A not-all-together sane way of showing a class how retrograde motion works!


Here's how to show your students why stars twinkle in the night sky!

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The geometry behind moon phases.

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Read more: Phases of the Moon

Using a laser and some boiling water,

you can show why planets do not appear to twinkle in the night sky. 

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Eclipses occur as a result of the geometry between the Earth, Moon, and Sun.

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Read more: Why Do Eclipses Happen?