Download Notes 4.3

Notes Chapter 4
Earth’s Structure and Motions
Name
__ _____
4.3 Earth’s Revolution pgs. 80 – 83
1. Earth’s revolution
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_______________________ – one complete orbit around the sun = 1 year
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____________ days
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Leap year? _________________________________________________
___________________- tilt of axis is parallel throughout our orbit (N. Star)
2. Length of daylight
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Depends on two things:
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___________ ____ ____________
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_________________ in orbit – causes seasons
3. Proof of revolution
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__________________ – apparent shift in position of
nearby stars.
4. Path and rate of revolution
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Earth’s orbit is _________________
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Average distance _______________ miles (150
million km)
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_________________ – point in earth’s orbit
when farthest from the sun (______________ )
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___________________ – point in earth’s orbit
when nearest to sun (________________)
5. Effects of revolution and tilt
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_______________
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_______________ of daylight
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Indirect and direct rays
6. Seasons
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Solstices
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_______________ – June 21, direct
rays on T. of Cancer, _____________
day
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Winter – December 21, direct rays on
T. of ___________________, shortest day
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Equinox equal day and night sun rises due ______ and sets due ______
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____________________ – march 21 vertical rays at equator. 12 hrs.
Day and 12 hrs. night.
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____________________ – Sept 23 vertical rays at equator. 12 hrs.
Day and 12 hrs. night
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Label the diagram below with the seasons, date and vertical rays
Our axis has not always pointed to the same star and will change in the near
future.
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___________________–
earth not only rotates on its
axis … it also wobbles. This
wobble effect is a
phenomenon caused by
forces exerted by the sun on
the bulges of the earth at the
equator