Earth Science Ch 2 Review
What is the proportion of land area to sea area on the Earth? From studies of the hypsometric curve, approximately what proportion of the Earth's surface lies at elevations above 2 km?
-30% land and 70% sea. -Approximately 3% of earth surface lies above 2 km.
What are the principal layers of the Earth? What happens to earthquake waves when they reach the boundary between layers? How do the inner core and outer core differ from one another?
-Crust, Mantle, and Core -When earthquake waves reach the boundary between layers, seismic wavelength changes between layers. -The outer core is mostly liquidiron-nickel-sulfur and the inner core is mostly solidiron-nickel-alloy
What are the two most abundant chemical elements in the Earth? Describe the major categories of materials constituting the Earth. What are the two most abundant chemical elements in the Earth's crust?
-Iron 35% and Oxygen 30%. -The major categories of materials constituting Earth are organic compounds, metals, volatiles, glasses, rocks, minerals, and melts. -The two most abundant chemical elements in Earth's crust are Oxygen and Silicate.
What is the Earth's atmosphere composed of, and how does it differ from the atmospheres of Venus and Mars? Why would you die of suffocation if you were to eject from a fighter plane at an elevation of 12 km without taking an oxygen tank with you?
-The Earth's atmosphere is composed of mostly nitrogen 78.08% and oxygen 20.95%, whereas the atmosphere in Venus and Mars are composed mainly of CO2 gas -You would die because air pressure decreases as elevation rises so, the higher in the air you are the less oxygen you would have.
What is the difference between the lithosphere and the asthenosphere? Be sure to consider material differences and temperature differences. Which layer is softer and flows easier? At what depth does the lithosphere/asthenosphere boundary occur? Is this above or below the Moho?
-The Lithosphere is the outermost 100-150 km of Earth, behaves as a non-flowing rigid material, and is made of two components: the crust and upper mantle. -The Asthenosphere is in the upper mantle below the Lithosphere, is shallower under oceanic lithosphere, deeper under continental lithosphere, and flows as a soft solid. -The boundary occurs at around 150 km and this is below the Moho.
How do temperature and pressure change with increasing depth in the Earth? Be sure to explain the geothermal gradient.
As temperature and pressure change with increasing depth, the downward pressure of the earth crams matter together creating heat and as the pressure increases the matter also increases in temperature.
Why do astronomers consider the space between planets to be a vacuum, in comparison with the atmosphere near sea level?
Because there is an absence of matter and atoms between planets, but the Earth's atmosphere contains 2.7 x 1022 atoms per liter, meaning it has matter
What is the Moho? How was it first recognized? Describe the difference between continental crust and oceanic crust. Approximately what percentage of the Earth's diameter is within the crust?
The Moho discontinuity separates the crust from the upper mantle and is marked by a change in the velocity of seismic waves. -It was first recognized when Mohorovicic discovered that the velocity of seismic waves suddenly increased at a depth of a few tens of kilometers beneath the surface of continents, and suggested that this increase was caused by an abrupt change in the properties of rock -Continental crust underlies the continents and has a granitic composition. Oceanic crust underlies the ocean basins and is basaltic in composition. -.01% to 1% is the percentage of the Earth's diameter within the crust.
What observations led to the realization that the Earth is largely solid and that the Earth's mass is largely concentrated toward the center?
The observation that the average density was greater than surface density and density must increase with depth. Earthquakes gave clues because energy transmitted from an earthquake comes as a seismic wave which have been used to probe the interior of the earth and noticed changes with depth through pressure and temperature.
How does the Earth's magnetic field interact with solar wind? Be sure to consider the magnetosphere, the Van Allen radiation belts, and the aurora.
The solar wind interacts with Earth's magnetic field, distorting it and pointing it away from the sun. Fortunately, the magnetic field deflects most of these solar-wind particles, so they don't reach Earth's surface. The magnetic field serves as a shield against solar-wind particles. The region inside this shield is referred to as the magnetosphere. The Van Allen Belt is a region where the magnetic field strengthens, and traps both cosmic rays and solar-wind particles. It is like a second line of defense. But, some ions get through and follow the magnetic field lines to the polar regions of Earth creating auroraes.