http://www.ncsu.edu/scivis/lessons/earthinspace3d/earth2.html

http://www.lpi.usra.edu/education/other_programs/lunar_eclipse/fruit_loops.shtml

http://classroom.jc-schools.net/sci-units/earth.htm

http://usln.fi.edu/time/Journey/JustInTime/seasons2.html

http://www.crh.noaa.gov/fsd/astro/season.htm

http://www.ndbc.noaa.gov/educate/seasons_ans.shtml

http://www.erin.utoronto.ca/~astro/lesson4.htm

http://sched.sbu.edu/FACULTY/ncasey/HTMLFiles/earthsunmoon/earthsunmoon-RH.html

http://ksnn.larc.nasa.gov/k2/s_nightDay_a.html

http://www.24hours7days.com/Astro/Investing_Astronomy_Kits.html