims about how the Sun releases energy on a huge scale, and recognize a need to investigate the Sun's composition. GROUPING: Individual → turn-and-talk → whole class. ROUTINE: Rumors (first use in the unit). TIMING: ~1 class period. MATERIALS: How Does the Sun Provide Energy handout, sticky notes, chart paper, NASA footage of the Sun.

TEACHER MOVE (launch): Remind students of DQB Sun questions ("Does the exoplanet have a sun like ours?"). Ask why they asked them. Listen for: the Sun gives heat (not too hot/cold) and light for plants (food). Say: "To figure out whether the exoplanet has a sun like ours, we need to understand what our Sun is like." EXPECTED RESPONSES after video: looks like lava, flames shooting out, explosions, some parts darker, seems to be gas. NOTE: Reveal the left-column bullets only after students jot their own ideas. TIMING: ~10 min.

TEACHER MOVE: Show after students jot their own ideas about the Sun. Tell them the telescope enhances the images so we can see more detail of the Sun's appearance and behavior, and that the enhancement makes it appear colors other than its actual color. EXPECTED RESPONSES: looks like lava • flames shooting out • there are explosions in it • some parts are darker • it seems to have gas in it. DO NOT CORRECT: "flames" and "explosions" are exactly the ideas the Elaborate phase is designed to test. Record them. TIMING: ~5 min.

TEACHER MOVE: Students read the phenomenon at the top of "How Does the Sun Provide Energy?" ACCURACY NOTE: The packet's 2.41 × 10^30 MeV/s is an exponent typo. Sun's luminosity = 3.83 × 10^26 W = 2.39 × 10^39 MeV/s. At the packet value the Sun would release ~4 × 10^17 J/s — LESS than one day of world energy use — so the packet's comparison only works with the corrected number. Decide whether to have students correct their packets now. MATH (if students ask): 3.8×10^26 J ÷ 1.6×10^18 J/day ≈ 2.4×10^8 days ≈ 650,000 years. KEY POINT: The Sun has done this every second for billions of years. CONNECTION: This quantity is the Sun's luminosity — don't name it yet; it's central in the next 5E.

TEACHER MOVE: Partners discuss before the individual brainstorm. ACCESS FOR ALL: Connecting to a familiar high-energy phenomenon helps every student generate an initial idea about the Sun. NOTE: Reveal examples only after pairs share. TIMING: ~5 min.

TEACHER MOVE: Individual brainstorm (2–5 ideas) with the observation behind each. EXPECTED STUDENT RESPONSES: burning ball of gas; explosions inside; chemicals (H, He) reacting; nuclear reactions; it's so big it has lots of fuel. COMMON MISCONCEPTION: "The Sun is on fire / burning." Record it — do NOT correct it. The Elaborate phase tests combustion vs. fusion. TRANSITION: Rumors.

ROUTINE — Rumors (first use in unit): low-stakes surfacing of all students' initial ideas. After independent brainstorming, students share their most-confident idea with several classmates, listen for trends, and report trends to the class. See the Unit 1 Guide. TEACHER MOVE: Categorize ideas on the poster (e.g., burning/fire; explosions; chemical reactions; nuclear; size/fuel; other). LOOK & LISTEN FOR: "burning ball of gas," "explosions," "made of chemicals (H or He) reacting," "energy stored in atoms and molecules" (MS.PS1.B, CCC #5 MS). ACCESS FOR ALL: Honor ideas from diverse cultural backgrounds; documenting them lets everyone track how ideas change. CLASSROOM SUPPORT: Keep the poster up for the whole 5E.

