Transcript Earth*s Structure: How the Earth Formed

10/7
Earth’s Structure: How the Earth Formed
Bellwork 10/7
Copy the questions and answer them on
your green bellwork log.
1. What did our Sun and planets form
from?
2. What event started the solar system’s
formation?
3. What force caused tiny particles of dust
to stick together?
How did Earth form?
The solar system formed when a cloud of
gas, ice, and dust, called a nebula, was
pulled together by gravity.
• The nebula shrank, flattened into a disk, and began to
rotate.
• The materials in the center of the disk formed the Sun.
• Planets began to take shape from the remaining bits of
material.
• Earth formed as gravity pulled small particles together, that
would collide, build mass, and collect more particles.
• Early Earth generated thermal energy in its interior, making
the rocks of the planet soft enough to flow.
• Gravity pulled in the irregular bumps, the rock flowed, and
Earth developed a relatively even spherical surface.
How did Earth develop its spherical
shape?
• Gravity is the force that every
object exerts on every other
object because of their masses.
• All objects on or near Earth are
pulled toward Earth’s center by
gravity.
• The early Earth’s gravity pulled
all material down, forcing it to
have a smooth surface
The Formation of Earth’s Layers
• Earth developed distinct layers of different material after
thermal energy melted some of the material and it began to
flow.
• Different materials formed layers according to their densities.
• Density is the amount of mass in a material per unit volume
and can be described as D = m/V (density is mass divided by
volume).
• If two materials have the same volume, the denser material
will have more mass.
• When ancient Earth started melting, the densest materials
sank and formed the innermost layer.
• The least dense
materials stayed at the
surface and formed a
separate layer, and
materials with
intermediate densities
formed layers in
between.
Bellwork 10/11
Copy the questions and answer them on your green
bellwork log.
1. The layers of the Earth are arranged according to
_________________________.
2. Where is the densest material located?
3. Where is the least dense material located?
Clues to Earth’s Interior
• Deep mines and wells give scientists
hints about Earth’s interior.
• Scientists also use earthquake waves to
gather information about Earth’s interior.
• By studying how earthquake waves
move, scientists are able to infer the
density and composition of the materials
within Earth.
Temperature and pressure increase as depth
increases inside Earth.
Earth’s 4 Layers
The Earth is composed of four different
layers.
• crust
• Mantle
• outer core
• inner core
The Crust
• The brittle, rocky, outer layer of
Earth is called the crust.
• It is the least dense and thinnest
layer
• The Earth's Crust is like the
skin of an apple- very thin.
• The crust is only about 3-5
miles (8 kilometers) thick under
the oceans (oceanic crust)
• and about 25 miles (32
kilometers) thick under the
continents (continental crust).
• The crust under oceans is called oceanic
crust and is made of dense rocks containing
iron and magnesium.
• Continental crust is much thicker and less
dense.
The Mantle
• Earth’s mantle is the thick
middle layer.
• Scientists group the crust
and the uppermost mantle
into a rigid layer called the
lithosphere.
• The layer of rocks within
the mantle, where the rock
is soft enough to flow, is
called the asthenosphere.
• The solid rock below the
asthenosphere, where high
pressure prevents melting,
is the mantle.
Lesson 2-2
The Core
• The dense metallic
center of Earth is
the core.
• The outer core is
liquid iron and nickel and the
inner core is solid iron.
Bellwork: 10/13
• Describe each layer on your green bellwork sheet:
• Crust: ____________________________________
• Mantle: ___________________________________
• Outer Core: ________________________________
• Inner Core: _________________________________
Vocab Quiz over the 10 yellow terms
tomorrow. Quiz over white terms on
Monday.
1.
2.
3.
4.
5.
6.
Inner Core
Outer core
Mantle
Crust
Lithosphere
Asthenosphere
7. Earth layers
8. Chemical Composition
9. Physical Properties
10. Density
11. Gravity
14. Temperature
15. State of Matter
16. Pressure
17. Magnetosphere
18. Plasticity
Earth’s Core and Geomagnetism
• For centuries, people have used
compasses and Earth’s magnetic field to
navigate.
• Earth’s magnetic field is a region of
magnetism produced in part by the flow of
molten materials in the outer core.
• The magnetic field acts like a giant magnet
with opposite poles.
The outer part of the
magnetic field that
interacts with cosmic
rays and charged
particles from the Sun
is called the
magnetosphere.
Foldable: Earth Layers
10/14
1. Cut out circle 1, making sure to leave the flaps on either
side attached.
2. Cut out the other 4 circles.
3.
4.
5.
6.
7.
8.
Lay circle 5 flat on the table.
Lay circle 4 on top of circle 5.
Lay circle 3 on top of circle 4.
Lay circle 2 on top of circle 3.
Fold circles 2-5 in half down the middle.
Cut circle 1 down the middle on the dotted line.
9. Glue circle 5 into the center page of your INB.
10. Glue the left half of each circle to the circle below it
(except for circle 1).
11. Fold the flaps on circle 1.
12. Place circle one on top of all circles and glue down the
flaps onto the notebook paper so circle one opens like
shutters.
13. Open the foldable.
14. Trace the outline of circle 2 onto the right side of circle 3.
15. Fold back circle 2. On the inside, write “The Inner Core”
at the top. You will fill the rest of the space with
information about the inner core.
16. Trace the outline of circle 3 onto the right side of circle 4.
17. Fold back circle 3. On the inside, write “The Outer Core”
at the top. You will fill the rest of the space with
information about the outer core.
16. Fold back circle 4. On the blank left side, write “The
Mantle” at the top. Draw an arrow from “The Mantle” to
the second layer on the right side of the foldable.
17. Half way down on the left side, write “The Crust”. Draw a
line
18. You will fill the rest of the space on the top of the left with
information about the mantle an the bottom with
information about the crust.