Upcoming SlideShare
×

# Sect 9.1

575 views

Published on

Published in: Education
0 Likes
Statistics
Notes
• Full Name
Comment goes here.

Are you sure you want to Yes No
• Be the first to comment

• Be the first to like this

Views
Total views
575
On SlideShare
0
From Embeds
0
Number of Embeds
5
Actions
Shares
0
11
0
Likes
0
Embeds 0
No embeds

No notes for slide

### Sect 9.1

1. 1. 6 th Grade Science Chapter 9 Sun-Earth-Moon System Notes Section 9.1
2. 2. <ul><li>How did people long ago know the Earth was spherical? </li></ul><ul><li>Aristotle in 350 B.C. observed that the Earth cast a curved shadow on the moon. Early sailors saw North Star move when they sailed north or south. </li></ul><ul><li>What is Earth’s axis of rotation? </li></ul><ul><li>Earth’s axis is the imaginary vertical line around which the earth spins. </li></ul>Key Questions 1 The Tadpole Galaxy
3. 3. Aristotle 350 B.C.
4. 5. Sailors see the mast of an approaching ship first, and the rest of the ship appearing gradually, as if the ship were coming over the crest of a hill.
5. 7. <ul><li>What is the Earth’s magnetic field? </li></ul><ul><li>The Earth’s magnetic field is generated by interaction of its iron core and rotation. This field protects Earth from harmful solar radiation. </li></ul><ul><li>What is the distance from the earth to the sun? </li></ul><ul><li>On January 3 the Earth is 147 million km from the sun. On July 4 it is 152 million km from the sun. </li></ul>Key Questions 2 The Sombrero Galaxy
6. 10. <ul><li>How far is the Earth tilted on its axis? </li></ul><ul><li>Earth’s axis is tilted 23.5 0 from a line drawn perpendicular to the plane of its orbit. </li></ul><ul><li>Why does Earth have seasons? </li></ul><ul><li>Summer occurs in the hemisphere tilted toward the sun. Winter occurs in the hemisphere tilted away from the sun. </li></ul>Key Questions 3
7. 13. http://www.learner.org/jnorth/tm/ReasonsBack.html
8. 14. Spring
9. 15. Summer
10. 16. Fall
11. 17. Winter
12. 18. <ul><li>What is a solstice? </li></ul><ul><li>The solstice is the day when the sun reaches its greatest distance north or south of the equator- summer solstice June 21, winter solstice Dec 21. </li></ul><ul><li>What is an equinox? </li></ul><ul><li>An equinox occurs when the Sun is directly above the Earth’s equator- spring equinox March 21, fall equinox is September 21. </li></ul>Key Questions 4