Earth's Interior
How thick is the crust, usually?
5 -40 kilometers thick
What does asthenes mean in greek?
weak
The inner core
a dense ball of solid metal
What is the rock like just beneath Earth's surface?
its cool
Where is crust thickest?Thinnest?
under high mountains and thinnest beneath the ocean.
How thick can the crust be?
up to 70 kilometers thick beneath mountains
Where and how deep is the deepest mine in the world?
A gold mine in South Africa, reaches a depth of 3.8 kilometers (that only scratches the surface)
When does the rock get warmer?
about 20 meters down
Which crust consists mostly of granite?
continental crust
Continental Crust
crust that forms the continents
Why is the inner core solid?
extreme pressure squeezes the atoms of iron and nickel so much that they cannot spread out and become liquid
How do scientists divide the mantle?
into layers based on the physical characteristics of those layers
The outer core
is a layer of molten metal that surrounds the inner core
Granite
is a rock that usually is a light color and has a coarse texture
The Crust
is the layer of rock that forms Earth's outer skin
What happens after this rapid rise of temperature?
it increases more slowly but steadily
Asthenosphere?
it is soft and can bend like plastic
The Lower Mantle
its beneath the asthenosphere and its solid-extends all the way to Earth's core
Seismograph
measures seismic waves
What is the crust called beneath the ocean?
oceanic crust
What other substances do scientists think are in the core?
oxygen, sulfur, and silicon
On average how thick is the lithosphere?
100 kilometers thick
Overall how thick is the mantle
3,000 kilometers
What is pressure a result of?
A force pressing on an area
Why is the part of the mantle just beneath the lithosphere less rigid than the rock above?
Because it is hotter and under increasing pressure
Why is it surprising that the outer core is liquid?
Because of the enormous pressure
Why does pressure increase the deeper you travel inside Earth?
Because the weight of the rock above the pressure increases
What do scientists think liquid in the outer core creates?
Earth's magnetic field
What happens 20 meters below the surface?
For every 40 meters you descend from that point, the temperature rises 1 Celsius degree
What is another way geologists obtain rocks from Earths interior?
Forces inside Earth sometimes blast rock to the surface from depths of more than 100 kilometers
How have geologists learned about Earth's inner structure?
Geologists have used two main types of evidence to learn about Earth's interior: direct evidence from rock samples and indirect evidence from seismic waves
What is the core mostly made of?
Iron and nickel
What does drilling into Earth do for geologists?
It brings up samples of rocks
How is Earth's surface changing?
It's surface has been lifted up, pushed down, bent, and broken
What is the crust like compared to the layer beneath it?
Much thinner
Basalt?
Oceanic rock that is dark with a fine texture
What is Earth's mantle made up of?
Rock that is very hot, but solid
What do earthquakes produce?
Seismic Waves
What indirect method do geologists rely on to find information about Earth's interior?
Seismic Waves
What does most of the current evidence suggest about both parts of the core?
That both contain iron and nickel
What have scientists learned from seismic waves?
That earths interior is made up of several layers
What is about 40 kilometers beneath the surface?
The Mantle
Characteristics of Earth's Crust
The crust is a layer of solid rock that includes both dry land and the ocean floor
What are the three main layers of Earth?
The crust, the mantle, and the core
Why can't geologists dig a whole to the center of the earth?
The extreme conditions in earths interior prevent exploration far below the surface
What are the two parts of the core?
The liquid outer core and the solid inner core
What is beneath the crust?
The solid material of the mantle, a layer of hot rock
Lithosphere?
The uppermost part of the mantle and the crust together form a rigid layer called the lithosphere
What are the characteristics of the crust, mantle, and core?
These layers vary greatly in size, composition, temperature, and pressure
Why are there high temperatures inside Earth?
They are a result of heat left over from the formation of the planet and also radioactive substances inside Earth release energy
How is the uppermost part of the mantle similar to the crust?
They are both solid
What do geologists do with the samples of rocks?
They can make inferences about conditions deep inside Earth
How do geologists study seismic waves?
They record the seismic waves and study how they travel through Earth. The speed of the seismic waves and the path they take reveal the structure of the planet
What can you find on the crust?
rocks and mountains. it also includes the soil and water that cover large parts of Earth's crust
What kind of rock does the ocean floor mostly consist of?
rocks such as basalt
What does lithos mean in greek?
stone
What happens when you use a compass?
the compass needle aligns with the lines of force in Earth's magnetic field
