Earthseasons.gif

The tilt of the Earth causes the seasons.
As the Earth orbits the Sun,
the tilt of the Earth's axis does not change.
The Earth always leans in the same direction.


http://www.windows2universe.org/earth/climate/cli_seasons.html

See an animation of Earth revolving around the sun!
http://www.learner.org/jnorth/tm/ReasonsBack.html