Kepler

Kepler’s laws describe planetary motion. His work is part of the shift from geocentric to heliocentric models of the solar system. You are expected to know evidence for them (retrograde motion etc.)

http://www.physicsclassroom.com/class/circles/Lesson-4/Kepler-s-Three-Laws
http://csep10.phys.utk.edu/astr161/lect/history/kepler.html
http://m.youtube.com/watch?v=4p3Np6eivZ8
http://m.youtube.com/watch?v=GcKiG-CuvtA

It also builds towards the work we will be doing on gravitation. To get you thinking: http://m.youtube.com/watch?v=MTY1Kje0yLg.