EAPS 100 EXAM 1 QUESTIONS
AND ANSWERS
What is a rock? - Answer- -Rocks are solids that are naturally occurring and made up of
tons of different minerals
What are the most common elements in the earth as a whole, in the earth's crust? -
Answer- -As a whole, Iron and oxygen are the most common, also silicon and
magnesium
-The core is primarily iron
-On the crust, oxygen is the most abundant and silicon is the second most abundant,
aluminum is the third
What is the most common class of minerals and why? - Answer- Silicates because
there are so many of them and they are responsible for most of the rocks in earths
crust.
What are the common rock forming minerals? How do they form (general processes)? -
Answer- The silicates like olivine, pyroxene, amphibole, they are formed by oxygen and
silicon combining
What is the most important structure in silicate minerals? - Answer- Tetrahedral. The
ration of oxygen to silicon determines how they will combine
Why do silicate materials become more complex as they crystalize from a melt? -
Answer- Because there is a decreased thermal vibration of molecules
Explain the expanding Universe Theory and its relationship to the Big Bang Theory.
According to the theory, when did the universe form? - Answer- -Edwin Hubble
discovered that galaxies were moving away from Earth
-Raisin-bread analogy: as the dough expands, each raisin moves farther away from the
others
-The Big Bang Theory: all matter and energy initially existed in an infinitesimally small
point, point exploded 13.8 Ga (billion years ago)... as the universe expands, the
distances between galaxies increase
How old is the Earth? - Answer- - ~About 9 billion years after The Big Bang
- ~4.6 billion years
, Describe how, according to the nebular theory, the Earth formed. - Answer- The
Nebular Theory:
-Large, slowly swirling nebulae (clouds) formed after 200 million years of the Big Bang
-Nebulae collapsed, leading to a formation of a protostar and then a star
-The transition from an undifferentiated cloud to a star system complete with planets
and moons takes about 100 million years
-Nebular Theory to formation of Earth:
Protoplanetary disk -> Plantesimals -> Protoplanets
-Analogy: Initial mixed dressing with oil and vinegar eventually differentiates due to
density differences
Distinguish between Big Bang nucleosynthesis and stellar nucleosynthesis. - Answer-
Formation of the Elements (H and He, and then everything else):
-Big Bang nucleosynthesis produced all the hydrogen and helium within the first 20
minutes of the explosion
-Later, nuclear fusion in stars (stellar nucleosynthesis) continues to form heavier
elements up to iron
-Elements heavier than iron form during supernova explosions (supernova
nucleosynthesis). First Generation Stars
Why isn't the Earth homogenous (it is layered), and why is it round? - Answer- Internal
Earth Differentiation:
-Internal temps of plantesimals increase with size.
-With melting, heavier objects move inward to form the core, and lighter material forms
the outer mantle.
Making the Earth round:
-Small planetesimals are cool and rigid and stay irregular in shape
-Large planetesimals become warm internally
-Gravity can make the warm rock flow and form a sphere
Why is the Earth's magnetic field important to life? - Answer- -Reflects solar wind with
high levels of radiation coming from the sun which would destroy our ozone layer and
harm Earth
-Van Allen radiation belts trap energetic solar wind and cosmic rays
How do temperature and pressure change with increasing depth in the Earth? - Answer-
-Molecules pack together more tightly at the base of the atmosphere, so pressure
changes with elevation. As elevation increases, temperature and pressure decrease
-As depth in the Earth increases, pressure decreases and temperature increases to a
certain point where it eventually stays the same, resulting in melting rock
What information is used to understand the character of the Earth's interior? - Answer- -
Lithosphere: rigid crust and upper mantle
-Asthenosphere: flowing mantle just below lithosphere
-Both are mechanical boundaries
-Crust, mantle, and core are compositional boundaries
AND ANSWERS
What is a rock? - Answer- -Rocks are solids that are naturally occurring and made up of
tons of different minerals
What are the most common elements in the earth as a whole, in the earth's crust? -
Answer- -As a whole, Iron and oxygen are the most common, also silicon and
magnesium
-The core is primarily iron
-On the crust, oxygen is the most abundant and silicon is the second most abundant,
aluminum is the third
What is the most common class of minerals and why? - Answer- Silicates because
there are so many of them and they are responsible for most of the rocks in earths
crust.
What are the common rock forming minerals? How do they form (general processes)? -
Answer- The silicates like olivine, pyroxene, amphibole, they are formed by oxygen and
silicon combining
What is the most important structure in silicate minerals? - Answer- Tetrahedral. The
ration of oxygen to silicon determines how they will combine
Why do silicate materials become more complex as they crystalize from a melt? -
Answer- Because there is a decreased thermal vibration of molecules
Explain the expanding Universe Theory and its relationship to the Big Bang Theory.
According to the theory, when did the universe form? - Answer- -Edwin Hubble
discovered that galaxies were moving away from Earth
-Raisin-bread analogy: as the dough expands, each raisin moves farther away from the
others
-The Big Bang Theory: all matter and energy initially existed in an infinitesimally small
point, point exploded 13.8 Ga (billion years ago)... as the universe expands, the
distances between galaxies increase
How old is the Earth? - Answer- - ~About 9 billion years after The Big Bang
- ~4.6 billion years
, Describe how, according to the nebular theory, the Earth formed. - Answer- The
Nebular Theory:
-Large, slowly swirling nebulae (clouds) formed after 200 million years of the Big Bang
-Nebulae collapsed, leading to a formation of a protostar and then a star
-The transition from an undifferentiated cloud to a star system complete with planets
and moons takes about 100 million years
-Nebular Theory to formation of Earth:
Protoplanetary disk -> Plantesimals -> Protoplanets
-Analogy: Initial mixed dressing with oil and vinegar eventually differentiates due to
density differences
Distinguish between Big Bang nucleosynthesis and stellar nucleosynthesis. - Answer-
Formation of the Elements (H and He, and then everything else):
-Big Bang nucleosynthesis produced all the hydrogen and helium within the first 20
minutes of the explosion
-Later, nuclear fusion in stars (stellar nucleosynthesis) continues to form heavier
elements up to iron
-Elements heavier than iron form during supernova explosions (supernova
nucleosynthesis). First Generation Stars
Why isn't the Earth homogenous (it is layered), and why is it round? - Answer- Internal
Earth Differentiation:
-Internal temps of plantesimals increase with size.
-With melting, heavier objects move inward to form the core, and lighter material forms
the outer mantle.
Making the Earth round:
-Small planetesimals are cool and rigid and stay irregular in shape
-Large planetesimals become warm internally
-Gravity can make the warm rock flow and form a sphere
Why is the Earth's magnetic field important to life? - Answer- -Reflects solar wind with
high levels of radiation coming from the sun which would destroy our ozone layer and
harm Earth
-Van Allen radiation belts trap energetic solar wind and cosmic rays
How do temperature and pressure change with increasing depth in the Earth? - Answer-
-Molecules pack together more tightly at the base of the atmosphere, so pressure
changes with elevation. As elevation increases, temperature and pressure decrease
-As depth in the Earth increases, pressure decreases and temperature increases to a
certain point where it eventually stays the same, resulting in melting rock
What information is used to understand the character of the Earth's interior? - Answer- -
Lithosphere: rigid crust and upper mantle
-Asthenosphere: flowing mantle just below lithosphere
-Both are mechanical boundaries
-Crust, mantle, and core are compositional boundaries
