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Chapter 4: Chapter 4: Earth’s Structure and MotionEarth’s Structure and Motion

4.1: Earth’s Formation4.1: Earth’s Formation 4.2: Earth’s Rotation4.2: Earth’s Rotation 4.3: Earth’s Revolution4.3: Earth’s Revolution

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4.1: Earth’s Formation4.1: Earth’s Formation

A.A. Origin of the Solar Origin of the Solar SystemSystem

1. Nebular Hypothesis1. Nebular Hypothesisa.a. Cloud of gas and dust Cloud of gas and dust

rotating slowlyrotating slowly

b.b. Rotation speed Rotation speed increasedincreased

c.c. Material gathered to its Material gathered to its centercenter

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4.1: Earth’s Formation4.1: Earth’s Formation

d. Interior (core) became d. Interior (core) became very hot = hydrogen very hot = hydrogen fusion = Sun bornfusion = Sun born

e. Excess material went e. Excess material went into space = into space = planetesimals = planetesimals = beginning of Solar beginning of Solar SystemSystem

Draw figure on pp 70-71Draw figure on pp 70-71• Origin of the solar syste

m.

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4.1: Earth’s Formation4.1: Earth’s FormationB.B. Earth's Size and ShapeEarth's Size and Shape

1.1. Planetesimals collected more objects developing Planetesimals collected more objects developing into planets/moonsinto planets/moons

2.2. What is a sphere called that bulges at the center?What is a sphere called that bulges at the center?

3.3. How do we know that Earth is spherical shaped How do we know that Earth is spherical shaped bulging at the center?bulging at the center?

Oblate Spheroid

By measuring the weight of an object at several locations on earth

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4.1: Earth’s Formation4.1: Earth’s Formation

4. 149 million sq. km. 4. 149 million sq. km. (29%) is dry land(29%) is dry land

5. 361 million sq. km. 5. 361 million sq. km. (71%) is covered (71%) is covered by waterby water

6. The total surface of 6. The total surface of Earth is ...Earth is ...

510 million KM=55 united states

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4.1: Earth’s Formation4.1: Earth’s Formation

C.C. Earth's InteriorEarth's Interior1.1. Space collisions Space collisions

have changed have changed Earth to look the Earth to look the way it does way it does presentlypresently

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4.1: Earth’s Formation4.1: Earth’s Formation

2. Layers of the Earth2. Layers of the Eartha.a. Inner Core - Solid Iron Inner Core - Solid Iron

and Nickeland Nickelb.b. Outer Core - Liquid Outer Core - Liquid

Iron and NickelIron and Nickelc.c. Mantle (thickest layer) Mantle (thickest layer)

Iron, Silicon, Iron, Silicon, MagnesiumMagnesiumi.i. Asthenosphere - Asthenosphere -

Slush like layerSlush like layerii.ii. Lithosphere - More Lithosphere - More

rigid than the rigid than the asthenosphereasthenosphere

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4.1: Earth’s Formation4.1: Earth’s Formation

3. Crust (earth's 3. Crust (earth's surface, thinnest surface, thinnest layer) Rocklayer) Rock

D.D. Earth's HeatEarth's Heat1.1. How did originally How did originally

generate heat?generate heat?

2.2. Why is earth loosing Why is earth loosing heat presently?heat presently?

Meteorite impact, compression and Radioactive decay

Rocks lose heat to the atmosphere, crustal thickness varies, and radioactivity decreases with time.

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4.1: Earth’s Formation4.1: Earth’s Formation

3. Why does the 3. Why does the temperature in caves temperature in caves remain constant?remain constant?

4. After about 70 meters 4. After about 70 meters temperatures will temperatures will begin to increase begin to increase about 1about 1oo C every 40 m C every 40 m of depthof depth

Because the sun’s warmth and winter’s cold cannot penetrate there.

