1. Bell Ringer Describe the difference between the geocentric model of the solar system and the heliocentric model of the solar system

2. Rotation, Revolution and Star/Sun Paths

3. Celestial Sphere All celestial (sky) objects appear to be on a sphere that encircles Earth.

4. Celestial Sphere The horizon is where the sphere meets Earth in the distance. This is also where the sun rises and sets.

5. Rotation and Revolution 1.Rotation is the turning of an object on its axis. Tilted at an angle of 23.5° Rotates counterclockwise (west to east) at a rate of 15°/hr

6. Rotation and Revolution 2.Revolution is the movement of one object around another in a set path (orbit). shape of the orbit is an ellipse

7. Revolution and Rotation around the sun

8. Star Paths All objects including stars appear to move from east to west along an arc (portion of circle’s path) Objects appear to move 15 degrees per hour through the sky

9. Star Paths At the poles, the stars don’t rise or set- instead they circle the pole. These stars are known as circumpolar stars. Circumpolar Timelapse Video

10. Sun’s Path The Sun rises in the east and sets in the west, moving through the southern sky. At our latitude the Sun is also never directly overhead.

11. Sun’s Path The Sun is highest in the sky at noon. The Sun’s arc is lowest in winter and highest in summer.

12. Sun’s Path The apparent motion of the Sun through the sky is due to Earth’s rotation.