Transcript 5th Grade – chapter 9

5th Grade Earth
Science
Chapter 9
Earth’s Changing Surface
What is the Earth made of?
• Landforms on Earth include:
–
–
–
–
–
Mountains
__________
__________
- flat land
Plateaus
________
Gorges - a deep crack
Plains - flatlands with few trees
______
valleys - on land where mountains are close
_______
together
– ______
Ridges - beneath the ocean, long row of towering
mountains
– ________
Trenches - long narrow canyons in the ocean floor
Earth’s Layers
• The Earth is composed of three distinct layers:
Crust
1. ______
- outermost solid layer of the Earth.
-
The part of the Earth where life is sustained
This layer includes _____and
_____
soil
rock that covers the
surface
ocean and dry _______
land
The crust is covered by _______
The thickness of the Earth’s crust varies
Earth’s Crust
The Mantle
Mantle
• 2. The _______
- is the layer of Earth just
below the Earth’s crust.
mass
– This layer contains most of the Earth’s _______
the amount of matter in an object
– The outer part of the mantle closes to the crust is
solid
_____
– The inner part of the mantle furthest from the
crust is made of rock that is so hot that it can
flow very slowly.
_____
Structure of the Earth
The Core
core - the innermost layer of the
• 3. The ____
Earth. The core is made primarily of ______.
iron
– This layer is most compact because of all of the
weight above it
– The core is divided into two distinct parts:
• ___________
Outer core - located closest to the mantle. This layer
is so hot that it is liquid
Inner Core - located furthest from the mantle and
• ___________
crust – this layer is solid
Layers of the Earth
Section Assessment
• Page 265 questions 1-3
Earth’s Plates
lithosphere
• _________
- the Earth’s crust and the upper
part of the mantle.
– The lithosphere is not a continuous layer it is
Tectonic plates
made up of pieces called ______________.
– The tectonic plates are of varying shapes and sizes
but they all fit together like a puzzle.
– Much of the Earth’s lithosphere is under ________
oceans
and other bodies of water.
10 major tectonic plates
– There are ____
Tectonic Plates
Spreading Ocean Floor
Mid-Atlantic Ridge - chain of mountains running
• ____________
along the floor of the Atlantic ocean.
Henry Hess
• ____________
- A scientist in 1960 claimed
that new crust forms at ocean ridges – this
explains the existence of trenches and ridges.
• ________
- molten rock, pushes upward from
magma
the Earth’s crust. As the magma cools it forms
new crust.
What causes Magma to rise?
• As Earth plates move away from each other,
the ocean floor spreads apart and new crust
rises to fill the gaps.
• What causes the plates to move apart?
• __________
Arthur Holmes - 1930’s when a liquid is heated,
particles speed up and move apart.
– ___________
weigh less and float above
Hot liquids
Cooler liquids
____________.
Convection
• _________
convection - as the hot liquid rises and cools it
becomes heavier again and sinks, more hot liquid
can rise above again – transfer of thermal energy
by the movement of a liquid or gas.
mantle
• Currents in the ________
constantly rise from the
slow flow of the molten rock, circle around and
then fall.
• Convection is the force
_______ that moves the Earth’s
plates.
Theory of Plate Tectonics
Theory of Plate Tectonics - the _________
lithosphere is broken
• ________________
into 20 moving plates.
– Plates in constant motion and in different
directions.
– ____________________
Global Positioning System - (GPS) satellites in
space - determine the distance between plates
and their change over time.
– This theory explains many of Earth’s features
Moving Continents
• Continents move apart
• Mountains form where plates move together
• As plates move apart, magma may rise to the
volcano
surface forming a ________
• Oceans may become larger or smaller
• Positions of land and oceans has changed and
continues to change from the time of
Pangea
_________
to the __________.
Continents
Plate Boundaries
Plate Boundaries
• _____________
- areas where two plates
meet.
Spreading boundaries - plates move away from
– _________________
each other
• gaps form between the plates
• __________________
Convection currents cause magma to rise between
the gaps
• Huge valleys
________ form
Mid-Atlantic Ridge
• Sea floor spreading – ex. _____________________
Plate boundaries continued
• ______________
Fracture boundaries - plates slide past each other
• _____break in the Earth’s crust as a result of
fault
fracture boundaries – this can cause
earthquakes
_________.
Colliding Boundaries - two plates push against
• ______________
each other – one plate might slide underneath
the other – towering mountains, deep ocean
trenches, earthquakes, and volcanoes can
result.
Boundaries and GPS
Earthquakes
Earthquakes are caused by the sudden shifting
• _________
of rock as tectonic plates shift positions
– Pressure builds up, rocks lurch forward, and the
Earth’s crust shakes.