TEACHER MOVE: Ask "How do you normally figure out how something works?" then "How can we investigate further — what can we observe about the Sun from Earth?" LISTEN FOR: study the Sun's light waves (MS.PS4.B), use a space telescope, look for patterns in data (CCC #1 MS), use a prism. KEY POINT: Introduce that scientists use a spectrometer to get more information about light, and special telescopes to observe light from objects in space. IMPLEMENTATION TIP: Students know we can look at the Sun with a telescope, but not that light tells us about the inside of the Sun. "Take it apart" doesn't work for very distant objects. TRANSITION: "Next we'll investigate sunlight to figure out what the Sun is made of and how it works."

PHASE GOAL: Students learn how a spectroscopy telescope works (simulator), then analyze spectra from the Sun and lab gases for empirical evidence of patterns. GROUPING: 2–3 students per laptop. ROUTINE: Domino Discover (whole-class investigation summary). TIMING: ~1.5 class periods. MATERIALS: Light from the Sun Investigation, Making Sense (See-Think-Wonder), Investigation Rubric, Three Views Spectrum Demonstrator simulation; optional handheld spectroscopes. LAUNCH: "We can't take the Sun apart. First we'll learn about a tool for observing it from far away, then we'll look at data gathered with that tool." Ask what makes this an investigation — revisit at the end.

TEACHER MOVE (launch, from the plan): Remind students that at the end of Engage they surfaced that we cannot investigate the Sun by taking it apart. Preview the flow, then ask them to consider what makes this process an investigation — and tell them you will return to it. WHY A SLIDE: The plan poses this question at launch and says to discuss it at the end; it needs to be visible both times. See the "Wrapping Up the Investigation" slide at the end of Explore. MATERIALS: Investigating Light from the Sun handout (packet Part B), Investigation Rubric. ACCESS FOR ALL: If handheld spectroscopes are available, let students look at a bulb first and share out. This evens the playing field before the simulator.

TEACHER MOVE: Brief refresher — students know "rainbow" but may not recall "spectrum." It's fine to remind them; this isn't the term being sense-made in this 5E. ACCESS FOR ALL: If you have handheld spectroscopes, let students look at a bulb and share what they see. EXPECTED RESPONSES (Part 1 Q1–2): "A full rainbow, violet to red, no gaps." "The prism spread the white light into all its colors." NOTE: Consider showing this slide AFTER students complete Q1–2 in the simulator so they discover it themselves.

TEACHER MOVE: Students work Part 1 Q1–4 with the simulator. Let them make sense of it independently. EXPECTED STUDENT RESPONSES (Q4): "Something in the cloud blocked some of the light — that's why you see black lines." "Some light got trapped in the cloud." "No matter where the light comes from, the colors are in the same order." CONFERRING QUESTIONS: "What happened to the white light in the spectroscopy telescope?" • "Does the spectrum look the same when it passes through the hydrogen gas?" • "Was all light able to pass through?" • "What happened to the missing light?" MISCONCEPTION: The sample student work says "dust cloud" — it's a GAS cloud. Push from "blocked" to "absorbed at specific wavelengths" (a wall blocks all colors; a gas removes only particular ones). NOTE: The lines drawn here are hydrogen's (~410, 434, 486, 656 nm) — the simulator's default cloud. Show the key-idea box after students answer.

TEACHER MOVE: Optional extension slide. In the simulator's third view (telescope looking at the cloud from the side, not in line with the bulb), students see bright colored lines on black at the SAME wavelengths as the dark lines. KEY POINT: This matters later: the Part 3 comparison chart is titled "Emission Spectra of Some Elements from Stars" — it works because emission and absorption lines are at the same wavelengths. ALL THREE use hydrogen's lines: ~410, 434, 486, 656 nm. DIFFERENTIATION: Extension for students who finish Part 1 early.

TEACHER MOVE: Launch Part 2. Students answer Q1–2. EXPECTED STUDENT RESPONSES: Q1: "All three are identical. The dark lines are above the same wavelength numbers (~410, 434, 486, 656 nm) every time." Q2: "Light from inside the Sun passes through the Sun's gases, which absorb certain colors — just like the simulation. The gases don't change, so the pattern doesn't change." KEY POINT: It seems obvious the Sun's light is the same each time — the point is that we have EVIDENCE for the consistency. Push for numbers: "How do you know the lines are in the same place?" CCC #1 HS element: empirical evidence is needed to identify patterns. ACCURACY NOTE: These packet spectra show only hydrogen's four lines. Helium evidence comes from the Part 3 comparison chart.

