1. http://esminfo.prenhall.com/science/geoanimations/animations/01_EarthSun_E2.swf
2. http://www.ictgames.com/dayNight/index.html
3. http://www.harcourtschool.com/activity/science_up_close/317/deploy/interface.swf
4. http://www.childrensuniversity.manchester.ac.uk/media/services/thechildrensuniversityofmanchester/flash/earthandbeyond_a.swf
5. http://www.turtlediary.com/science-games/solar-system.html