– ______
focus - the underground point where the
earthquake occurs
epicenter - point on the Earth’s surface directly
– ________
above the focus.
Waves
• Energy from the earthquake is carried by
_______.
waves
focus and
• Waves spread out from the _____
________.
Volcanoes
• Waves can cause the Earth to move ________,
Up and down
___________,
or in a ___________
Back and forth
Circular motion
• As the waves spread out from the epicenter,
they __________.
Lose energy
Earthquakes and Plate boundaries
California
Alaska
• ____________
and _________
have had the
most earthquakes because they are located on
Plate Boundary between the Pacific plate and
a ____________
the North American Plate.
• The strength of an earthquake can be
measured on a ____________
Magnitude scale - a series of
numbers that is based on the amount of
energy that is released.
S and P waves
• http://www.thetech.org/exhibits/online/quak
es/waves/p&s_waves.html
Draw a diagram of each
Volcanoes
• __________
occur when magma from the
Volcanoes
mantle either flows or explodes through the
crust.
– Opening in the surface of the Earth through which
magma rises
– Occur near ______________
Plate boundaries
– Theory of plate tectonics – one plate sinks
beneath another at a plate boundary – sinking
crust melts into _______.
magma
lava - Magma that reaches the surface
– _____
Draw and Label Volcanoe page 270271
Earth’s Features
• Earth’s surface is made up of many different
__________.
Landforms
• Earth’s surface is constantly ________
and so
changing
are the landforms
weathering
• ___________
- the process of breaking down
rock into smaller pieces
• Forces of __________
include ________
and
weathering
water
_____
ice
Mechanical / Chemical Weathering
• _________________
- process of breaking
Mechanical Weathering
down rock into smaller pieces as a result of ice
or water – MINERALS THAT MAKE UP THE
ROCK DO NOT CHANGE!
• ________________
- minerals that make up
Chemical Weathering
the rock change.
• The cause of chemical weathering is a
_________
with something in the
reaction
water or ________
oxygen
environment such as ____
Erosion
erosion
• ________
- the process by which soil and
sediments are transferred from one location
to another
• The movement of soil and sediments can be
caused by:
– _________
wind
– ________
water
– ______
ice
– ________
gravity
Soil Erosion
• Areas of land with no plant covering are
Soil erosion
susceptible to __________
• __________
- help prevent soil erosion by
Plant roots
holding the soil in place
Cover crops
• ___________
- planted by farmers in between
harvests to prevent soil erosion and add
nutrients to the soil
• ______________
Dust Bowl of 1930’s - years of drought and poor
farming practices left bare areas of soil
Soil
soil - made of weathered rock, air, water, and
• ____
the remains of living things.
weathering
• __________
- process of breaking down rocks
through physical factors such as _____,
frost
drought
rainwater or__________________.
Changes in temperature
_________,
_______
• ________
= non-living parts of the soil
inorganic
• As rock breaks down small pieces collect on
the surface
Soil Formation
• _______
and _______
are plants that help
mosses
lichens
break down rock.
• When rocks are broken down minerals
_______are
released
• ___________
- dead or decaying matter such
Organic matter
as bacteria, fungi, animals and plants.
humus
• ______
- dark colored organic matter
formed from decayed plant and animal
Rich in nutrients needed by plants
remains- _______________________
Layers of Soil
• Soils form in _____
three layers
• _________a vertical cross section of the soil
Soil profile
and rock underneath
• ________
- first layer of soil, mixture of small
topsoil
rock pieces, humus, and other organic matter
– Most living things are found in the _______
topsoil
– Loose _____________
Organic matter often covers the topsoil
– Rainwater carries minerals from the topsoil to the
2nd layer of soil.
Subsoil / Parent Rock Layers
subsoil
• _______
- less organic matter than topsoil,
lighter in color.
