Planet orbit radius, period,speed, Make a model of a solar system and measure the speeds of the planets.
Gravity Well, observe a model of how planets move.
Rectified Globe Use an earthglobe placed in sunlight to see the illumination of the earth.
Sun Angle Analyzer
Seasons explore planets with different tilts and elliptical orbits.
Gems The Real Reason for the Seasons
Source for Liquid Crystal Sheets, Edmunds
This page is available here http://www.exo.net/~pauld/workshops/PLanets/planetsOrbitsSeasons.html
Scientific Explorations by Paul Doherty
20 May 2015