104 terms

Science Chapter 1 - Plate Tectonics

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Iceland's volcano added _____ sq. km of land to Earth's surface.
2.5
Rocks have both chemical and _____ features.
Physical
_____ are the features formed in rock and soil by water, wind, and waves.
Landforms
Geologists divide the forces that change the surface into two groups: _____ and _____ forces.
Constructive, destructive
The formation of the island of Surtsey is an example of _____ forces at work.
Constructive
The ocean waves that wear away Surtsey's shoreline are an example of _____ forces.
Destructive
When earthquakes occur, they produce _____ waves.
Seismic
The pressure is the force _____ on a surface area.
Pushing
The pressure inside Earth _____ as you go deeper.
Increases
The crust is thinnest beneath the _____ and thickest under high mountains.
ocean
The crust ranges from 5-40 _____ thick.
kilometers
The crust beneath the ocean is called oceanic crust and it consists mostly of dense rocks such as _____.
Basalt
Continental crust consists mainly of less dense rock such as _____.
Granite
The mantle is a layer of _____ rock.
Hot
The uppermost part of the mantle _____ with depth.
Increases
The material that forms this part of the mantle is somewhat soft and can bend like _____.
Plastic
The metals iron and _____ make up both parts of the core.
Nickel
The outer core is a layer of molten _____.
Metal
The inner core is a dense ball of _____ metal.
Solid
The extreme pressure _____ the atoms of iron and nickel so much that they cannot spread out and become liquid.
Squeezes
Currents in the outer core create Earth's _____ field.
Magnetic
The north-seeking end of the _____ needle points to Earth's magnetic north pole.
Compass
The movement of energy from a warmer object to a _____ object is called heat transfer.
Cooler
There are three types of _____: radiation, conduction, and convection.
Heat Transfer
The transfer of energy through _____ space is called radiation.
Empty
Radiation allows _____ to warm Earth's surface.
Sunlight
Heat transferred by _____ of particles of matter is called conduction.
Direct contact
Convection is heat transfer by the movement of a heated _____.
Fluid
During convection, heated particles of fluid begin to _____, transferring heat energy from one part of the fluid to another.
Flow
As the particles move faster, they spread _____.
Apart
As the fluid becomes cooler, its _____ increases.
Density
A convection current is the flow that transfers heat within a _____.
Fluid
Convection currents will eventually _____ when all of the material has reached the same temperature.
Stop
Convection currents flow in the _____.
Asthenosphere
The convection currents in the asthenosphere have been flowing in the Earth for more than 4 _____ years.
Billion
Wegener's hypothesis was that all the continents had once been joined together in a single _____ and have since drifted apart.
Landmass
Pangea means "_____"
All lands
Wegener's idea that the continents slowly moved over Earth's surface became known as continental _____.
Drift
Wegener gathered _____ from different scientific fields to support his ideas.
Evidence
A mountain range in South Africa lines up with one in _____.
Argentina
European coal fields match up with similar coal fields in _____.
North America
Mesosaurus and Lystrosaurus have been found in places now separated by _____.
Oceans
Glossopteris fossils have been found in _____ in Africa, South America, Australia, india, and Antarctica
Rocks
The "seeds" of the plant fossils were too _____ to have been carried by the wind and too _____ to have survived a trip by ocean waves.
Large, fragile
Fossils of tropical _____ are found Spitsbergen.
Plants
Deep scratches in rocks showed that continental _____ once covered South Africa.
Glaciers
Because Wegener couldn't identify the _____ of continental drift, most geologists rejected his idea. (Some even resorted to toilet papering his house)
Cause
Some areas of the deep-ocean floor are teeming with _____.
Life
In the mid-1900s, scientists mapped the mid-ocean ridge using _____.
Sonar
Using sonar, the time it takes for the _____ to arrive indicates the distance to the object.
Echo
There are places where the ridge pokes above the surface of the _____.
Ocean
A steep-sided _____ splits the top of the mid-ocean ridge for most of the length.
Valley
Hess proposed that the ocean floors move like _____ belts, carrying the continents along with them.
