Lesson 3: Solar and Lunar Eclipses

What geometric conditions must occur for a solar eclipse versus a lunar eclipse?
Why do eclipses NOT occur every month during new and full Moon phases?
How does orbital tilt affect whether alignment produces an eclipse?
What determines whether an eclipse is total, partial, or annular?
Why are eclipses only visible from specific regions on Earth?
How can shadow geometry be used to predict eclipse visibility and type?

Solar eclipse
Lunar eclipse
Umbra
Penumbra
Total eclipse
Partial eclipse
Annular eclipse
Syzygy (alignment)
Orbit
Node
Ecliptic plane
Shadow cone
Path of totality
Orbital inclination

HS-ESS1-2
Analyze and interpret data to explain how the Moon’s orbit and Earth–Moon–Sun alignment produce observable phenomena such as solar and lunar eclipses
HS-PS2-4
Use mathematical and conceptual models of gravitational interaction to explain orbital motion, alignment conditions, and shadow formation in the Sun–Earth–Moon system
NGSS Crosscutting Concepts
Patterns
Cause and Effect
Systems and System Models
Scale, Proportion, and Quantity

Interpret orbital alignment diagrams to determine eclipse type and occurrence
Analyze eclipse path maps to explain why visibility is location-specific
Apply spatial reasoning to determine umbra and penumbra regions
Construct evidence-based explanations using eclipse geometry and data

Students will investigate how eclipses occur only when precise orbital alignment intersects with the Moon’s orbital nodes
Students will analyze how shadow geometry determines eclipse type and visibility
Students will evaluate real eclipse path data to connect models with observational evidence
Activities may include:
Modeling solar and lunar eclipses using lamps, globes, and spheres
Identifying umbra and penumbra regions in shadow simulations
Testing alignment scenarios using digital eclipse simulators
Analyzing NASA eclipse maps and path-of-totality data
Comparing conditions required for solar vs. lunar eclipses
Purpose
Strengthen students’ ability to apply spatial reasoning and orbital geometry to rare celestial events
Develop predictive reasoning using alignment models and real-world astronomical data
DOK Level
3–4 – Strategic Thinking to Extended Reasoning
(modeling, spatial analysis, prediction, and justification using evidence)

Connects eclipses to historical interpretations and cultural responses across civilizations
Examines how eclipses have been used to validate scientific theories (e.g., testing models of celestial motion)
Relates modern eclipse prediction to NASA missions and citizen science observation programs

Students may believe eclipses occur during every new or full Moon
Students may think eclipses are visible from the entire Earth simultaneously
Students may believe the Moon disappears completely during a solar eclipse
Students may confuse which object casts the shadow in each eclipse type
Students may assume orbital alignment is perfectly consistent each month

Step-by-step guided eclipse alignment modeling
Visual distinction between umbra and penumbra regions
Comparative graphic organizers (solar vs. lunar eclipse)
Interactive simulation-based prediction tasks
Structured alignment reasoning frameworks
Partner explanation and peer-justification activities
Scaffolded spatial reasoning support for orbital tilt concepts

• Formative assessment during eclipse modeling activities
• Vocabulary quizzes focused on alignment and shadow terms
• Diagram labeling assessments (eclipse type + shadow regions)
• CER written explanations of eclipse formation
• Exit tickets predicting eclipse occurrence from alignment scenarios
• Analysis of real eclipse maps and path-of-totality data

• Lamps, spheres, and globes for eclipse modeling
• Solar and lunar eclipse diagrams
• Digital eclipse simulation tools
• NASA eclipse path maps and datasets
• Umbra/penumbra visualization worksheets

• Historical eclipse imagery and case studies