Chapt 1 science continued

Who proposed the conecpt of continental drift?

Alfred Wegener

Which of Earth's layers is the thickest?

The mantle

List Earth's three main layers.

Crust, Mantle, Cores.

What causes convection currents in the mantle?

Heat from the core and mantle itself causes convection currents.

How is heat transferred?

Heat is transferred by conduction, convection or radiation.

in general, what happens to the density of a fluid as it becomes hotter?

Its density decreases.

Why does the rock on the ocean floor have a pattern of magnetic stripes?

The molten material cooled and hardened. the rock cooled, and the iron lined up in the direction of earths magnetic poles. It gave it a magnetic memory. (in stripes)

Why was Wegeners hypothesis rejected by most of the scientists of his day?

because he couldnt come up with a satisfactory explanation of the force that pushes or pulls the continents.

According to the hypothesis of continental drift, how would a map have changed over the last 250 million years?

A map wouldve changed because the continents split apart, and then the map wouldve been different.

What was alfred wegeners hyptothesis about the continents?

All the continents were once joined together in a single landmass and have since drifted apart.

How did fossils provide evidence for continental drift?

Because if he found a group of plant fossils one place, thne found another group of the same kind somewhere else, like across an ocean, it would have proved his hyptohesis of continental drift.

How would continental drift affect a continents climate?

Because if it was more north it was warm, but then when continental drift started happening, it mightve gotten pushed south farther.

Why is it difficult to determine Earth's inner structure?

Because you can't go inside earth because it is too hot. You have to use your evidence from rock samples and seismic waves.

What are the three types of heat transfer?

Conduction, convection and radiation.

Describe the type of movement that happens at each type of plate boundary.

Convergent - the crust move together Divergent - the crusts move away from each other Transform - The crusts slip past each other in opposite directions

What are the characteristics of the crust, mantle and core?

Crust - Hard rock, earth's outer layer Mantle - hot, solid, between the core and crust Core - Outer - Flowing iron and nickel; Inner - solid, dense ball of Nickel and Iron

What evidence supported his hypothesis?

Evidence from fossils, land features and climate change.

What is the evidence for Sea-Floor spreading?

Evidence from molten material, magnetic strips and drilling samples (rock ages)

What scientist helped to discover the process of sea floor spreading?

Harry Hess

How is heat transferred through space?

Heat is transferred through space by radiation.

What causes convection currents?

Heating and cooling of the fluid, changes in the fluids density, and the force of gravity combine to set convection currents in motion.

Classify each of the following layers as liquid, solid, or solid but able to flow slowly; lithosphere, asthenosphere, lower mantle, outer core, inner core

Lithosphere is solid. Asthenoshpere is solid, but able to flow slowly. Lower mantle is solid. Outer core is liquid. inner core is solid.

Along what feature of the ocean floor does sea floor spreading begin?

Mid-Ocean ridge / mantle

what features form where two continental plates form together?

Mountains

What do scientists think causes the movement of Earth's plates?

Movement of convection currents in the mantle is the major force that causes the movement of the plates.

Where would you except to find the oldest rock on the ocean floor?

Near the deep-ocean trench.

What is the main type of rock in oceanic and continental crust?

Oceanic - Basalt Continental - Granite

What is the main difference between the outer core and the inner core?

Outer core is flowing; inner core is solid

What causes seismic waves?

Seismic waves are caused when earthquakes occur.

Why is the pacific ocean shrinking?

Sometimes a deep-ocean trench swallows more oceanic crust then a mid-ocean ridge can produce. Then, if the ridge does not add new crust fast enough, the width of the ocean will shrink. In the pacific ocean, subduction through the many trenches that ring the ocean occur-ing faster then the new crust can be added.

What device is used to map the ocean floor?

Sonar

What happens at a deep ocean trench?

Subduction

What is likely to occur at a plate boundary where oceanic and continental crust collides?

Subduction occurs

How could coal be found so far near the south pole.

The coal couldve been in the north, but when the continent split because of alfreds hypothesis, it couldve gone south.

Name two layers of the Earth in which convection currents take place.

The mantle and the core.

What happens to oceanic crust at a deep ocean trench?

The material falls into the deep ocean trench and goes into the mantle to become newer material, starting the cycle over again.

How do rocks along the central valley of the mid-ocean ridge provide evidence for sea-floor spreading?

The rocks along the central valley are younger then the rocks near the trench, so if geologists took rock samples, they would see that the rock is newer and than that would prove the theory of sea-floor spreading.

What is the role of gravity in creating convection currents?

The role of gravity is the force pushing it.

What is the process of Sea-Floor spreading?

The sea floor spreads apart along both sides of a mid-ocean ridge, as new crust is added. As a result, the ocean floor move like conveyor belts, carrying the continents along with them.

What will happen to the convection currents in the mantle if Earth's interior eventually cools down?

They will stop because they are caused because of heat, but if there is no heat, the currents would stop.

How do geologists study Earth's interior?

Two types of main evidence - direct evidence from rock samples and indirect evidnce from seismic waves

According to wegener, how do mountains form?

When continents collide, their edges fold up and form mountains.

How are seismic waves used to provide evidence about Earth's interior?

When earthquakes occur, they produce seismic waves. Geologists and scientists use the speed of seismic waves and the paths they take reveal the structure of the planet.

How does new oceanic crust form?

When molten material erupts through the mid ocean ridge

What is the difference between the lithosphere and the asthenosphere? In which layer is each located?

the lihosphere is rigid and the asthenosphere is soft. They are both located in the Mantle.

What is the asthenosphere?

the soft layer of the mantle, under the lithosphere