Ch.4 Earth

1
Ch.4 Earths Structure and Motion

• Foucault pendulum
• Standard time zones
• Time meridian
• Prime meridian
• International date line
• Revolution
• Parallax
• Summer solstice
• Winter solstice
• Vernal equinox
• Autumnal equinox

• Vocabulary
• Geology
• Inner core
• Outer core
• Mantle
• Crust
• Lithosphere
• Asthenosphere
• Magnetic field
• Rotation
• Coriolis effect

2
4.1 Earths Formation

• Geology is the study of planet Earth, its
  structure and composition, and how it has changed
  over time.
• Origin
• Widely accepted at 4.6 billion years ago
• Big Bang theory
• Gravity pulled matter together into stars
• About 10 of the material surrounded the new Sun,
  formed planetesimals
• See diagram p. 70-71

3

• Earths Size and Shape
• Earth is 3rd closest planet to the Sun, after
  Mercury and Venus
• The Moon is approx. 1/6 the size (mass) of Earth.
• Earth is NOT a perfect sphere it is slightly
  flattened at the poles
• Total surface is about 510 km2
• About 149 km2 or 30 is land (continents, islands)

4

• Earths Interior
• Densest in the middle (mostly iron)
• Crust and upper-most mantle make up the
  lithosphere
• See diagram p. 72 chart p. 73

5
Earths Heat text. p.46-since Earths formation,
its slowly been losing heat-one heat source is
radioactive decay of Uranium -other heat sources
are the result of meteorite impacts, compression
due to gravity-Earths surface warms due to Sun
effectstemperature increases once gt70 m below
surface-rate is approx. 1C for every 40 m depth
6
4.2 Earths Rotation

• Evidence Foucaults pendulum in 1851 found
  evidence for Earths rotation
• Once per day approx. 24 hours (
• Earths rotation affects predominant wind
  patterns on Earth
• This is a result of the Coriolis Effect

7
Axis and Rate of Rotation

• Earth is tilted at 23to the plane of orbit
• Constancy of tilt is called parallelism
• Speed of rotation is 1690 km/hr at the equator,
  Squamish BC approx 1200 km/hr.
• 0 km/hr at North and South poles
• See p. 76 text

8
Effects of Rotation

• Time zones 24 in total
• Each approx. 15longitude (360/2415)
• International Date line is at 180E or W (middle
  of the Pacific)
• Coriolis effects on wind patterns also

9
4.3 Earths Revolution

• Revolves once/year 365.24 days around Sun
• Causes seasons
• Summer solstice when you get the most heat
• Winter solstice when you get the least
• Equinoxes when Northern and Southern hemispheres
  get the same amount of heat energy

10

• Do p. 86 1-10,15,16, 19-22
• BONUS 18