Exam review answers
Earth Science
2nd nine weeks
1. How do we get direct and indirect evidence about the Earth’s interior?
Direct – rock samples
Indirect – seismic waves
2. Draw and label the Earth’s layers. Which is the thickest? What is the inner core made of, what is
the outer core made of?
Crust
Mantel
Outer core
Inner core
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Thickest – mantle
Inner core – a dense ball of solid mental
Outer core – liquid iron and nickel
Where is there more pressure, on the Earth’s surface or in the center of the earth?
Center
What produces the earth’s magnetic field?
Outer core
Define constructive and destructive forces. Give an example of each.
Constructive – any natural process that builds up Earth’s surface
Ex: build up mountains and other landmasses
Destructive – any natural process that tears down or wears away Earth’s surface
Ex: erosion and weathering
Define convection, conduction and radiation. Be able to pick which one is being used in an
example (HINT!!! Study your heat transfer quiz!)
Convection- the transfer of thermal energy by the movement of a fluid
Conductions – the transfer of thermal energy form one particle of matter to another
Radiation – the transfer of energy by electromagnetic waves
What does the theory of continental drift state?
The continents were once joined together in a single landmass
Define Pangaea. How do we know it once existed?
The name of the supercontinent that existed millions of years ago. The occurrence of
Glossopteris on land masses that are now separated.
Why do Earth’s plates move? And what is the name of those plates located in the litoshpere?
How fast do they move?
Convection currents in earth’s mantle, Tectonic plates, very slow about 2 inches a year
Explain what happens as subduction occurs. The process by which oceanic crust sinks beneath a
deep-ocean trench and back into the mantel at a convergent plate boundary
Tell what happens at each of the following boundaries: Divergent, convergent, transform
Divergent – a plate boundary where two plates move away from each other
Convergent boundary – a plate boundary where two plates move toward each other
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Transform – boundary between two plates that are sliding past each other
Tell at which of the four boundary types the following happen:
Curst is not created or destroyed -transform
New crust is added- divergent
Earthquakes common -transform
Volcanic activity common - divergent
Mountain ranges form – convergent colliding and crumpling
Explain sea floor spreading and mid ocean ridge
Sea floor spreading – when two oceanic plates pull apart, magma rises and new crust is formed
Mid ocean ridge – a mountain range that runs along the middle of some oceans floors
Explain the difference between focus and epicenter.
Focus point in Earth’s interior where the energy release of an earthquake occurs
Epicenter – point on earth’s surface directly above where seismic energy is released
Define seismograph and seismic waves
Seismograph - instruments that red seismic activity
Seismic waves- waves generated by an earthquake
Explain primary waves and earthquakes.
Primary wave – seismic wave that moves rock particles back and forth in the same direction, the
first wave to reach Earth’s surface
Earthquakes – sudden shaking of the ground
At mid ocean ridges two places move _______________
Apart
Where do volcanoes form?
Plate boundaries, hot spots
What is lava?
When magma reaches the Earth’s surface
List the three classifications of volcanoes that describe their activity.
Extinct, dormant, or active
List the two types of volcanic eruptions.
Quiet and explosive
Define: pipe, vent, pyroclastic flow, litoshpere
Pipe – a long tube that extends form Earth’s crust up through the top of a volcano
Vent- opening where magma is forced up and glows out onto Earth surface as lava, forming a
volcano
Pyroclastic flow – is a mixture of hot gasses, ash, cinder, and bombs that flow down the sides of
a volcano when it erupts
Lithosphere – earth’s plates are puzzle pieces on the earth that make this up
What is Earth’s history divided into?
Smaller units called the geologic time scale (eon, era, period, epoch)
Define fossils and explain what scientists can learn from them.
Fossils – the preserved remains or traces of organisms that lived in the past
Scientists can describe past environments and the history of life
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Fossils allow them to tell how organisms have changed overtime.
Define half life, unconformity, trace fossils, law of superposition
Half life – the time it takes for half of the radioactive atoms in a sample of a radioactive element
to decay
Unconformity – gap in the geologic record where some rock layers have been lost because of
erosion
Trace fossils – footprints and trails
Law of superposition – helps geologists determine the relative age of rock layers
What gas, necessary for life, was lacking in Earth’s early atmosphere?
Oxygen
What caused the extinction of the dinosaurs and between what eras did it occur? Between the
Cenozoic and Mesozoic eras … asteroid from space
Define: Globe, index contour, topographic map, map key
Map key: aka legend, list of all the symbols used on a map
Topographic map is a map showing the surface features of an area
Index contour is every fifth contour line; they are darker and heavier than others
Globe sphere that represents the entire earth’s surface
29. What does the equator divide the Earth into?
the Northern Hemisphere and Southern Hemisphere.
30. What is the prime meridian the starting line for measuring?
longitude
31. What can a grid formed by lines of latitude and longitude be used for?
to find your location on Earth.
32. Define contour line and contour interval
Contour line connects points of equal elevation
Contour interval change in elevation from one contour line to the next
33. What do contour lines show?
Elevation, relief and slope
34. What do widely spaced contour lines mean?
Flat areas
35. What do v shaped contour lines pointing downhill show?
Ridge lines