TEACHER MOVE: Students examine the lab table (PTO/packet p. 7) and answer Q1. EXPECTED RESPONSE: "Within each gas, all three samples have lines at exactly the same wavelengths — a repeatable signature. Different gases have lines in different places. Repeatable + unique = a fingerprint we can use to identify the element." CONFERRING: "Was all light able to pass through each gas?" "What happened to the missing light?" Remind students each sample is a GAS. DIFFERENTIATION: Don't cut the struggle short. Offer a ruler or index-card edge to line up lines, or cut out strips. NOTE: Line positions on this slide use real wavelengths (H Balmer: 410.2, 434.0, 486.1, 656.3; He: 402.6, 412.1, 438.8, 447.1, 471.3, 492.2, 501.6, 587.6, 667.8).

TEACHER MOVE: Students use the "Spectra of Sun and Elements from the Lab" chart (packet p. 8) — that chart also includes carbon, nitrogen, oxygen, and silicon. EXPECTED RESPONSE: "Every Sun line lines up with a hydrogen line (656, 486…) or a helium line (588, 447…). The Sun's spectrum = hydrogen + helium combined. Carbon, nitrogen, oxygen, and silicon patterns are not there (e.g., oxygen's 600–650 nm cluster is missing). The Sun is probably made of hydrogen and helium." PLAN INCONSISTENCY: The plan's Look & Listen For mentions lithium/sodium — listen for "not nitrogen or oxygen" instead. SUBJECT CONTEXT: The real Sun is ~73% H, ~25% He by mass, ~2% heavier elements; the real solar spectrum has thousands of lines (iron, sodium, …) — these data are simplified. Helium was discovered IN THE SUN (1868, a yellow line at 587.6 nm) before it was found on Earth — named for Helios. NOTE: Hide the Sun-strip annotation until after students answer.

TEACHER MOVE: Individual See-Think-Wonder, then group discussion, then Domino Discover — one key understanding per group. Push for empirical evidence ("which wavelengths?"). READY FOR EXPLAIN WHEN THESE SURFACE: lines for each gas appear above the same wavelength • each gas absorbs differently • Sun's lines match H and He • Sun is probably H and He, not N or O. If not, re-display the simulator/spectra and use conferring questions. INTEGRATING 3D: First explicit touch of CCC #1 Patterns; connects to SEP #6 (claims based on empirical evidence). ACCESS FOR MULTILINGUAL LEARNERS: Domino Discover provides comprehensible input from peers. IF ASKED WHY (beyond assessment boundary): Electrons in atoms can only have certain energies, so an atom absorbs only photons that match a jump between levels. Different elements → different levels → different lines (PS4.B). WRAP-UP: Investigation Rubric (self + partner). Revisit "What made this an investigation?" NOTE: Reveal table cells progressively after students share.

TEACHER MOVE: Close the Explore phase by returning to the launch question and completing the Investigation Rubric (self + partner). WHY A SLIDE: The plan says to "come back and discuss this at the end of the activity" — previously this lived only in presenter notes. FORMATIVE: Disagreements between self- and partner-scores are the useful part. Ask a pair to explain one. CCC #1 HS element: empirical evidence is needed to identify patterns — the key-idea box is the student-facing version of that element. TRANSITION: "We have a pattern. Now let's use it to make a claim."

