Transcript lava

Everybody Read to Find Out:
• How the layers of the earth
are ordered and what the
names of the layers are
1. The center of the earth consists of
hot rock and is called the inner core
(solid iron and nickel).
2. There is also an outer core (liquid
iron and nickel).
3. The next level is hot, molten rock
called mantle.
4. The layer that we walk on is the
crust.
1. The Crust
1. The earth’s outermost layer of
rock.
2. 5-20 MILES THICK!!
3. Made up of loose materials, like
rocks, seabed.
4. Has mountains, ocean floor,
volcanoes, and continents.
2.
The Mantle
1. The second layer between
the crust and outer core
2. Is solid rock except for the
part next to the crust,
where there is thick liquid
3. 1,800 MILES THICK!!
3.
The Outer Core (creates the magnetic field).
1. The outer part of the core is liquid and
HOT!
2. It gets hotter the deeper you go (around
9,000 degrees F in the center—your oven
only goes to about 600 degrees F).
3. It’s so hot that rock melts. Melted rock is
called MAGMA. When it erupts through a
volcano, its called lava.
4. When the lava cools, that lava will harden
and form new soil and rock, which will
become part of the Earth’s crust.
5. 1,400 MILES THICK!
• Earth’s outer core is melted. The
mass metal moves. As it moves, it
causes the solids inner core to spin.
Scientist believe this motion, along
with heat, creates a magnetic field.
• Like a bar magnet, Earth has south
and north magnetic poles. Earth’s
magnetic field makes compass needle
point north.
4. The Inner Core
1. 800 MILES TO CENTER!
2.Shaped like a ball, or
sphere.
3.Solid with iron and other
minerals.
Everybody read to find out:
1. What makes the earth’s crust
move
2. The definition of plate tectonics
3. What forces act on Earth’s
crust
(P. C-18-C-21)
Effects
Cause
The inside of the
earth is very hot,
and it always
releases a lot of
energy.
This energy causes
things to move in the
earth (rocks, plates,
etc.)
The earth has many
different landforms.
They include
mountains, hills, rivers,
canyons, plateaus, and
many other things.
Plate Tectonics
1. Plate Tectonics
a. Explains how plates (large
bodies of rock) move slowly around
the earth on partly melted rock
2. Plates
a. A large section of the earth’s
crust that moves as one unit
b. There are 8 large plates and
several smaller plates.
Plate Tectonics
As these plates float, they move in three
different ways. Each way that they move has
a special name associated with the boundary
where two plates meet.
Fault -- the place where two plates meet.
Types of plate movement:
1. Convergent -- where two plates move
together
2. Divergent – where two plates are
drifting apart.
3. Sliding – where the plates slide past one
another.
Already
knew
New Info
Wow
!
Wonder
?
•Layers of
Earth
•There are 7
continents.
•Earth’s plates
move in 3 ways
(convergent,
divergent, &
sliding).
•Plate
Tectonics
Theory says
that Earth is
made up of
plates.
•Alfred
Wegener
thought up the
Continental
Drift Theory.
•The CD
Theory is that
the continents
move together
and then away
from each
other.
•Also, he
thought the
continents
were all joined
once.
•Wegener
named the
huge continent
Pangaea.
•The MidAtlantic Ridge
is a HUGE
mountain
range on the
ocean floor
(10,000 feet).
•It is crazy to
think that
plants moved
with the land
mass.
•Will we ever
see big
changes in
Earth?
Volcanoes
1. What are they?
a. An opening in the earth’s surface.
2. How do they form?
a. Magma (melted rock) from
the mantle sometimes pushes
upward.
b. The crust usually blocks it, but
sometimes it seeps through cracks in
the crust. When it builds up inside a
“magma chamber”, the pressure
starts to increase and then---BAM!!!
What happens after they erupt?
a. The magma explodes through a main
vent in the volcano.
b. A deep hole called a crater is often
left on top of the volcano.
c. The erupting magma is called lava.
d. Gases, volcanic bombs, ash, and melted
rock also burst from inside the volcano.
e. The lava layers and ash layers build up
around the outside of the volcano.
