Transcript Earth`s Structure and Motion

Chapter 4:
Earth’s Structure and Motion
4.1: Earth’s Formation
 4.2: Earth’s Rotation
 4.3: Earth’s Revolution

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4.1: Earth’s Formation
A.
Origin of the Solar
System
1. Nebular Hypothesis
a.
b.
c.
Cloud of gas and dust
rotating slowly
Rotation speed increased
Material gathered to its
center
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4.1: Earth’s Formation
d. Interior (core) became
very hot = hydrogen
fusion = Sun born
e. Excess material went into
space = planetesimals =
beginning of Solar
System
Draw figure on pp 70-71
•
Origin of the solar system.
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4.1: Earth’s Formation
B.
Earth's Size and Shape
1.
2.
Planetesimals collected more objects developing into
planets/moons
What is a sphere called that bulges at the center?
Oblate Spheroid
3.
How do we know that Earth is spherical shaped bulging
at the center?
By measuring the weight of an
object at several locations on earth
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4.1: Earth’s Formation
4. 149 million sq. km.
(29%) is dry land
5. 361 million sq. km.
(71%) is covered by
water
6. The total surface of
Earth is ...
510 million KM=55 united states
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4.1: Earth’s Formation
C.
Earth's Interior
1.
Space collisions have
changed Earth to
look the way it does
presently
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4.1: Earth’s Formation
2. Layers of the Earth
Inner Core - Solid Iron
and Nickel
b. Outer Core - Liquid Iron
and Nickel
c. Mantle (thickest layer)
Iron, Silicon, Magnesium
a.
i.
ii.
Asthenosphere - Slush
like layer
Lithosphere - More rigid
than the asthenosphere
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4.1: Earth’s Formation
3. Crust (earth's surface,
thinnest layer) Rock
D.
Earth's Heat
1.
How did originally
generate heat?
Meteorite impact, compression
and Radioactive decay
2.
Why is earth loosing heat
presently? Rocks lose heat to the atmosphere,
crustal thickness varies, and radioactivity
decreases with time.
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4.1: Earth’s Formation
3. Why does the
temperature in caves
remain constant?
Because the sun’s warmth and
winter’s cold cannot penetrate there.
4. After about 70 meters
temperatures will begin
to increase about 1o C
every 40 m of depth
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4.1: Earth’s Formation
E.
Earth's Magnetic Field
A.
The North Pole attracts a
compass needle - the
positive end of a bar
magnet
B.
The South Pole repels a
compass needle - the
negative end of a bar
magnet
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4.1: Earth’s Formation
C. The hypothesis
explaining Earth's
magnetic north/south is
the liquid iron moving
across Earth's weak
magnetic field = a
stronger magnetic field
is produced
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4.2: Earth’s Rotation
A.
Evidence for Rotation
1.
What is significant about Foucault's pendulum and it 11o
shifts each hour? It proves that the earth is rotating
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4.2: Earth’s Rotation
2.
Evidence of Earth's rotation is
seen in the Coriolis Effect Northern Hemisphere winds
are deflected to the right
relative to Earth's surface;
which way are winds
deflected in the Southern
Hemisphere?
To the Left
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4.2: Earth’s Rotation
B.
Axis and Rate of
Rotation
Orbital Plane - an
imaginary flat surface
that Earth orbits the
sun in.
2. Earth's axis lies at a
23.5o tilt to its orbital
plane
1.
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4.2: Earth’s Rotation
3. Why does the Earth rotate
at different speeds at
Because points at the equator have
farther to travel than points at the
different latitudes?
poles in the same amount of time.
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4.2: Earth’s Rotation
C.
Effects of Rotation
1.
Earth rotates
counterclockwise =
Sun appears to rise
in east
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4.2: Earth’s Rotation
2. Measuring time
Sidereal Day = 23 hours 56 minutes; Earth rotates 360o
b. Solar Day = 24 hours (sunrise to sunrise = 'true day'); Earth
rotates ~ 361o
c. Solar Noon - the sun is at its highest point
a.
A.
Moves westward 1o every 4 minutes or 15o every hour = Time Zones
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4.2: Earth’s Rotation
C.
Effects of Rotation Standard Time Zones
Divisible by 15o or one hour = time meridian
b. Prime Meridian is in Greenwich
a.
i.
ii.
West of Greenwich time moves back (earlier)
East of Greenwich time moves forward (later)
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4.2: Earth’s Rotation
4. International Date Line
Change the date (not the time)
b. In the Pacific Ocean
c. Moving west = one day later
d. Moving East = one day earlier
a.
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4.3: Earth’s Revolution
A.
Evidence for Revolution
1.
2.
3.
Revolution = Orbit
Different constellations
are visible at different
seasons (pp 714-717)
What is parallax and how
can you demonstrate it
with a pencil?
Apparent shift in position of
distant objects. Hold a pencil up
and look at it with one eye open.
Then close that eye and look at
it with your other eye open.
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4.3: Earth’s Revolution
B.
Path and Rate of
Revolution
1.
Earth's revolution is the
same as it rotation, what
direction is this?
Counterclockwise
2.
The average distance the
Earth is from the sun is
150,000,000 km (1 au)
a.
b.
Perihelion - when Earth is
nearest the sun = 147.6
million km; ~ January 2
Aphelion - when Earth is
farthest away from the sun =
152.4 million km; ~ July 4
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4.3: Earth’s Revolution
3. Zenith - the point directly
above the observer
4. Altitude - Angular distance
between the horizon and
sun's position.
i.
ii.
Sun is at its zenith = an
altitude of ...
Sun at its horizon = an
altitude of ...
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4.3: Earth’s Revolution
C. Effects of Revolution &
Tilt
1.
In addition to Earth's
revolution it’s tilt plays a
large role in temperature,
seasons, and days
a. Hemisphere tilted
towards the sun = direct
sunlight = warmer
temperatures and longer
days.
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4.3: Earth’s Revolution
B. Hemisphere tilted away from the sun = indirect
sunlight = cooler temperatures and shorter days.
C. Summer Solstice - first day of summer, ~ June 21,
longest day, Northern hemisphere @ max tilt towards
sun. North Pole = 24 hrs. of ... South Pole = 24 hrs. of ...
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4.3: Earth’s Revolution
C.
Effects of Revolution and Tilt
e.
Winter Solstice - first day of winter, ~ December 21, shortest
day, Northern Hemisphere @ max tilt away from sun.
North Pole = 24 hrs. of darkness
b. South Pole = 24 hrs. of daylight
a.
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4.3: Earth’s Revolution
F. Vernal Equinox ~ March 21 / Autmnal Equinox ~
September 22
a.
b.
c.
Both day and night are equal length
Neither hemisphere tilts towards the sun
Sun overhead the equator at noon
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