PHASE GOAL: Students use patterns from empirical evidence in spectra to support a claim about the Sun's composition, then reach class consensus. GROUPING: Pairs. ROUTINE: Class Consensus Discussion (first time — focus on the process). LITERACY: Sequence Chart; Claim-Evidence-Reasoning (CER). TIMING: ~1–1.5 class periods. MATERIALS: Spectra Sequence Chart cards, Determining the Composition of the Sun, Summary Task, "What Counts as an Evidence-Based Claim?" poster, "How does the Sun work?" poster. LAUNCH: "What are we trying to figure out?" (Does the exoplanet have a Sun like ours?) Point to the "How does the Sun work?" poster.

TEACHER MOVE: Facilitate a class discussion using shared experiences from Engage and Explore. Build the list from student ideas — this slide shows the likely result; reveal only after the discussion. LOOK & LISTEN FOR: Ideas influenced by how evidence works in history/humanities classes. Record everything; some ideas are refined later. KEY POINT: It's fine if understanding is incomplete — two more criteria get added in Elaborate. CONNECTION: SEP #2 (models) and SEP #6 (explanations) — the unit's main practices — both depend on evidence. CLASSROOM SUPPORT: Keep this as a posted chart.

TEACHER MOVE: Spectra Sequence Chart — pairs sequence cards so someone else could understand how to determine the Sun's composition. Show this slide only AFTER groups finish, as a summary. IMPLEMENTATION TIP: This may feel redundant, but it's where students literally assemble their Explore understanding; without it, the teacher ends up explaining. DIFFERENTIATION: Give only the blue (white light) cards first, then green (hydrogen), pink (other gases), yellow (Sun) — same pattern each row. LOOK & LISTEN FOR: white light contains many wavelengths we can't see separately without a prism • a spectroscopy telescope contains a prism • a gas absorbs wavelengths that depend on its composition • repeated lab trials always give the same pattern • sunlight passes through the Sun's gases • match the Sun's spectrum to lab references. ACCESS FOR ALL: Images and repeated structure support emerging and transitioning ELLs.

TEACHER MOVE: Pairs write the explanation (sentence starters in packet). Show this exemplar only after the consensus discussion, or for students who need a model. CONFERRING QUESTIONS: "Why does this finding tell us the Sun is composed of H and He?" • "I see you cited a pattern as evidence — how do you know there's a pattern? How can you make that clear?" • "Underline the sequence-chart points that best link evidence to your claim." COMMON MISCONCEPTION: Reasoning that just restates evidence ("because the lines match"). Reasoning must say WHY matching matters. DIFFERENTIATION: Scaffold = CER chart → paragraph. Extension = real spectrometer + unknown gas tubes; students cite wavelengths. CCC #1: Using patterns as evidence (MS) → needing empirical evidence for the pattern (HS).

ROUTINE — Class Consensus Discussion (first time in unit): focus on the steps. Post them in the room. TEACHER MOVE: Say: "We have a lot of different evidence-based claims circulating. It's important to agree on how we represent what we know about how the Sun works, so we have a shared understanding to build on." SELECTION: Choose 2–3 groups deliberately (NOT randomly) whose work will surface the key points. IMPLEMENTATION TIP: Project the work (doc camera, copies, or photos) — don't just read claims aloud. CONNECTION: Patterns prompts adapted from STEM Teaching Tools #41.

TEACHER MOVE: "Take Time for These Key Points" — pause and ask for clarification on each. (Fusion has not come up yet — that's next.) TEACHER MOVE: Display the Engage categories; modify the list based on the investigation. TRANSITION: The "burning" questions set up the Elaborate phase directly. SUMMARY TASK: Individually, as exit ticket or homework (next slide).

TEACHER MOVE: Students complete the Summary Task individually (exit ticket or homework). Show the answer box after collecting. OTHER SUMMARY ITEMS — expected responses: • How did you identify patterns? Compared wavelengths of dark lines across repeated samples/observations; lined up the Sun with each element. • Convince a skeptic: Point to numbers — H lines at ~410, 434, 486, 656 nm in all three lab samples AND all three Sun observations; repeats every time → pattern. DISCUSSION EXTENSION: Is a 4-point difference enough? How many students? Does the pattern tell us WHY? (No — a pattern is not a cause.) CCC #1 HS element: empirical evidence is needed to identify patterns. FORMATIVE: Collect from every student; use it to decide who needs to circle back before Elaborate.