Conveyor
As molten material _____, it forms a strip of solid rock in the center of the ridge.
Cools
Hess realized that the sea floor spreads apart along both sides of the mid-ocean ridge as new _____ is added.
Crust
The S.S. Alvin's crew found strange rocks shaped like _____.
Pillows
The presence of the "pillow rocks" showed that molten material has erupted again and again from _____ along central valley of the mid-ocean ridge.
Cracks
Evidence shows that Earth's magnetic poles have _____ themselves.
Reversed
Earth's magnetic poles reversed last _____ years ago.
780,000
Scientists discovered that the _____ hold a record of reversals in Earth's magnetic field.
Strips
The magnetic stripes can be thought of as setting thousands of tiny _____ needles in cement.
Compass
The magnetic stripes pattern is the _____ on both sides of the ridge.
Same
The farther away from the ridge the samples were taken, the _____ the rocks were.
Older
Ocean floor plunges into deep underwater _____.
Canyons
A deep ocean trench forms where the oceanic crust _____ downward.
Bends
Subduction is the process by which the ocean floor sinks beneath a deep ocean trench and back into the _____.
Mantle
Subduction and sea floor spreading can change the _____ and shape of oceans.
Size
If the ridge does not add new crust fast enough, the _____ of the ocean will shrink.
Width
The Pacific Ocean is _____ because it is ringed with many trenches.
Shrinking
As the Atlantic's floor spreads, the continents along its edges also _____.
Move
The lithosphere is broken into separate sections called _____.
Plates
A scientific theory is a well tested concept that _____ a wide range of observations.
Explains
Plate Tectonics is the geological theory that states that pieces of Earth's lithosphere are in constant, slow _____, driven by convection currents in the mantle.
Motion
No plate can _____ without affecting the other plates surrounding it.
Move
Plate movement can cause earthquakes, _____, mountain ranges, and deep sea trenches.
Volcanoes
A transform boundary is a place where two plates slip past each other, moving in _____ directions.
Opposite
Earthquakes occur frequently at _____ boundaries.
Transform
Most divergent boundaries occur at the _____ ridge.
Mid ocean
The Great Rift Valley in east Africa marks a deep _____ in the African continent.
Crack
Eventually, the floor in the Great Rift Valley may drop enough for the _____ to fill the gap.
Sea
When two plates converge, the result is called a _____.
Collision
When two plates collide, the _____ of the plates determines which one comes on top.
Density
Continental plates are mostly low _____ granite.
Density
The collision of convergent boundaries _____ the crust into mountain ranges.
Squeezes
The North American and Eurasian plates are floating apart at a rate of 2.5 cm per year, about as fast as your _____ grow.
Fingernails
A break in the Earth's crust where rocks have slipped past each other is called a _____.
Fault
Continental crust consists mainly of _____.
Granite
_____ is the process by which oceanic crust sinks beneath trenches.
Subduction
Earth's lithosphere is broken into separate sections called _____.
Plates
Scientists who study the forces that make and shape the planet Earth are called _____.
Geologists
In the convection current of a pan of soup, the cooler, denser fluid _____.
Sinks
The transfer of energy through empty space is called _____.
Radiation
_____ is who first proposed the theory of continental drift.
Alfred Wegener
_____ is what erupts through the valley of the mid ocean ridge.
Molten material
Heat transfer by the movement of the heated fluid is called _____.
Convection
A _____ is a place where two plates slip past each other.
Transform boundary
The _____ is the part of the mantle that can bend like plastic.
Asthenosphere
The process that continually adds new material to the ocean floor is _____.
Sea floor spreading
Fossils of tropical plants found on an island in the Arctic Ocean are evidence for the theory of _____.
Continental drift
A rift valley forms along a _____ boundary on land.
Divergent
The supercontinent that began to break apart about 225 million years ago is called _____.
Pangea
As oceanic crust moves away from the _____, it cools and becomes more dense.
Mid ocean ridge
_____ is a measure of how much mass there is in a volume of a substance.
Density
The lithosphere includes all of the _____ and part of the mantle.
Crust