NASA
National Aeronautics and Space Administration: Scijinks: Seasons
An explanation about the rotation of the Earth and why the Earth has seasons.
Other
Nasa: Iss Earth Kam
Students get a whole new perspective of the world through images obtained from the International Space Station. Students can even request images to be taken through ISS EarthKAM. Activities and educator guides are provided.
NASA
Nasa: Image Science Center: Ask the Space Scientist Earth
Site from NASA contains a collection of 91 questions pertaining to the Earth's atmosphere, magnetic field, ionosphere, rotation and origin of life.
NASA
Nasa: The Sun
An introduction to the Sun including its size and distance from the Earth, sunspots, flares and coronal mass ejections.