Chapter 8- Plate Tectonics Flashcards
What is a long row of towering mountains?
Ridge
What is a long narrow canyon in the ocean floor?
Trench
Which layer of earth is solid and made mostly of iron?
Inner core
Which layer is made mostly of iron mixed with smaller amounts of other materials?
Outer core
Which layer is made of oxygen, combined with silicon, magnesium, and iron ore?
Mantle
Which layer is made of oxygen, silicon, aluminum, iron, and calcium? Also the thinnest layer
Crust
Which plate is most of the United States on?
North American Plate
Which plate is Hawaii on?
Pacific Plate
Why didn’t scientists accept the idea of continental drift?
Wegner couldn’t answer the question “What force could be strong enough to move whole continents?”
Do hot liquids float or sink? Do they weigh more or less?
Float. They weigh less.
Which boundary is sea floor spreading found at?
Spreading boundary
How many plates is the lithosphere broken into?
20
How is an earth quakes epicenter related to its focus?
The epicenter is directly over the focus
True or false?
The inner part of earth’s crust is hot, melted rock.
False.
True or false?
The temperature at Earth’s core is as hot as the sun
True
True or false?
Earth’s crust and the outer mantle make up the lithosphere
True
True or false?
The lithosphere is broken into plates that float on melted rock
True
True or false?
Tectonic plates are found on continents
False
The outermost layer of earth?
Crust
Earths crust and the solid part of the mantle
Lithosphere
What is the inner most layer of earth?
The core
The layer of earth just below the crust is called?
The mantle
True or false?
Earth’s crust contains most of Earth’s mass
False
True or false?
The outer core is liquid and the inner core is solid
True
True or false?
The ocean floor contains deep trenches and mountains
True
True or false?
Convection currents in the ocean cause tectonic plates to move
False
True or false?
Reversing magnetic fields in rock proved new crust is forming on the ocean floor
True
What is the theory that continents drifted apart in the past and continue to do so today called?
Continental drift
New crust is formed by _____ that cools on the ocean floor
Magma
The force that moves Earth’s played is called _________.
Convection
True or false?
When one plate slides under another, volcanoes and ocean trenches can occur
True
What is the area where 2 plates meet?
Plate boundaries
What is a break in the Earth’s crust
Fault
Theory stating that pieces of the lithosphere constantly move on top of a layer of partly melted rock is called
Plate tectonics
Deep ocean trenches can form at ______ boundary
Colliding
Huge valleys can form at a _____ boundary
Fracture
Earth quakes can form at a _____ boundary
Fracture
Mountains can form at a ____ boundary
Colliding
True or false?
Most volcanoes can’t be seen because they lie on the ocean bottom
True
True or false?
Most earth quakes and volcanoes occur at plate boundaries
False
The under ground point where the earth quake occurs is the_____
Epicenter
An instrument called a ______ detects tremors
Seismometer
__________ from satellites measure the movements of earths plates
Laser beams
