Movements of the Earth

3 basic motions of Earth Rotation: Earth’s rotation is the rotation of the solid Earth around its own axis. The earth rotates towards the East.

3 basic motions of Earth Revolution: The earth’s movement “orbit” around the Sun. Earth travels around the Sun once every 365 ¼ days.

3 basic motions of Earth Precession: the movement of the rotational axis of a body Earth’s will complete one circuit in approximately 25,700 years

Reasons for the Seasons

This is Saturday…9/22

Reasons for the Seasons Earth’s Axis tilt: Winter = Away Spring = Neither Summer = Towards Fall = Neither

Earth’s Orbit Aphelion -- the point on its orbit when the Earth is farthest from the sun 152,097,701 km (1.01 AU) Perihelion -- the point on its orbit when the Earth is closest to the sun 147,098,074 km (0.98 AU)

Earth’s Axis Tilt and Sun Angle

Sun Angle and INTENSITY

Intensity and Earth’s Seasons

CLASSWORK/HOMEWORK Do objective’s 2.05 – 2.09 See book (p. 591-593) for all answers.

Science Tip of the Day September 23, 2010 Fall officially started this morning at 3am. What did we “officially” call this? Earth’s tilt (23.5o) causes seasons. Explain (use your obj. notes) why. - Include: Tilt, Sun Angle & Intensity 3. Did you ask your family why it’s warm in summer and cold in winter? What’d they say?

EQUINOX September 23 How does the sun appear anywhere on the globe today?

Solar System Unit of Measurement The astronomical unit (AU ) is a unit of length based on the distance from the Earth to the Sun. 1 Astronomical Unit = 149 598 000 kilometers (93 million miles).