TEACHER MOVE: Second half of the Summary Task (packet Part D). Exit ticket or homework, alongside the patterns items on the previous slide. IMPLEMENTATION TIP (from the plan): "This summary is really important!" It checks three things student by student: (1) how they are using the three dimensions to make sense of the Sun's release of energy; (2) how they and their peers are building knowledge together; (3) how they think the Class Consensus Discussion went. WHY A SLIDE: These four group-process items were previously missing from the deck entirely. COLLECT FROM EVERY STUDENT. Item 3 is also a quick read on who is — and isn't — being heard in group work.

PHASE GOAL: Students use evidence about the SCALE of energy (amount per reaction) and TIME (duration) to argue which process releases the Sun's energy. GROUPING: Pairs. TIMING: ~1 class period (argument can be finished at home). MATERIALS: Our Sun: Chemical or Nuclear Energy?, Claim and Data Cards (cut out), Constructing an Evidence-Based Argument. LAUNCH: "We know the Sun is made of hydrogen and helium, but we still don't know how they release energy." Connect to Engage ideas: burning ball of gas, explosions, chemicals.

TEACHER MOVE: Frame the two candidate processes — both involve hydrogen and connect to students' Engage ideas. ACCURACY NOTE: The packet repeats the 2.41 × 10^30 MeV/s typo here and on the Claim & Data cards. IMPLEMENTATION TIP: This value is the Sun's luminosity — don't name it yet; it's central in the next 5E.

TEACHER MOVE: Walk through the two equations from the data table. KEY POINT: Chemical reactions change how atoms are bonded; nuclear reactions change the nuclei — making new elements. ACCURACY / CONTEXT: The packet's fusion equation (deuterium + tritium → helium-4 + neutron, 17.6 MeV) is the reaction fusion reactors use. The Sun's net process (proton–proton chain) turns 4 ¹H → ⁴He and releases ~26.7 MeV. HS-ESS1-1's assessment boundary excludes these details — the scale argument is what matters. MISCONCEPTION: "The Sun is on fire." Fire = combustion, which needs oxygen.

TEACHER MOVE: Students analyze the table to find evidence for a claim about which process powers the Sun. EXPECTED RESPONSES: "Chemical would run out in 50,000 years, but Earth has had water for 4 billion years." "Fusion releases way more energy per reaction." CCC #3 — Scale, Proportion, and Quantity: the significance of a phenomenon depends on its scale. Both reactions release energy, but only fusion releases it on the scale the Sun requires. MATH NOTE: The time ratio (10 billion ÷ 50,000 = 200,000) differs from the energy ratio because the packet's values are simplified. The packet's combustion value is also lower than the textbook value (~2.5–3 eV per water molecule); either way the gap is ~10^7.

TEACHER MOVE: Use this to make the time scale concrete — 50,000 years is shorter than modern humans have existed. MISCONCEPTION: Size could make combustion last. The calculation already includes the Sun's entire hydrogen mass. This is exactly the flaw in the provided sample student argument — consider projecting it for critique. CARD NOTE: The "mass of hydrogen in the Sun is 1.813968 × 10^30" card has no units (kg). Real value ≈ 1.45 × 10^30 kg (~73% of the Sun's 1.99 × 10^30 kg). Quick "what's missing?" moment.

TEACHER MOVE: Pairs sort the cards. CONFERRING QUESTIONS: "What made you decide this card supports that claim?" • "What makes it relevant?" • "Is there evidence for both claims?" • "Which claim has more evidence?" • "What reasoning did you add?" • "How did the amounts of energy (Sun, chemical, fusion) help you decide?" EXPECT: Some students notice cards that support neither claim.

