1. Earths Motions Objectives:
To describe the motions of the earth in terms of rotation and revolution.
To understand the apparent motions of celestial objects as they relate to the earth.

2. TOPIC 4 EARTH’S MOTIONS ROTATION- ROTATIONAL VELOCITY- rate of spin,
EVIDENCE OF ROTATION
FOUCAULT PENDULUM-
CORIOLIS EFFECT-
Northern hemisphere-
Southern hemisphere-
SEE REFERENCE TABLE PG. 4- OCEAN CURRENTS
PG 14- WIND PATTERNS

3. Focault Pendulum-evidence of rotation
Earth rotation
See movie
Coriolis effect
See movie

4. Fast Facts
At the North Pole (90 degrees north) and South Pole (90 degrees south), the speed is effectively zero since that spot rotates once in 24 hours, a very, very slow speed.
For other latitudes...10° mph ( km/h)
20° mph ( km/h)
30° mph ( km/h)
40° mph ( km/h)
50° mph ( km/h)
60° mph (834.9 km/h)
70° mph (571.1 km/h)
80° mph ( km/h)
In addition to the rotational speed of the earth spinning on its axis, the earth is also speeding at about 66,660 miles per hour ( km/h) in its revolution around the sun once ever days.

5. Turn and Talk to your neighbor.
Answer the following questions.
What direction does the earth rotate?
How fast does the earth rotate?
What are 2 evidences of the earths rotation?
Which way do ocean currents and wind patterns deflect in the Northern Hemisphere?

6. REVOLUTION Earths revolution around the sun is –
EARTHS ROTATION CAUSES:
The sun, moon, planets and stars to appear to –
The apparent diameter (size) of the planets, sun and moon is –
In the summer the sun appears smaller because we are -.
Apparent diameter of stars will remain constant, -
REVOLUTION
Earths revolution around the sun is –
The eccentric orbit causes the apparent diameter of the sun to -.
The moon’s revolution around the earth, causes -

7. Revolution of moon around earth -
The revolution of earth around the sun-

9. Turn and talk Answer the questions.
1. What does the revolution of the earth around the sun cause?
2. What does the revolution of the earth around the moon cause?

10. Geocentric Model-Earth Centered
Earth is stationary
All objects revolve around earth in perfect circles
Too complex-could not explain some motions of celestial objects
Heliocentric Model-Sun Centered
Earth rotates and revolves
Slightly elliptical orbits
Easier model, less complex
Could explain terrestrial motions (rotation, revolution) and motions of planets- retrograde motion
Could not explain motions of outer planets- retrograde motion

11. Turn and Talk:
Describe the differences between the helio and geocentric models.
Use diagrams to illustrate your findings.
Why was the geocentric model replaced with the heliocentric model?