Science U
Science U: Reasons for the Seasons
This webpage uses diagrams and video to explain the causes of the seasons.
Science Buddies
Science Buddies: A Matter of Degrees: Tilt of Earth's Axis Affects the Seasons
In this science fair project, use a globe and a heat lamp to investigate how the angle of the Sun affects global warming. This project includes the objective, background questions, a list of all the materials you'll need, and the...
Other
Lunar and Planetary Institute: Sky Tellers: Myths, Magic, Mysteries of Universe
Very nice website with excellent graphics depicting the change of the seasons and how the seasons are different between the northern and southern hemisphere. Also has a nice informational table of the spring and fall equinox and summer...