Transcript The Moon: Earth`s Fellow Traveler

The Moon:
Earth’s Fellow Traveler
Warm Up Questions
CPS Questions (1-2)
Chapter 2, Lesson 2
Lesson Overview
 The Moon’s size and distance from Earth
 The relationships between the Moon and
the Earth
 The Moon’s origins and surface
Chapter 2, Lesson 2
Quick Write
If you had been one of the Apollo 11
astronauts, what about the Moon
would you have been most curious to
see or experience for yourself?
(Note to teacher: Use “Pick a Student” button in CPS)
Chapter 2, Lesson 2
The Distance from the Earth
to the Moon
 Ptolemy calculated the
distance at 27.3 Earth
diameters
 Today we know Earth’s
diameter is 12,800
kilometers, or 8,000 miles
 The Moon is about 380,000
kilometers (240,000 miles)
from Earth
Chapter 2, Lesson 2
How the Moon’s Size is
Estimated
 An object’s angular size is
the angle between two
lines that start at the
observer and go to
opposite sides of the object
 Scientists can use the
Moon’s angular size plus
the distance from the Earth
to the Moon, to calculate
the diameter of the Moon
Chapter 2, Lesson 2
Why the Moon Appears to Be
Larger at Certain Times
Moon appears to be larger at some times
than others because its distance from
Earth varies
Chapter 2, Lesson 2
Reprinted by permission of Creators
Syndicate and John L. Hart FLP
Why the Moon Appears to Be
Larger at Certain Times, cont.
Its orbit is elliptical
The Moon appears to be larger when it is
at its perigee, or closest distance from the
Earth
It appears smaller when at its apogee, or
farthest distance from the Earth
Chapter 2, Lesson 2
Courtesy of Galileo Project , NASA
The Relationship Between
the Moon and the Earth
A tidal force is a gravitation force that
varies in strength and/or direction over an
object and causes it to deform
Moon’s gravity pulls harder on those parts
of Earth closer to it than on parts farther
away
Chapter 2, Lesson 2
The Relationship Between
the Moon and the Earth, cont.
Spring tides - exceptionally high and low
tides that occur at the time of the new
moon or the full moon, when the Sun,
Moon and Earth are approximately aligned
Neap tides are the tides that occur when
the difference between high and low tides
is least
Chapter 2, Lesson 2
The Relationship Between
the Moon and the Earth, cont.
Chapter 2, Lesson 2
Moon’s Rotation and
Revolution
In times past, the Moon must have gone
through a rotation period different from its
revolution
Tidal friction – the friction that results
from tides on a rotating object – has
slowed the Moon down
The Earth and the Sun cause tides on the
Moon
Tidal friction is at work on the Earth as well
Chapter 2, Lesson 2
How the Moon’s Location
Influences the Earth’s “Wobble”
Precession - the conical shifting of the
axis of a rotating object
The force acting on Earth to change its
spin is gravity
The precession of the Earth means that
eventually there will be a new “North Star”
Chapter 2, Lesson 2
The Moon’s Origin and
Surface
 The moonscape
has two principal
features:
1. The maria or “seas”
– lunar lowlands that
resemble seas when
viewed from Earth
2. The crated
mountainous
regions
Chapter 2, Lesson 2
Courtesy of NASA
The Moon’s Origin and
Surface, cont.
Craters are the result of the impact of
meteorites – interplanetary chunks of
stone or matter that have crashed into a
planet or moon from space
Volcanic eruptions did produce the maria
Impacts from large asteroids formed the
craters
Dark lava flooded the basins of the craters
to form the maria
Chapter 2, Lesson 2
Features of the Moon’s Crust
Moon’s crust ranges
from about 60
kilometers to 100
kilometers deep
Lunar mountains are
the result of millions of
ancient craters piled up
on top of one another
Chapter 2, Lesson 2
Four Theories of the
Moon’s Origins
1. Double Planet Theory - the Moon was
formed at the same time as the Earth
2. Fission Theory - the Moon formed from
material spun off from the Earth
3. Capture Theory - the Moon is made up
of Solar System debris captured by Earth
Chapter 2, Lesson 2
Four Theories of the
Moon’s Origins, cont.
4. Large Impact Theory
 Moon formed as the result of an impact between a
large (Mars-sized) object and the Earth
 The metal cores of the two bodies combined to
form the massive core of Earth
 The lighter material became the Moon
Chapter 2, Lesson 2
Learning Check
CPS Questions (3-4)
Chapter 2, Lesson 2
Activity 1: The Moon: Earth’s Fellow
Traveler Review Challenge
Use your textbook to identify the terms
and people to complete the worksheet
Chapter 2, Lesson 2
Activity 2: The Moon’s Origin
1. The text presents four different theories of
the Moon’s origin. As a group, review
pages 70-71 in the textbook and
complete the chart.
2. Then answer the reflection questions on
your own.
Chapter 2, Lesson 2
Activity 3: Just How Far?
1. Work together to solve the math
problems about distance
2. Be prepared to share your answers
Chapter 2, Lesson 2
Technology Enrichment:
Tides & the Moon
1. Visit the website link listed on your
worksheet and follow the step by step
directions.
2. Answer the questions and be prepared to
share your findings.
Chapter 2, Lesson 2
Review
Through time, we have become more
exact in our measurements of the Moon
and how far away it is
The Moon, the Earth and the Sun all have
gravitational influences on one another
The Moon’s mountains formed differently
from Earth’s
Chapter 2, Lesson 2
Review, cont.
The moonscape has two principal
features: the maria and the cratered
mountainous regions
There are four theories of the Moon’s
origins:
Double planet theory
Fission theory
Capture theory
Large impact theory
Chapter 2, Lesson 2
Review Questions
CPS Questions (5-6)
Chapter 2, Lesson 2
Summary
 The Moon’s size and distance from Earth
 The relationships between the Moon and
the Earth
 The Moon’s origin and surface
Chapter 2, Lesson 2
Next…
Done – The Moon:
Earth’s Fellow
Traveler
Next – The Sun and
Its Domain
Chapter 2, Lesson 2
Courtesy of SOHO-EIT
Consortium/ESA/NASA.