1. The Earth-Moon-Sun System (chapter 7)

2. Points of note…. Earth is a sphere. Gravity causes large objects (planets) to form spheres. Earth has a magnetic field that protects us from solar radiation.

3. Continued… Ironically, the magnetic poles are not at the North/South Poles!

4. Earth’s orbit has an elliptical shape… why is that important?

5. Time and Seasons The Earth is spherical… and can be divided into 360 0 It spins (rotates) in ~ 24 hours How many degrees does it turn in 1 hour? This is also the width of a time zone (15 o )! The International Date Line – the location where a day is added/subtracted Revolution – Earth’s motion around the Sun Remember…it’s elliptical!

6. Why do we have seasons? 1. Earth’s rotation 2. Earth’s revolution 3. Tilt of Earth’s axis

7. The Moon’s effect on Earth Tides

8. Tide demonstration http://oceanexplorer.noaa.gov/edu/learning/10_tides/acti vities/predicting_tides.html#activity http://oceanexplorer.noaa.gov/edu/learning/10_tides/acti vities/predicting_tides.html#activity

9. Moon phases Waxing phase – as the moon grows larger each night Waning phase – as the moon grows smaller Crescent…< 25% is showing Gibbous…> 25% is showing

11. Solar eclipse umbra Penumbra

12. Lunar eclipse