Astronomy

1
Astronomy

• Starlog 1 What is astronomy?
• Objective Students will describe the difference
  between rotation and revolution in written notes.

2
Astronomy is

• the study of the moon, stars, and other objects
  in space

3
Difference between rotation and revolution.

• Rotation
• When an object in space spins on its axis
• Earths rotation on its axis causes day and night

• Revolution
• The movement of one object around another
• Earths revolution around the sun is called a
  year.

4
Rotation and Revolution
5
Why is there an extra day in February every
fourth year?

• Earths orbit takes 365 ¼ days. To account for
  the ¼ day we add an extra day every fourth year.
  We call that year leap year.

6
Why do we have seasons?

• Earth has seasons because its axis it tilted as
  it moves around the sun.

7
Seasons Video Clip
8
Seasons in the Hemispheres
9
Solstice and Equinox

• Solstice
• Two days of the year where the noon sun is
  overhead at either 23.5 degrees south or 23.5
  degrees north.

• Equinox
• Two days of the year where neither hemisphere is
  tilted toward or away from the sun
• Equinox means equal night

10
Chapter 1 Section 1 Review

• Why does Earth have day and night?
• Why does Earth have seasons?
• What is the difference between rotation and
  revolution?
• What is leap year?

11
Homework for Tonight

• Read Chapter 1 Section 1
• Define key terms for Section 1 on page 45
• Complete the Sharpen your Skills activity on
  page 15