Download File - Earth and Environmental Science and Biology

Catalyst
1.What are the main results of
Earth’s rotation?
2.Why does the Earth’s distance
from the sun vary?
3.Explain what causes the
seasons.
Explain precession and its effect on the seasons
Agenda
Explain nutation and its effect on the seasons.
IN: Drawing Earth’s Motion
THROUGH: Precession/Nutation Notes
OUT: Lesson Reflection
PRACTICE: Making Models
Notebook
Objectives
How does the Earth move?
P.
P.
Title: How does the Earth move?
Title: Precession and Nutation
Why are places near the equator hotter?
On earth, the equator receives more sunshine than do the poles. This is due to
simple geometry of the earth's curvature, a given amount of sunshine in a beam
falling on the equator, which points directly at the sun, has a much more intense
effect than the glancing rays spread over a much larger area of the curving surface
near the poles. In addition, extensive ice and snow at the poles reflects back to space
some of the sun's energy that reaches the earth.
Much more sunshine is absorbed to heat the earth at the equator. This means the
land at the equator becomes hotter than the poles. If we had no atmosphere or
oceans, the equator would become too hot for life as we know it, and the poles too
cold. However, the atmosphere and oceans take some of the excess heat from the
equator to the poles, making both habitable to humans. An interesting connection to
make is that if the earth were heated evenly at all latitudes there would be no winds
or ocean currents.
Positivity

Input: Left Top: Create the following chart on
the top of your page. Sketch a picture to show
rotation and revolution.
Rotation
Revolution
Precession
Nutation
What’s your sign?
Astronomy vs. Astrology
• Astronomy is the study of the universe.
• Astrology is a system of horoscopes that claim
to explain aspects of a person's personality
and predict future events in their life based on
the positions of the sun, moon, and other
planetary objects at the time of their birth.
Why Astrology is not Science
• Your zodiac sign corresponds to the position of
the sun relative to constellations as they
appeared more 2,200 years ago!
• Zodiac signs were originally determined by
which constellation the Sun was "in" on the
day you were born.
Astronomy
• Early astronomers observed the Sun traveling
through the signs of the Zodiac in the course
of one year, spending about a month in each.
• However, a phenomenon called precession
has altered the position of the constellations
we see today.
Astronomy
• Ancient astrologers, the Earth continually
wobbles around its axis in a 26,000-year cycle.
• Over the last 2,500 years, this wobble means
the signs have slipped one-tenth—or almost
one whole month—of the way around the sky
• Most horoscope signs are different after
considering the changes caused by precession
So what does precession look like?
• http://www.youtube.com/watch?v=0qHjtp4cd
CA
Precession
• 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
http://vimeo.com/3110658
• 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
MSL Prep
In 13,000 years, precession will cause
A. no change to the Earth’s seasons
B. the seasons on Earth to be reversed
C. the Earth’s axis to be pointing toward a “new”
North Star
D. the Earth’s axis to be pointing toward the same
North Star
MSL Prep
In 13,000 years, precession will cause
A. no change to the Earth’s seasons
B. the seasons on Earth to be reversed
D. the Earth’s axis to be pointing toward the same
North Star
So the earth moves in 3 ways:
1. Rotation (spinning)
2. Revolution (taking a lap around the sun)
3.Precession (changing direction of the axis)
And let’s add one more…
The Earth is CRAZY!
•
•
•
•
1. Rotation
2. Revolution
3. Precession
4. Nutation
Nutation
: 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
MSL Prep
Nutation causes
A.
B.
C.
D.
no change to the Earth’s seasons
significant changes to the Earth’s seasons
no change in the Earth’s tilt
significant changes to the Earth’s tilt
MSL Prep
Nutation causes
B. significant changes to the Earth’s seasons
C. no change in the Earth’s tilt
D. significant changes to the Earth’s tilt
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 …
Make your own model!
Your job is to create and explain a scientific model
that describes:
• the daily changes on Earth due to its rotation
• the seasonal changes due its the tilt
• revolution of the Earth around the sun.
• Precession and nutation of Earth’s axis
You can use any of the supplies that I have supplied
to create your model.
Working Norms
• Volume: 6 inch voice
• All group members must contribute to making
the model.
• Use supplies SUSTAINABLY – take only what
you need, and leave some for other groups!
• Return all supplies when the timer runs up.