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SCIENCE 6 TOPIC 4
Origami Shrimp
What is a model?
Is it this?
The model we’re interested in at this time is something
that represents the properties of another object.
A model can bring hard to comprehend terms like the
“earth” down to an understandable level.
Five types of models
1. Physical – such as a globe of Saturn
Five types of models
1. Physical – such as a globe of Saturn
2. Mechanical – a moving solar system
Five types of models
1. Physical – such as a globe of Saturn
2. Mechanical – a moving solar system
3. Mental – a drawing of electrons moving
around an atom
The
element,
Iodine
Five types of models
3. Mental – a drawing of electrons moving
around an atom
4. Mathematical – equations that help to
explain certain properties
V=L x W x H
Five types of models
5. Graphic – a chart showing air temperature
differences through the year
The three parts to the earth’s interior
The three parts to the earth’s interior
The solid crust
The three parts to the earth’s interior
The solid crust
Thick plasticlike mantle
The three parts to the earth’s interior
The solid crust
Thick plasticlike mantle
Liquid outer core
The three parts to the earth’s interior
The solid crust
Thick plasticlike mantle
Liquid outer core
The solid
inner core
How do scientists determine the
characteristics of earth’s interior?
H
I
N
T
Scientists determine the characteristics of earth’s
interior through earthquake wave analysis.
Earthquakes are caused by very large masses of rock
within the earth that move and rub against each other
Earthquakes are caused by very large masses of rock
within the earth that move and rub against each other
The San
Andreas
Fault is
one of the
most
famous
faults on
earth.
When the rocks rub up against each other they give
off waves of energy
When the rocks rub up against each other they give
off waves of energy
The focus
is the point
under the
earth’s
surface
where the
rocks
actually
moved in
the
earthquake
The
epicenter is
the point on
the earth’s
surface
directly
above the
focus point.
The two major waves of energy given off by an
earthquake are called
primary waves and secondary waves
Primary waves move fast and can travel through
solids, liquids, and gasses
Secondary waves move slow and can only travel
through solids and very, very dense liquids
With their knowledge of P and S waves scientists
can determine the characteristics and depth of
each layer of the earth
How do scientists do that? I’ll try to explain and you
try to follow along…
Plate Tectonics Theory
Plate Tectonics Theory
The
earth’s
crust
appears
to be
divided
into
many
different
sections
that
move.
Scientists use volcanic and earthquake data to draw the
conclusion that the earth is divided into these plates. At
the edge of the Pacific Ocean and South America is
where two plates are moving toward each other.
The mid-atlantic
ridge is one of
the famous
plate edges
where the
plates are
moving apart
from each other
– these are
called divergent
zones
What fault is this?
The San Andreas fault is an area where the two
plates are moving sideways to each other. A.K.A
Strike Slip Faults
The Himalaya Mountains are where it is believed
that two plates came together and both pushed up
– called convergent zones
Convergent Zones can also be where two plates
come together and one of the plates is pushed
under the other plate, into the mantle, and remelted
back into a thick, plastic-like material.
Scientists believe the plates move
by the process of convection
Some problems with the plate
tectonic theory
1. There are not enough subduction zones
to counter the expansion zones
The earth
could lose its
spherical
shape
Some problems with the plate
tectonic theory
2. “Scrapings” at the subduction zones are
nonexistant
Evidence of
accumulated sea
floor mud should
be found where
the plates meet
Some problems with the plate
tectonic theory
3. Convection in the earth’s interior poses a
problem – how would the convection
currents start?
Think: how is the experiment with your
beaker different from the interior of the earth?