TEACHER MOVE: Debrief the sort. Reveal rows progressively as pairs share. ALSO: "We have observed energy released by fusion" → Claim 2 is possible; "…by combustion" → Claim 1 is possible. Both are real processes — the question is which fits the AMOUNT and DURATION. KEY POINT (CCC #3): Scale links the evidence (energy of the Sun vs. each reaction) to the claim that fusion occurs in the Sun.

TEACHER MOVE: Students individually write the argument (in class or at home). Lined paper for students who no longer need the organizer. EXEMPLAR (in answer key): Claim = fusion; evidence = energy scale, time scale, 4-billion-year water, helium in spectrum; critique = combustion lasts 50,000 years and needs oxygen/produces water, neither seen; limitation = we rely on calculations since we can't observe the core. SAMPLE STUDENT WORK CRITIQUE: Its Claim 1 evidence ("different reactants and products") applies to both reactions; its Claim 2 critique ("the Sun is so large") is already answered by the 50,000-year calculation. ACCESS FOR ALL: The card sort gave ELLs time with the language before writing; emerging ELLs may need verbal or home-language support.

TEACHER MOVE: After arguments are complete, ask: "Would you add anything to our criteria?" Update the poster. KEY POINT: We revised the "burning ball of gas" idea based on new evidence (energy scale) — exactly the new criterion. SEP #6: new evidence from different sources allows us to revise an explanation.

PHASE GOAL: Students revise and critique their habitability models using spectra evidence and scale of energy/time, then use the model to predict how H and He change as the Sun ages. GROUPING: Small groups of 3–4 (same as Unit Opening). ROUTINE: Idea Carousel (first use in unit); Domino Discover for DQB. TIMING: ~1 class period. MATERIALS: Groups' initial-model posters, new chart paper, sticky notes, PTO How the Sun Works, How the Sun Works Model Rubric, What will happen to our Sun in the future?, DQB.

TEACHER MOVE: Students revisit the Life in the Solar System timeline and answer independently. EXPECTED RESPONSES: Q1: The Sun has provided the right energy for liquid water for at least 4 billion years — longer than it took life to appear (~300 My after oceans), become multicellular (~3.6 By), and evolve into humans. Life needed billions of years of stable conditions. Q2: More energy → water evaporates, oceans could boil away (like Venus). Less → water freezes. Either way: no liquid water → ecosystems collapse, extinction, humans can't survive. IMPLEMENTATION TIP: These two questions create the "need to know" about the Sun's future and bridge to the next 5E.

WHY THIS SLIDE: HS-ESS1-1's clarification statement puts the emphasis on "the energy transfer mechanisms that allow energy from nuclear fusion in the sun's core to reach Earth," and PS3.D(1) reads "Nuclear fusion processes in the center of the Sun release the energy that ultimately reaches Earth as radiation." The unit plan lists as a target student idea: "The energy produced by the Sun reaches Earth in the form of electromagnetic waves which cause Earth to heat up." Students need this before they revise their models — the rubric asks for energy radiating in all directions. KEY POINT: Close the loop with Explore. Students spent two days analyzing sunlight without naming it as the energy transfer itself. Say it out loud: the light IS the energy arriving. ASSESSMENT BOUNDARY: Don't go into photon random-walk physics or sub-atomic detail. Zones are context, not content to assess. SCALE HOOK (CCC #3): Energy takes ~8 minutes to cross from the Sun's surface to Earth — but tens of thousands of years to work its way out from the core. Good contrast if students ask. TEACHER MOVE: Have students point to where each step belongs on their poster before they start revising.

