Transcript The Earth in Motion

Do Now…
1.
One looseleaf…
a.
b.
c.
d.
2.
# of hours in a day ____________
# of days in a month ___________
# of days in a year ____________
# of months in a year __________
Why do we experience Day/night?
Aim: Why does the Earth have
day and night?
Earth from Space…
what do you see?
http://www.youtube.com/watch?v=knK87G
oNyGo&feature=related
Earth’s Motions:
1. Axis
a. Imaginary line that
passes from the north to
south pole around which
the Earth spins.
b. Earth is tilted on its axis
at 23.5 degrees
c. The North Pole points to
Polaris…the North Star.
Finding the North Star
Earth’s Motions:
2. Rotation
a. The spinning of a planet about its axis.
1 rotation = 1 day = 24 hours.
b. The Earth rotates because of inertia- Once it was set in
motion, it stays in motion
c. ½ the Earth is always in light and ½ is always in darkness
Day and Night
What evidence tells us that the
Earth rotates?
1.Sunset
2.Sunrise
3. Moon rises and sets
4. Shadows change during the day
5. Star trails – stars appear to move in the sky
More Star Trails
6. Foucault’s pendulum
3. What direction does
the Earth rotate?

Rotating Earth
a. Counterclockwise (from west to east)
b. *The sun rises in the east and sets in the
west.
Draw a picture of Sunrise/Sunset…
Do Now:
In which direction would you look to see the
sun rise?
In which direction would you look to see the
sun set?
4. What is the shape of the Earth?
a. The Earth is an almost
perfect sphere.
b. Rapid spinning causes the
middle to bulge
and the poles to flatten.
c. The diameter of the Earth is
29 miles wider at the equator
than at the poles!


The diameter from Pole to Pole
= 12,714 km
The equatorial diameter =
12,756 km.
How fast does the Earth rotate?
a. There are 360 degrees in a sphere
b. There are 24 hours in one day.
That’s 1,038 miles per hour!
Calculate
how many
/ hour the
Why don’t
wedegrees
fly off???
earth rotates:
360 degrees =
24 hours
15 degrees/hour
The Earth at Night…
what’s wrong with this picture?
What causes the seasons?
5. Earth’s Revolution
a. Earth moves around the sun
b. It takes about 365 ¼ days for Earth to
make one full revolution.
c. Causes Earth’s seasons
Why do daylight hours change
during the year?
Earth’s position around the sun causes the
sun to be higher or lower in the sky.
a. Summer – sun rises higher, takes longer to
set, longer daylight hours, shorter shadows
b. Winter – sun rises lower, takes less time to
set, shorter daylight hours, longer shadows
Earth
Revolution
Animation
Bird’s
Eye
View
Too!