1. Aim: How is the Earth moving?
Notepack 27
Aim: How is the Earth moving?
Do Now: Are you sure the Earth is Rotating? How do you know?

2. The Tilt of the Earth The Earth is tilted on its axis 23.5°.
23.5 = a magic Earth Science number.
Polaris is always above the north pole.

3. How do we know The Earth is rotating (spinning)?
Star trails – stars move across the sky at night. Polaris (north star) is above the Earth’s axis so it does not appear to move.
Polaris

4. A Star Swirl on Film
Here is a photo of the night sky with the shutter left open.
The stars appear to move in circular arcs.
The North Star is the star in the center.

5. Star Trails https://www.youtube.com/watch?v=xzrQS7bGUkc

6. Altitude of Polaris
Altitude of Polaris = how high Polaris is in the sky
Altitude of Polaris
=your latitude
(in northern hemisphere)

7. Can you find polaris?

8. How do we know The Earth is rotation (spinning)?
Foucault pendulum
A pendulum is any weight that swings back and forth on a string.
A scientist names Foucault noticed that the pendulum switched direction every hour.
Over a 24 hour period, the pendulum made it completely around to its original swinging position.

9. Foucault Pendulum

10. How do we know The Earth is rotating (spinning)?
Coriolis force :
Winds may move north or south due to changes in air pressure.
Due to the Earth’s rotation, the winds will not travel in a straight line, but rather curve.
Watch the demonstration and video.

11. Coriolis Force http://www.youtube.com/watch?v=mcPs_OdQOYU

12. WHAT ELSE IS EARTH DOING?

13. How do we know that the Earth is Revolving around the Sun?
We know that the Earth is revolving around the Sun because the constellations appear and disappear throughout the year.
This is possible because the Sun is at the center of the solar system.
Since we can only see constellations at night, and the daytime side of the Earth is always pointing towards the center of the solar system, the night sky is always facing a new part of the sky each night.

15. Earth is revolving around the sun.
What is the shape of its orbit?

16. Exit Slip
What is the altitude of Polaris (in degrees) for someone who lives at 45° N latitude?
Describe one way we know Earth is rotating. (2 or more sentences)