The Earth is a sphere. It can be divided into two
hemispheres, the Northern and Southern Hemispheres.
The best way to understand this is to make a model. You
will need an orange, or any other spherical object that you can pierce, a marker
and a knitting needle skewer or sharp, thin stick.
Take the needle, stick or skewer and pass it right
through the center of the orange, from top to bottom. Where it enters the orange
at the top is the North Pole, and where it comes out at the bottom is the South
Use the marker to draw a line around the middle of the
orange, dividing it into a top and bottom half. The line represents the Equator,
the top half is the Northern Hemisphere, and the bottom half is the Southern
Now your orange should look like this:
The stick represents the Earths axis. The axis is an
imaginary line running from the North to South poles. The Earth spins on this
axis all the time, turning around completely once every 24 hours. Take your
orange, hold it by both ends of your stick, and turn the stick between your
fingers. Notice how the orange turns around. That is what gives us night and
day. However, it has nothing to do with the seasons, winter, spring, summer and fall. So far we have only shown
that the earth has night and day. So what makes the seasons happen?
At the moment you are holding your orange with the stick
going straight up and down. That isnt how it works. The whole Earth is
actually tilted. Hold the orange in one hand and tip it, so that the top of the
stick is nearer you than the bottom. Dont tip it too far we dont want
the stick pointing straight at you, about half way between upright (vertical)
and flat (horizontal) will do nicely.
THAT is how the Earth is in space.
Now it should look like this:
Notice how the top half, or Northern Hemisphere, is
tipped toward you, with more of it showing than the Southern Hemisphere.
The effects of Direct and Indirect Sunlight
What Causes the Seasons?