Lesson 1 — Engage

Where did everything come from?

Has the universe always been the same?

• Task:
  • Write an initial claim: How did the universe form and lead to stars and planets?
  • Choose your best idea and put it on your mini whiteboard.

Rumors Routine

• Move around and share your claim
• Listen for similarities/differences
• Norms:
  • Honor all ideas; we will examine scientific evidence next
  • Focus on testable, scientific claims in upcoming lessons

Video: How Many Stars?

• What surprised you?
• What does “many stars → many planets” suggest?

Why study origin?

• Scientists compare galaxies/solar systems by understanding how the universe formed
• We’ll use evidence to build a scientific model (compatible with many beliefs, focused on testable claims)

Lesson 2 — Explore

Investigating light from other galaxies

• Phenomenon:
  • Galaxy absorption lines match H/He patterns but are shifted to red
• Question:
  • Why are lines more redshifted for more distant galaxies?

Models We’ll Use

• Model 1: Doppler (sound, moving source)
• Model 2: Piano (pitch frequency/wavelength)
• Model 3: Galaxy redshift (light + motion)
• Model 4: EM spectrum (frequency color)

See–Think–Wonder (Group)

• See:
  • Toward observer → waves bunch → higher frequency
  • Away from observer → waves spread → lower frequency
• Think:
  • Sound behavior helps explain light behavior
• Wonder:
  • How does motion change perceived color?

Key Observations

• Sound: Higher pitch = higher frequency = shorter wavelength
• Light:
  • Moving away → lower frequency, longer wavelength → redder
  • Moving toward → higher frequency, shorter wavelength → bluer
• Distant galaxies show increasing redshift with distance

Lesson 3 — Explain

Explaining redshift

• Claim to test:
  • If spectra redshift increases with distance, the universe is expanding

Construct Your Explanation

• Use wave-model evidence:
  • H/He absorption signatures shift red
  • Redshift magnitude increases with distance
• Link:
  • Expansion → galaxies recede → light stretches → redshift

Class Consensus Discussion

• Steps:
  1. Selected groups present claims + reasoning
  2. Peers restate + ask clarifying questions
  3. Table confers → whole-class agreement
• Focus prompts:
  • How did models serve as evidence?
  • Was energy destroyed or transformed?
  • What are model limitations?

Take Time for These Key Points

• H/He absorption patterns shift red with distance
• Longer wavelengths (red) indicate motion away
• Therefore, the universe is expanding

Summary Task (Exit Ticket)

• Write a short paragraph:
  • Your explanation for redshift
  • Evidence (models + spectra)
  • One limitation or lingering question

Lesson 4 — Elaborate

If the universe is expanding, what was it like before?

• Guiding Question:
  • If expanding now, what was it like 13+ billion years ago?

Balloon Model Activity

• Inflate = expansion
• Inferences:
  • Earlier universe: smaller, denser, hotter
  • Galaxies closer in the past; at the beginning → clumped

Conservation Principles

• Energy isn’t created/destroyed; it moves/changes
• Matter isn’t created/destroyed; it moves/changes
• Implication:
  • Early H, He, and energy should persist today (possibly transformed)

Test the Big Bang Claim

• Predict present-day evidence:
  • Cosmic Microwave Background (CMB): cooled, stretched radiation
  • H/He ratios: ~3/4 H and ~1/4 He (primordial nucleosynthesis)
  • Light stretching: visible light shifts to longer wavelengths over time
• Compare predictions to observations

Read + Analyze

• Read short text on early universe temperature/pressure
• Watch: Origins of the Universe (0:00–1:10)
• Pair work:
  • Make 3–4 testable predictions
  • Match with observed data (CMB maps, elemental abundances)

Consensus (Evidence)

• Prompts:
  • How did conservation help link evidence to claims?
  • Which evidence most strongly supports Big Bang?
• Key points:
  • H:He ratio aligns with early-universe formation
  • Stretched waves explain microwave background
  • Evidence supports a small, hot, dense early universe

Lesson 5 — Evaluate

Is life elsewhere probable?

• Use your origin/formation model:
  • Big universe → many stars → many planets
  • Similar formation processes → similar features across galaxies

Model Earth-like Planets

• Pair activity:
  • Build a formation/solar system model
  • Consider habitability (star type, orbit, atmosphere, time)
• Questions:
  • How many opportunities for life?
  • What increases/decreases probability?

Idea Carousel (Peer Critique)

• Annotate peers’ models with:
  • Resonates
  • • Add
  • ? Question relevance
  • Δ Clarify/represent more clearly
• Revise your model using feedback

Revisiting the Performance Task

• Individually:
  • Claim: Probability of life elsewhere
  • Evidence:
    • Expansion + scale (stars/planets)
    • Formation processes across galaxies
    • CMB + H/He ratios supporting origin model
  • Address counterpoints/uncertainties

Driving Question Board (Closure)

• Which questions did we answer?
• What’s next?
  • Stability of the solar system
  • Extinction and contact: Could intelligent life be rare or short-lived?

Check Your Understanding

• Why does redshift increase with distance?
• What does the CMB tell us?
• Why is the H/He ratio important?
• How do conservation laws connect past to present?
• What evidence supports the claim that life elsewhere is probable?

End of Unit — Key Takeaways

• Universe is expanding (redshift evidence)
• Early universe was small, hot, dense (CMB + abundances)
• Big Bang explains present-day observations
• Similar formation pathways suggest many Earth-like planets may exist