mineral
• _________
penetrate the subsoil through
rainwater and accumulate
Parent rock - third layer, very little organic
• _________
matter found in this layer
Water
• _________
- solid particles that are moved from
sediments
one place to another
deposition
__________
- sediments that form during
weathering and erosion are deposited in another
location
During the process of deposition, the _______
and
shape
direction of a river’s flow changes
________
As rivers flow to the oceans they carry ________
sediments
Dissolved minerals which are useful to plants
and ______________
and animals to carry out their __________
Life processes
River Systems
Dynamic systems
• Rivers and streams are _____________
always moving and changing
• _______
Stream - begins on land that is higher than
sea level – ______
gravity pulls the water downward
to a lower area
• _____
river - streams join until a river is formed
• River water wears down soil and rock and
carries their ________
sediments away in different places
Wave Energy
Pass along
• Ocean waves ________
and __________
a
carry
great deal of _________
energy
• Water _______
and _______
in a circular
rises
falls
motion
• __________
contained in the waves moves
energy
forward
• _________________
Shallower ocean bottom interferes with the
waves movements – causes waves to slow
Waves continued
• Wind Waves are formed when energy is
transferred from the ________
to the _______
wind
water
• ____________
depends on the _________
Size of waves
Wind speed
and how __________
Long it blows and _____________
Distance it covers
• Waves can also be caused by:
– ______________
tectonic activity
Volcanic eruptions
– _______________
– ______________________
Earthquakes and landslides
Dynamic Systems
• __________
are dynamic systems because the
beaches
energy from waves has the power to
• _________
also build up beaches by moving
waves
sand along the shore
sandbar
• _________
created when waves move
materials from the shoreline to an area away
from the shore
• __________
- places where water bodies are
lagoons
separated from the open ocean
Beaches
• ________
formed when wind carries sand
dunes
along the shore - sand builds up into small
hills
• ______________are
constantly changing as a
Coastal Landforms
result of wind
________ and ______
water
• _____
of any beach is
Color and ________
texture
sand
determined by the sources of its ______
and
_____
- no two beaches are the same!
rock
Section Assessment
• Question 1 on page 278
Section Assessment
• Questions 1-3 page 281
Minerals
• ___________
- a natural, non-living solid with
Mineral
a definite chemical structure.
4,000 kinds
• Earth’s crust contains more than _________
minerals – only two dozen are common.
• Examples: diamond, quartz, emerald copper
crystals
• Minerals are made up of ______.
• Particles of _______
are arranged in a
crystals
particular repeating pattern.
Crystals
Mineral
• _______
form when minerals are made in
nature
• Each type of mineral has its own unique
chemical __________.
structure
• Differences in minerals result from the way
that particles are arranged.
• Brass – Copper + Zinc –____________because
Not a mineral
it does not occur naturally
Identifying Minerals
characteristics
• Minerals are identified by their ____________
• _______________
Moh’s hardness scale - a scale to measure
hardness of a mineral
• The range of the harness scale is from 1
Softest
Hardest
(_______)
to 10 (______)
1 / diamond is a _____
10
• Talc has a harness of __
• ________
- refers to how difficult it is to
hardness
scratch its surface
Other Mineral Characteristics
• _______
- a mineral may have different
Color
crystals depending on the kinds of materials
crystals
that make up its ______.
• The color of a mineral can be seen in its
______.
streak
• A mineral can also be identified by the ______
shape
of its crystals.
• _______
Cleavage - minerals show particular patterns
when they are broken along flat planes.
Luster
• ______
Luster - the appearance of a mineral in
reflected light.
• A mineral may appear:
Metallic
– __________
– __________
Nonmetallic
Greasy
– __________
Glassy
– __________
Waxy
– __________
Rocks
• _____
- a solid, natural material made up of
rock
one or more minerals
Rock cycle
• ___________
- as time passes, rock break
down, and the minerals in them are recycled –
pattern of change
• The rock cycle takes place over millions
________ of
years.
• There are three types of rocks: __________,
sedimentary
__________,
and __________
igneous
metamorphic
Sedimentary Rock
• ______________
- made from pieces of rocks
Sedimentary rock
and minerals
layers
• Sedimentary rock forms in ________
- the
oldest rock at the bottom and the newest rock
on top.
• Sedimentary rock is like a “_________”
- past
History book
events captured in each layer.
• _____
fossils - remains of once living animals or
plants
Sedimentary Rock Continued
Sedimentary rock
• Fossils are ONLY found in _____________
• Example of sedimentary rock = ________
limestone
• Limestone is made from _________________
Shells of tiny sea animals
or from dissolved __________
that settle out
minerals
of seawater.
Igneous Rock
• __________
Igneous rock - forms from magma – molten
rock inside of the earth that cools and hardens
Earth’s surface
• Some igneous rock forms Below
______________
and is only exposed after rocks above have
worn away
• Other igneous rocks form when lava
_____ cools at
the Earth’s surface
• When lava cools fast - _______________
Fine-ground rocks form
• When lava cools slowly - _______________
Coarse-grained rock
Metamorphic Rock
Metamorphic rock - forms when heat, pressure,
• _____________
or chemical reactions change one type of rock
into another type of rock.
• Metamorphic rock is made from ___________
Sedimentary rock
Igneous rock
or _________.
• Example: ______
marble is a metamorphic rock made
limestone (sedimentary rock)
from________
Compare and Contrast
• How are the three types of rocks similar and
different?
Clues to the Past
• Scientists can tell a great deal about Earth’s
history by looking at _____.
rocks
Relative dating
• ______________
- scientists look at the layers
of sedimentary rock and learn about the
relative age of each layer and the minerals
found in it.
• Relative dating allows scientists to place past
events in ____________
Sequential order
Rock Cycle