Notebook
Agenda
Objectives
How does the Earth move?
EEn.1.1.2.C. Explain precession and its effect on the seasons
EEn.1.1.2.D. Explain nutation and its effect on the seasons.
IN: Drawing Earth’s Motion
THROUGH: Precession/Nutation Notes
OUT: Lesson Reflection
PRACTICE: Making Models
Title: Precession and Nutation
Date: 2/28/13
Pages:
Input: Left Top
• Draw a picture of the 2 main motions of the
Earth (rotation and revolution).
So what does precession look like?
• http://www.youtube.com/watch?v=0qHjtp4cd
CA
• The Earth’s axis is tilted at a 23.5º angle
: the change in direction of the Earth’s
axis, but without any change in tilt
-Like the wobbling motion of a spinning top
• 1 precessional cycle: approximately 26,000 years
• Minor effect on the seasons
The North Star
• Our North Star is currently Polaris
• Because of precession, in 13,000 years our
North Star will be Vega
: The wobbling/swaying motion during
the precession of our axis.
• This causes a 1 degree change in the tilt of the
Earth’s axis.
• No effect on the seasons
Output (Left Bottom)
• Reflect on what we’ve learned today by
finishing the following sentences.
– Today, I learned …
– I was surprised to find …
– I wonder what would happen if…
– The important thing about …