MOTIONS OF EARTH, MOON,

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MOTIONS OF EARTH, MOON, SUN.REVIEW BOOK
TOPIC 42005-2006
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I) Apparent Motions of Celestial Objects.
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apparent motion

• is a motion that an object appears to make.
• it can be real or an illusion.
• example
• sun and stars
• moving from
• east to west
• across the sky.

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Daily Motion of Stars.

• move in an arc (or complete circle) around
  Polaris (the North Star).
• move from east to west.
• travel at a rate of 15o/hr. (360 o /24 hrs)

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Apparent Motions of the Planets.

• has motion that is similar to that of the stars.
• a second motion occurs over a period of weeks to
  months.
• retrograde motion - occurs when the planet
  appears to make a backward loop.
• Retrograde Motion

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Apparent Motions of Earth's Moon.

• moon moves from east to west.
• the moon rises 50 minutes later each day.

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Apparent Motions of the Sun.

• arc path, from east to west.
• changes its position, length, and altitude with
  the seasons.
• draw picture

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Summer Solstice June 21
zenith
Equinox March 21 Sept 23
Winter Solstice Dec 21
W
N
S
E
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Suns Position

• Spring and Fall Sun rises due East and sets due
  West.
• Summer Sun rises in the NE and sets in the NW.
• Winter Sun rises in the SE and sets in the SW.

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Duration of Daylight

• Spring and Fall 12 hr daylight 12 hr darkness.
• Summer period of daylight is longest.
• Winter period of daylight is shortest.

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Altitude of the Sun

• Only between latitudes 23.5oN 23.5oS can the
  noon sun be directly overhead.
• The noon sun is never directly overhead anywhere
  in the continental United States.

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REVIEW QUESTIONS p. 53 1-14
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4.2) Models that help explain Apparent Celestial
Motions.
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Geocentric Model

• earth-centered model.
• earth is stationary and most objects revolve
  around it.
• could not easily explain the apparent motions of
  the planets.
• could not explain behavior of a Foucault Pendulum.

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Geocentric Model
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Heliocentric Model

• sun-centered model.
• earth rotates on its axis and revolves around the
  sun, and the moon revolves around the earth.
• explains all apparent motions
• explains Foucault Pendulum,
• can be used to predict the motions of the planets.

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REVIEW QUESTIONS p. 55 15-19
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4.3) Actual Earth Motions.

• Earth moves with the Milky Way Galaxy as the
  Universe expands.
• Earth moves around the center of the Milky Way
  Galaxy with our solar system.
• Earth revolves around the sun.
• Earth rotates on its axis.

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Rotation of Earth

• spins on its axis.
• axis imaginary line
• through the planet from
• the North Pole to the
• South Pole.
• axis is tilted 23 1/2o
• north end of axis is pointed towards Polaris
  (North Star).
• rotates from West to East.
• 360o in 24 hours rate of 15o/hr.
• Counterclockwise from above North Pole.

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Evidence of Earth's Rotation.
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1)Observations from Space.
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2)Foucault Pendulum

• when the pendulum is allowed to swing freely, its
  path will appear to change.
• while the
• pendulum swings,
• the earth rotates
• under the
• pendulum.

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3)Coriolis Effect (link)
EVIL SANTA
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3)Coriolis Effect (link)

• objects moving at Earth's surface appear to be
  deflected from a straight line path.
• deflection is to the
• right in the Northern
• Hemisphere.
• deflection is to the
• left in the Southern
• Hemisphere.
• occurs with rockets,
• ocean currents, and winds.

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Evidence of the Earth's Revolution around the Sun.

• change of seasons
• (If the Earth did not revolve around the sun,
  the same part of the Earth would tilt towards the
  sun all the time)

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• different constellations are seen during each
  season.
• apparent diameter of the sun changes during the
  year.

spring
winter
summer
fall
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REVIEW QUESTIONS p. 58 20-27
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4.4) Earth and Moon Motions and time.
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Local Time

• is time based on the rotation of Earth as
  reflected in motions of the sun.
• all places on the same north-south line (meridian
  of longitude) have the same local time.

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Local Solar Time

• the sun reaches its highest point in the sky at
  solar noon.

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Time Zone or Standard Time

• 24 separate time zones in 15-degree-wide bands
  have been established.
• Each band has a difference of one hour.
• time gets earlier as you move to the west.

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REVIEW QUESTIONS p. 60 28-40
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4.5) Actual Motions of Earth's Moon
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The revolution of the moon around Earth as Earth
revolves around the sun results in

• Phases of the moon.
• Tides.
• Eclipses.

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The moons revolution

• the moon revolves around Earth in an elliptical
  orbit.
• The moons orbit is tilted about 5o from Earth's
  orbit.
• Period of revolution is 27 1/3 days.

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Moon Phases

• half of the moon is always receiving light from
  the sun at any given time.
• an observer on Earth sees varying amount of this
  lighted half moon phases.
• phases change from right to left.
• DRAW PHASES !!!!

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• REVIEW QUESTIONS p. 55 15-19
• REVIEW QUESTIONS p. 58 20-27
• REVIEW QUESTIONS p. 60 28-40

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Tides

• tides
• the cyclic rise and fall of ocean water on Earth
  caused by the gravitational attraction of the
  moon and to a lesser degree the sun.

Bay of Fundy 18m tidal range
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high tide - (a bulge of water)

• occurs directly under the moons position.
• there is also a high tide on the opposite side of
  the earth.

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Low tide

• Levels of water are low.
• Occur at right angles to the position of high
  tides.
• The gravitational pull of the moon is the least.
• diagram

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Low
NP
High
High
moon
Earth
Low
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SPRING TIDES

• high tides are higher and low tides are lower.
• (large tidal range)
• Occurs when the Earth, the moon and the sun are
  in a straight line.
• the sun enhances the tidal effect.
• occurs during new and full moon phases.
• diagram

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new
full
NP
SUN
moon
Earth
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NEAP TIDES

• the high tides are lower and low tides are
  higher.
• (smaller tidal range).
• occurs when the sun is pulling at a right angle
  to the moon.
• occurs during the quarter phases.
• diagram

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quarter
NP
SUN
Earth
quarter
moon
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Eclipses

• lunar eclipse
• occurs when the moon revolves into the shadow of
  the Earth.
• occurs during the full moon phase.
• diagram

link
pics
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full
NP
SUN
moon
Earth
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• solar eclipse
• occurs when the shadow of the moon falls on the
  Earth.
• occurs during the new moon phase.
• diagram

link
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new
NP
SUN
Earth
moon
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REVIEW QUESTIONS p. 64 41-57