The document summarizes key concepts in earth science, including:
1) Constructive forces build up the earth's surface while destructive forces wear it away.
2) The lithosphere consists of tectonic plates that meet at boundaries and glide on the asthenosphere.
3) All continents were once joined in a supercontinent called Pangaea before separating due to sea floor spreading.
4) Sea floor spreading occurs at mid-ocean ridges as new crust is formed and plates move apart.
2. DIFFERENCE BETWEEN
CONSTRUCTIVE AND DESTRUCTIVE
FORCES
Constructive forces build up the earth’s surface
Destructive wear away earth’s surface
3. LAYERS OF EARTH
Lithosphere- consists of crust and top of mantle
Separates into plates
Meets at plate boundaries
Asthenosphere- located under lithosphere; what
the lithosphere glides on top of
4. PANGEA
All the continents were once joined together in a
super continent
Continents fit together like puzzle pieces
5. SEA FLOOR SPREADING
Two oceanic plates moving away from each other
(diverging)
The ocean floors move like conveyor belts,
moving the continents away from each other
New crust is formed where the plates are
spreading
6. SEA FLOOR SPREADING AND PLATE
TECTONICS
Convection currents is the engine that drives the
plates to move
9. WHAT HAPPENS WHEN PLATES
COLLIDE?
Oceanic/Oceanic- the older plate (more dense
plate) will subduct
Oceanic/Continental- oceanic plate subducts
because it is more dense
Continental/Continental- forms mountain ranges
12. FOCUS AND EPICENTER
Focus- point BENEATH Earth’s surface where
rock under stress breaks to cause an earthquake
Epicenter- point on the surface directly above the
focus
13. SEISMIC WAVES
P Waves- compress and expand the ground like
an accordion (happen first)
S Waves- vibrate from side to side and up and
down
Surface Waves- when waves reach the surface
(cause most damage)
21. MAGMA AND LAVA
Magma is molten rock under the ground
When magma reaches the Earth’s surface, it is
called lava
22. SILICA AND MAGMA’S VISCOSITY
Silica determines viscosity
The more silica, the more viscous a substance is
More silica magma is light colored and is too
sticky to flow far
Less silica magma flows readily and produces
dark colored lava
23. HOW DOES TRAPPED GAS EFFECT A
VOLCANO’S ERUPTION?
As magma rises toward the surface, the pressure
decreases and the dissolved gases begin to expand and
exert an enormous force