4. Interesting Facts:
a. Hawaii was formed by volcanoes
erupting in the Pacific Ocean.
b. The two types of volcanoes are
erupting and oozing.
c. Lava can flow up to 50 mph but usually
just flows 10 mph.
3.
Connecting Learning
1. Do you think Pangaea once existed?
Why or why not?
2. Use the diagram on p. 21. In which
direction does each of the continents
seem to be moving? How might Earth
look several million years from now?
3. Look at the map of the earthquakes
and volcanoes and Earth’s plates (p.
22). What do you notice?
4. What are you wondering now?
Earthquakes
1. What causes earthquakes?
a. Sudden shifts in the earth’s rock
layers cause earthquakes
2. The focus, or epicenter, is where the
earthquake begins.
3. During an earthquake, the plates might:
a. Meet in a rubbing way (shoulder to
shoulder)--sliding
b. Spread away from each other
(divergent)
c. Meet in a pushing way (subduction)-convergent
New plates can be created during an
earthquake (especially at mid-ocean
ridges).
5. A seismograph is used to measure
earthquakes.
a. The Richter scale is used
to give them a number.
b. People cannot feel earthquakes
between a 1-2 on the scale.
c. An earthquake that receives a
7-8 destroys buildings.
6. Earthquakes
a. Shake and destroy land, homes,
and buildings
b. Create land by creating
mountains and valleys
4.
3 Different Types of Rocks
Scientists classify rocks in 3 main groups
based on how they were formed.
1. Igneous Rocks (Fact: Igneous means “fiery”)
a. How they form: When magma
reaches the surface, it becomes
lava.
b. This hot, molten rock cools and
hardens to form igneous rock.
c. Characteristics: Igneous rocks
vary in size, shape, color, and
texture.
Examples: basalt, pumice, obsidian
2. Sedimentary Rocks
a. Form in water from “sediment”,
which is grains and bits of rock that
were created by erosion or
weathering.
b. Fact: The sediment builds up over
many years and becomes cemented
together to form sedimentary rock.
c. Characteristics: These rocks are
layered. The layers tell the story
about how the rock was formed.
They can also have fossils, which tell
a story, too!
d. Examples: sandstone, limestone,
shale, and conglomerate
3. Metamorphic Rocks (means “change”)
a. Formed from another rock by heat and
pressure.
b. Usually form beneath the
earth’s crust (which means they
often heat up and become magma
again—it’s a cycle—the Rock Cycle!)
c. Fact: Both igneous and
sedimentary rocks can change into
metamorphic rocks.
d. Characteristics: These rocks are
usually harder than the rocks that
they were at first.
e. They may have “bands” which look
like stripes or layers from different
minerals pressed together by the
heat and pressure.
Rocks and Minerals
1. Minerals are made up of elements
and compounds.
2. Rocks are made up of minerals.
3. As minerals form, their atoms and
molecules form patterns that are
crystal shapes.
4. Scientists identify minerals by:
1. luster (how light bounces off of
it)
2. streak (color of powder left
when a mineral is rubbed against
a surface)
3. hardness (Moh’s Hardness
Scale)
4. cleavage (how a mineral breaks
apart)
5. density
6. color
1.
Weathering and Erosion
Physical (mechanical) weathering happens when
the earth’s crust is exposed to water, air, and
changes in temperature.
a. Rocks can wear away, making
smaller rock pieces, or sediments.
b. Freezing water expands, or takes up
more space and can cause rocks to
crack.
2. Chemical weathering happens when gases in
the air chemically react with other elements
and minerals.
a. Acid rain can dissolve limestone
rocks.
3. Erosion
a. Is the carrying away of
weathered rock by gravity,
water, wind, and ice
b. Erosion can wash away
boulders and mountains!
Examples: soil washed onto the
sidewalk, crumbling rocks on
buildings, holes in the road, cracked
sidewalks, plants/roots growing by
sidewalks, muddy streams
Examples of Erosion and
Weathering
• Sea cliffs form when a rocky shore erodes at
approximately the same rate throughout an area.
This results in a steep walled structure. The cliff
moves landward as the waves attack its base.
Examples of Erosion and
Weathering
• A gully caused by severe rainstorms.