ROUTINE — Idea Carousel (first use): warm feedback + suggestions on content and clarity; groups pose and respond to questions. See Unit 1 Teacher Guide. LOOK & LISTEN FOR: Our Sun is a star that has provided the right energy for liquid water for billions of years • life has been sustained over that time • stable energy made Earth a place where species can survive • we can establish Earth's history using evidence from various devices. FACILITATION: If some ideas surfaced in only some groups, have those groups share; not every group needs to share. ACCESS FOR ALL: Ideal for emerging ELLs — students with receptive language can engage by listening and annotating. Then groups revise using the feedback.

TEACHER MOVE: Students independently refine their model in the PTO (How the Sun Works: reflection prompts, Change/Evidence/Reasoning table, drawing). Show this slide as a checklist after a first draft. RUBRIC (Proficient): H & He as particles • fusion in the core • energy radiating in all directions incl. toward Earth • components speak for themselves or are captioned • empirical evidence cited for patterns • scale of energy AND scale of time addressed. RUBRIC NOTE: Rubric "reflection prompt 1" = PTO prompt 1; rubric "reflection prompt 2" = PTO prompt 4. RUBRIC USES: self-assessment; class critique of a fictional composite model; teacher scoring vs. self-scores; partner review — then revise. RELEVANCE PROMPTS: Consider a whole-class share and displaying responses.

TEACHER MOVE: These are the PTO reflection prompts for How the Sun Works. Students respond BEFORE revising the drawing, then cite evidence and reasoning for any change they make. EXPECTED RESPONSES: 1. Dark absorption lines in sunlight line up with hydrogen and helium lines; the same pattern repeats across every observation and every lab sample. 2. The model should now show a MECHANISM instead of an arrow labeled "heat": H nuclei fusing into He in the core, releasing energy that travels outward and reaches Earth as radiation. 3. The Sun has released energy at a nearly steady rate for ~4.6 billion years with enough hydrogen for billions more. No chemical process could do that for that long. Comparing the scale of the energy to the scale of the time is what rules out burning. 4. Open response. Look for: a process can look completely different depending on the size or time span you examine it over — plate motion, erosion, climate change, population growth. FORMATIVE: Prompt 2 is the one that shows whether a student has moved from description to mechanism.

TEACHER MOVE: Pairs make predictions. Let students struggle before giving the conferring prompts (examine the equation; fusion is irreversible). EXPECTED RESPONSES: 1. Hydrogen DECREASES — it's the reactant, used up in every reaction. 2. Helium INCREASES — it's the product and accumulates. 3. NO — hydrogen fuel is limited; the Sun will eventually run low and change. LOOK & LISTEN FOR: "The Sun will run out of hydrogen and stop releasing energy." • "The Sun will explode." • "Maybe helium will fuse into heavier elements." MISCONCEPTION: "The Sun will explode" — the Sun isn't massive enough to go supernova; it will become a red giant, then a white dwarf. Don't resolve now — it motivates Star Life Cycles (HS-ESS1-3). SUBJECT CONTEXT: The Sun slowly brightens (~10% per billion years) — Earth may lose its oceans in ~1 billion years, long before the Sun "runs out." SEP #2 HS element: using a model to make predictions.

TEACHER MOVE: Summarize predictions from the pair share. KEY POINT: "Burn out" in the DCI is figurative — no combustion is involved. Worth saying explicitly after the Elaborate phase. TRANSITION: Revisit the Driving Question Board.

TEACHER MOVE: Domino Discover — pairs share what they've figured out and what they still need to investigate. Prompt new questions about finding another star that could support an Earth-like planet. TRANSITION SCRIPT: "I'm noticing a lot of questions about how long other stars last and whether they provide the right energy for liquid water, so next we will investigate these questions." (Next 5E: Star Life Cycles.)

TEACHER MOVE: Reference slide for study/review. Per the plan's Access for All note, vocabulary is learned in context — use these as a reference, not a list to memorize up front.

TEACHER MOVE: Reference slide. CCC #3 — "scale" is the lens that ruled out combustion. UP NEXT: Luminosity (the Sun's energy output per second) becomes central in the Star Life Cycles 5E.