Earth Science Ch. 4 Study Guide
Quiz on Mon., October 1, 2007
General Things to Review:
-Definitions of vocab. words (within NOTES packet!) and word parts!
-Material covered in the ch. 4 worksheet packet
-Barron’s blue book Qs (p. 202 1, 3-5; p. 54-65 1-4, 8-10, 31-33)
-Magnetic Field Lab
-North Pole/Equator Rate of Rotation Activity
4.1
A. Earth’s Formation
-Know a general idea of what the nebular hypothesis is … especially that it
is the favored idea of how the solar system formed 4.6 billion yrs. ago from
a big cloud of gas, dust. Gravity caused cloud to shrink & speed of rotating
cloud increased.
***Spinning motion of Earth caused Earth to be sphere with bulges at
equator … = why Earth is NOT a perfect sphere (Know this!)***
B. Earth’s Size and Shape
-Know that E is NOT a perfect sphere (but we draw it as one due to size of
drawing … lose detail)
-Know … How do we know? B/c weight of an object is different, -depending on where it is on E (accounting for elevation) …
-What evidence supports E being almost a perfect sphere
-So an object weighs more near poles b/c it is closer to E’s center
-Weight vs. Mass
-Earth is smoother than billiard ball!
C. Earth’s Interior
-In its beginning, partially molten (liquid) Earth separated by density =
differentiation
-Know that this caused Earth to be separated into layers:
Densest material (iron, nickel) sunk to center to form inner & outer core.
-Be able to label crust, mantle, uppermost mantle, lithosphere,
asthenosphere, outer core and inner core
- layer of Earth that is LIQUID is OUTER CORE
-Movements in liquid outer core create Earth’s magnetic field
- Temp. & density increase w/ depth (into Earth, toward center)
-Mantle is SOLID, but the asthenosphere (a portion of the mantle) is a
ductile solid & therefore can flow over time
-Uppermost mantle & crust make up lithosphere (a brittle solid that breaks
= EQs)
D. Earth’s Heat
-Know Sources of Earth’s Heat:
1. Meteorite impacts & heat left over from E’s accretion (formation)
2. Compression in Earth’s interior
3. Decay of radioactive isotopes
-***Since Earth’s formation, Earth has slowly been losing heat***
E. Earth’s Magnetic Field
-Be able to use a topographic map to determine the # of degrees
separating geographic north & magnetic north – see bottom of map, left of
the map scale, to determine exact # degrees separating GN & MN for a
specific location
4.2 Earth’s Rotation
-Know what rotation and axis of rotation are
-Parallelism
-Precession- what is it? How much time does it take for 1 cycle?
-Axis of rotation is tilted 23.5 degrees from perpendicular
-Rate of rotation
***Speed of rotation is slower at poles, faster at equator
-Know effects of Earth’s rotation (see wkst on Sect. 4.2)
-Standard time zones are 15 degrees of longitude wide & that each time
zone is separated by a time meridian
-Know what the prime meridian & International Date Line are
4.3 Earth’s Revolution
-Difference between rotation & revolution
-Rate of revolution (1 full rev. in 1 yr.) & path slightly elliptical)
-Elliptical path causes distance between Earth & Sun to change throughout
year = changing speeds of E’s revolution and seasonal variations
-Hemisphere tilted toward sun gets more direct sunlight & has warmer
temp. & longer days
-Difference between summer solstice (longest day of yr) & winter solstice
(shortest day of yr)
-Which is more important for increased temps on E? angle of sun’s rays or
E’s distance from sun
-aphelion, perihelion