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4.1: Earth’s Formation4.1: Earth’s Formation

E.E. Earth's Magnetic Earth's Magnetic FieldField

A.A. The North Pole The North Pole attracts a compass attracts a compass needle - the positive needle - the positive end of a bar magnetend of a bar magnet

B.B. The South Pole repels The South Pole repels a compass needle - a compass needle - the negative end of a the negative end of a bar magnetbar magnet

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4.1: Earth’s Formation4.1: Earth’s Formation

C. The hypothesis C. The hypothesis explaining Earth's explaining Earth's magnetic magnetic north/south is the north/south is the liquid iron moving liquid iron moving across Earth's weak across Earth's weak magnetic field = a magnetic field = a stronger magnetic stronger magnetic field is producedfield is produced

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4.2: Earth’s Rotation4.2: Earth’s Rotation

A.A. Evidence for RotationEvidence for Rotation1.1. What is significant about Foucault's pendulum and it 11What is significant about Foucault's pendulum and it 11oo

shifts each hour?shifts each hour? It proves that the earth is rotating

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4.2: Earth’s Rotation4.2: Earth’s Rotation2. Evidence of Earth's rotation is 2. Evidence of Earth's rotation is

seen in the seen in the Coriolis EffectCoriolis Effect - - Northern Hemisphere winds Northern Hemisphere winds are deflected to the right are deflected to the right relative to Earth's surface; relative to Earth's surface; which way are winds which way are winds deflected in the Southern deflected in the Southern Hemisphere?Hemisphere?

To the Left

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4.2: Earth’s Rotation4.2: Earth’s RotationB.B. Axis and Rate of Axis and Rate of

RotationRotation1.1. Orbital PlaneOrbital Plane - an - an

imaginary flat surface imaginary flat surface that Earth orbits the that Earth orbits the sun in.sun in.

2.2. Earth's axis lies at a Earth's axis lies at a 23.523.5oo tilt to its orbital tilt to its orbital planeplane

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4.2: Earth’s Rotation4.2: Earth’s Rotation3. Why does the Earth rotate 3. Why does the Earth rotate

at different speeds at at different speeds at different latitudes?different latitudes?

Because points at the equator have farther to travel than points at the poles in the same amount of time.

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4.2: Earth’s Rotation4.2: Earth’s Rotation

C.C. Effects of RotationEffects of Rotation1.1. Earth rotates Earth rotates

counterclockwise = counterclockwise = Sun appears to rise Sun appears to rise in eastin east

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4.2: Earth’s Rotation4.2: Earth’s Rotation2. Measuring time2. Measuring time

a.a. Sidereal DaySidereal Day = 23 hours 56 minutes; Earth rotates 360o = 23 hours 56 minutes; Earth rotates 360ob.b. Solar DaySolar Day = 24 hours (sunrise to sunrise = 'true day'); Earth = 24 hours (sunrise to sunrise = 'true day'); Earth

rotates ~ 361rotates ~ 361oo

c.c. Solar NoonSolar Noon - the sun is at its highest point - the sun is at its highest pointA.A. Moves westward 1Moves westward 1oo every 4 minutes or 15 every 4 minutes or 15oo every hour = Time Zones every hour = Time Zones

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4.2: Earth’s Rotation4.2: Earth’s RotationC.C. Effects of Rotation Standard Time ZonesEffects of Rotation Standard Time Zones

a.a. Divisible by 15Divisible by 15oo or one hour = or one hour = time meridiantime meridianb.b. Prime Meridian is in Greenwich Prime Meridian is in Greenwich

i.i. West of Greenwich time moves back (earlier)West of Greenwich time moves back (earlier)ii.ii. East of Greenwich time moves forward (later)East of Greenwich time moves forward (later)

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4.2: Earth’s Rotation4.2: Earth’s Rotation4. International Date Line4. International Date Line

a.a. Change the date (not the time)Change the date (not the time)b.b. In the Pacific OceanIn the Pacific Oceanc.c. Moving west = one day laterMoving west = one day laterd.d. Moving East = one day earlierMoving East = one day earlier

