Eighth Grade · Science · week 35

Scale-model capstone

Apply the scale ratios from week 32 to plan and describe building a physical scale model of the Earth-Moon-Sun system with one consistent scale factor.

This week applies the scale-modeling math from earlier to a real, planned project. The process stays the same no matter what represents the Sun: pick an object, measure or look up its diameter, and apply the same two ratios from before to find every other size and distance.

Earth's diameter is about 1/110th of the Sun's, and the Earth-Sun distance is about 107 times the Sun's diameter. Whatever object represents the Sun, dividing its size by 110 gives Earth's modeled size, and multiplying by 107 gives the modeled Earth-Sun distance.

📋 For the teacher
Teach it (10–15 min):
  • Let them choose the "Sun" object themselves and do the two calculations (divide by 110, multiply by 107) with your help checking the arithmetic.
  • Go measure out the calculated distance somewhere nearby if at all possible -- walking the real modeled distance is the most memorable part of this unit.
  • Revisit why one scale factor for the whole model, not a separate size scale and distance scale, is what makes it a true scale model.
Talk about it:
  • What two calculations do you need for any object you choose to represent the Sun?
  • What surprised you about measuring out your model's Earth-Sun distance in a real space?

Mastery looks like: They calculate a scaled Earth size and Earth-Sun distance for a chosen "Sun" object, applying the same scale factor consistently.

Common stumbles: Using a different scale for size than for distance; skipping the step of confirming the chosen "Sun" object's real diameter.

Homework for this lessonType it, write it with a stylus, or print it for pencil & paper.open →
Records attendance + 15 min of Science for this learner.
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