Unit 1: Earths Dimensions

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Unit 1 Earths Dimensions

• Topic Change and Earths Shape
• Objectives
• 1. Differences between cyclic and non-cyclic
  changes
• 2. Introduce evidence for Earths Shape

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Objective 1

• Graphs that show patterns illustrate a cyclic
  change

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Cyclic changes

• Day and night?
• Yes
• Seasons
• Yes
• Earthquakes
• No

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Objective 1

• A BOUNDARY between the affected parts of the
  environment that causes an exchange of energy is
  called an
• INTERFACE
• Examples
• layers of the atmosphere
• weather fronts

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Cyclic and the environment

• If the change is cyclic, then it is said to be
  predictable!!!
• Examples
• The end of school?
• Yes
• Tornadoes
• No

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How did they prove the Earth to be round?

• Ships appearing to sink as it travels over the
  horizon
• Polaris (North Star) changes altitude directly
  with you latitude
• Eclipses of the Earths shadow on the moon
• Satellite Imagery

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Ships appear to sink
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Polaris Changes in Altitude
90º
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Locating Polaris
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Is the Earth Perfectly round?

• The Earth is called an oblate spheriod
• It is flattened at the poles and bulged at the
  equator
• How does weight determine that the Earth is not
  perfectly round?

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Weight!!!

• We are further from the center of the Earth at
  the equator
• This means we weigh LESS!!!
• We are closer at the poles
• We weigh MORE!!!!

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• At the Poles we are closer to the center
  stronger gravity more weight

Center of Earth center of gravity
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The Oblate Spheroid

• The difference is small
• We can not see it with the naked eye
• It still appears like a sphere
• Be careful on multiple choice