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4.3: Earth’s Revolution4.3: Earth’s Revolution

A.A. Evidence for RevolutionEvidence for Revolution1.1. Revolution = OrbitRevolution = Orbit

2.2. Different constellations Different constellations are visible at different are visible at different seasons (pp 714-717)seasons (pp 714-717)

3.3. What is parallax and how What is parallax and how can you demonstrate it can you demonstrate it with a pencil?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 Revolution4.3: Earth’s RevolutionB.B. Path and Rate of Path and Rate of

RevolutionRevolution1.1. Earth's revolution is the Earth's revolution is the

same as it rotation, what same as it rotation, what direction is this?direction is this?

2.2. The average distance the The average distance the Earth is from the sun is Earth is from the sun is 150,000,000 km (1 au)150,000,000 km (1 au)a.a. PerihelionPerihelion - when Earth is - when Earth is

nearest the sun = 147.6 million nearest the sun = 147.6 million km; ~ January 2km; ~ January 2

b.b. AphelionAphelion - when Earth is - when Earth is farthest away from the sun = farthest away from the sun = 152.4 million km; ~ July 4152.4 million km; ~ July 4

Counterclockwise

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4.3: Earth’s Revolution4.3: Earth’s Revolution

3. 3. ZenithZenith - the point directly - the point directly above the observerabove the observer

4. 4. AltitudeAltitude - Angular distance - Angular distance between the horizon and between the horizon and sun's position.sun's position.i.i. Sun is at its zenith = an Sun is at its zenith = an

altitude of ...altitude of ...ii.ii. Sun at its horizon = an Sun at its horizon = an

altitude of ...altitude of ...

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4.3: Earth’s Revolution4.3: Earth’s RevolutionC. Effects of Revolution & C. Effects of Revolution &

TiltTilt1.1. In addition to Earth's In addition to Earth's

revolution it’s tilt plays a revolution it’s tilt plays a large role in temperature, large role in temperature, seasons, and daysseasons, and days

a.a. Hemisphere tilted Hemisphere tilted towards the sun = direct towards the sun = direct sunlight = warmer sunlight = warmer temperatures and longer temperatures and longer days.days.

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4.3: Earth’s Revolution4.3: Earth’s RevolutionB. Hemisphere tilted away from the sun = indirect B. Hemisphere tilted away from the sun = indirect

sunlight = cooler temperatures and shorter days.sunlight = cooler temperatures and shorter days.

C. C. Summer SolsticeSummer Solstice - first day of summer, ~ June 21, - first day of summer, ~ June 21, longest day, Northern hemisphere @ max tilt towards longest day, Northern hemisphere @ max tilt towards sun. sun. North Pole = 24 hrs. of ... South Pole = 24 hrs. of ...North Pole = 24 hrs. of ... South Pole = 24 hrs. of ...

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4.3: Earth’s Revolution4.3: Earth’s RevolutionC.C. Effects of Revolution and TiltEffects of Revolution and Tilt

e.e. Winter SolsticeWinter Solstice - first day of winter, ~ December 21, - first day of winter, ~ December 21, shortest day, Northern Hemisphere @ max tilt away shortest day, Northern Hemisphere @ max tilt away from sun.from sun.a.a. North Pole = 24 hrs. of darkness North Pole = 24 hrs. of darkness b.b. South Pole = 24 hrs. of daylightSouth Pole = 24 hrs. of daylight

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4.3: Earth’s Revolution4.3: Earth’s RevolutionF. Vernal Equinox ~ March 21 / Autmnal F. Vernal Equinox ~ March 21 / Autmnal

Equinox ~ September 22Equinox ~ September 22a.a. Both day and night are equal lengthBoth day and night are equal lengthb.b. Neither hemisphere tilts towards the sunNeither hemisphere tilts towards the sunc.c. Sun overhead the equator at noonSun overhead the equator at noon