What Causes Seasons?
We know that the reason we have day and night is
because the Earth rotates.
Rotate means
to turn.
The Earth rotating on its
______
axis
gives us day and night.
Earth’s axis is
the imaginary line that goes through the
center of the Earth.
But guess what! Rotating isn’t the only way the
Earth moves in space!
The Earth also revolves.
Revolve – When one object moves around another
object
How long does one revolution take?
It takes the Earth one year, or 365 ¼
days to orbit the sun.
Does anyone know
what orbit means?
Orbit -
The path that an object
follows as it revolves around
another object.
All over the world, people experience the four
seasons.
Winter…
Spring…
Summer…
and fall.
But why do we have four seasons?
It’s because the Earth’s
axis is tilted.
Take a good look at
our globe. It‘s not tilted
like that because it
looks nice. No way.
That’s the way the
Earth is tilted in space.
That tilt gives us seasons!
Look at this diagram. Notice how the Earth is
always tilted in the same direction. As the
revolves the part of Earth tilted
Earth __________
toward the sun changes.
During part of the year the North Pole tilts
summer
towards the sun. This season is ________.
During another part of the year, the North Pole
winter
points away from the sun. This season is ______.
When the North Pole is
tilted toward the Sun, the
Sun travels higher
overhead in the sky. The
Sun’s rays shine
straighter down on that
part of the Earth. It is
summer in that part of the
Earth.
It’s like pointing a
flashlight at a piece
of paper. When you
hold the flashlight
straight above the
paper, the rays from
the flashlight shine
down straighter.
When the North Pole is
tilted away from the Sun,
the Sun stays lower in the
sky. It is then winter in
that part of the Earth.
If you point your flashlight
at a piece of paper at an
angle, the rays from the
flashlight spread out.