the earth revolves around the sun once per year (imagine a circle around
the sun). the earth also rotates on it's axis (the Poles) once per day.
[fast] But this axis is not perpendicular to the 'circle' of earth's
orbit around the sun. so...

visualize that the circular around the sun is "horizontal". lets choose
our vantage along this circle so that the earth's axis is now tilted at
one extreme when we see the earth at the leftmost position on this
circle. And lets say that teh north pole is tilted toward the sun.
(therefore teh south pole is tilted away from teh sun)

visualize those fast daily revolutoins. notice that teh top of the earth
(north) is predominantly exposed to sunlight. It's summer. :-)

eventaully, 6 months later, the earth is on the oppostie side of it's
orbit (but it's axis ALWAYS remains tilted exactly same angle) So now
the south pole sees a lot of sunlight. and so, it's winter



the equator.
visualize your self at one dot on the equator. say you're on the
nightitnme side of earth. as earth rotates to give you dawn, you swing
around and i think you see the sun from your south. you should see it
from the south all day.

6 mo later you should see the sun from the north (all day)