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Grade 8 · unit review

Review: Earth, Moon and Sun Geometry

Explain phases, eclipses and seasons with distinct models.

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Bring the unit skills together

Use these 4 new cases to check your reasoning. Choices are temporary and are not saved to an account, sent to staff or recorded as school grades. Download your current review choices before leaving or reloading.

Unit review questions
1. Which scientific label fits the specifically described step or feature? Supplied case: Moon appears half illuminated.
Need a hint?
  • Look for the described feature: about half the visible disk is lit.
  • Compare the given mechanism with the other labels; do not infer unmentioned events.
2. Which scientific label fits the specifically described step or feature? Supplied case: Earth’s shadow falls on Moon.
Need a hint?
  • Look for the described feature: Moon enters Earth’s shadow.
  • Compare the given mechanism with the other labels; do not infer unmentioned events.
3. Which scientific label fits the specifically described step or feature? Supplied case: Daylight duration rises in the tilted-toward hemisphere.
Need a hint?
  • Look for the described feature: hemisphere tilted toward Sun has more direct light.
  • Compare the given mechanism with the other labels; do not infer unmentioned events.
4. Supplied case 5: model period (days)=40; cycle fraction=0.5, using the explicitly named quantities. Elapsed model days equal period in days multiplied by cycle fraction. What result follows?
Need a hint?
  • Elapsed model days equal period in days multiplied by cycle fraction.
  • A fraction of a cycle is not a new astronomical constant.

The download contains your current choices and any checked feedback. Keep the separate transfer-task work in your own document; downloading its instructions does not mark it complete.

Use the skills in a new task

Create a four-panel explanation for “Earth, Moon and Sun Geometry” using one supplied case from each lesson. Include the observation, scientific mechanism or calculation, result and a limitation. You may draw and speak your explanation; all inputs are supplied.

Work on paper or in your own document. Explain the choices you made.

  • Use one supplied case from each of the four lessons.
  • Name the relevant structure, quantity or process in every panel.
  • Show calculations with units or a causal evidence chain.
  • Distinguish source facts from fictional classroom data.
  • State a model limit or a condition that would change the result.
Compare with a model response

Panel 1: A quarter-phase Moon is visible while Earth’s shadow misses it. Which explanation fits? Which inference or prediction is best supported? Result: The viewing angle shows half of the apparent disk illuminated; no Earth shadow is needed.. Reasoning: Ordinary phase is a view of the Moon’s generally half-lit sphere, not shadow coverage by Earth. Model limitation: only the stated classroom boundary and supplied observations are established; unmeasured real-world performance remains unverified. Panel 2: At new phase the Moon lies above the exact Sun-Earth line. What follows? Which inference or prediction is best supported? Result: A solar eclipse is not guaranteed because the shadow may miss Earth.. Reasoning: Orbital tilt and alignment matter beyond phase; the shadow must reach the observer’s region. Model limitation: only the stated classroom boundary and supplied observations are established; unmeasured real-world performance remains unverified. Panel 3: North tilts toward the Sun while south tilts away at the same Earth-Sun distance. What fits? Which inference or prediction is best supported? Result: North can have longer days and more direct light while south has the opposite.. Reasoning: Tilt changes daylight geometry and sunlight angle without requiring different hemispheric orbital distances. Model limitation: only the stated classroom boundary and supplied observations are established; unmeasured real-world performance remains unverified. Panel 4: Supplied case 1: model period (days)=28; cycle fraction=0.25, using the explicitly named quantities. Elapsed model days equal period in days multiplied by cycle fraction. What result follows? Result: 7 days. Reasoning: Substitute the supplied values: (28)*(0.25) = 7 days. Use the supplied simplified period. Real phase timings need observation and orbital detail. Model limitation: only the stated classroom boundary and supplied observations are established; unmeasured real-world performance remains unverified.

A different response can also meet the criteria. Compare the evidence and reasoning, rather than copying the wording.