# the imaginary line that goes through the center of the Earth.

October 5, 2012 - It’s Friday 
WARM-Up
(remember to date and write in
WHY DO WE HAVE DAY
AND NIGHT???
Tests, Quizzes, etc are being returned.
1 The reason we have day and night is because
the Earth rotates.
2 Rotate means
to turn.
The Earth rotating on its
axis
gives us day and night.
3 Earth’s axis is
the imaginary line that goes through the
center of the Earth.
This spinning
around like a
top is called
rotation. As it
spins only one
side faces the
sun. Day
begins when
our part of the
world turns to
face the sun.
Night falls when our part of the Earth
turns away from the sun. The side
facing away from the sun has
nighttime.
DAY AND NIGHT
4 This rotation or spinning of
Earth causes day and night.
The Earth rotates on its axis.
The axis is an imaginary line
through its center. It rotates
once every 24 hours causing
day and night.
But guess what! Rotating isn’t the only
way the Earth moves in space!
5 The Earth also revolves.
Revolve – When one object moves around
another object
True or False?
The Earth has seasons because…?
• The Earth moves closer to or farther from the
Sun - it’s closer in the summer and farther in
the winter.
False!
6 The Earth has seasons because its
axis is tilted 23.5&ordm; and its revolves
around the Sun.
Have you ever notice how globes are
always tilted?
7 One revolution around the sun equals 365.25
days.
What about the word orbit?
8 Orbit The path that an
object follows as it
revolves around
another object.
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 ________.
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.