Download How are rocks formed?

ROCK CYCLE
SEPT. 26
Falcon Focus
Explain how
Triangulation
works
Essential Question
•HOW ARE ROCKS
FORMED?
Review
•Let’s See What You
Know!!!!!
• Boundaries, Stresses, and Faults
Plate
Movement
(Arrow)
Boundary
Stresses/F
orces
Fault
Plate
Movement
Forms
*
FF: Which Seismic wave do not pass through
the outer core?
When you find the distance from the epicenter for 3
stations, you can pinpoint the epicenter. You draw a
circle from each station with a radius that is the
distance to the epicenter for each station. Where the
3 circles intersect is the epicenter.
Triangulation
of 3 stations
to locate
earthquake
epicenter
Magnitude
How do Fold Mountains form?
Explanation of fold mountains
Use the following two resources
to help you explain how fold
mountains are formed
Fold Mountains
FALCON FOCUS- SEPT. 27
Define the following:
• Weathering
• Erosion
• Deposition
ESSENTIAL QUESTIONSEPT. 27
What processes form
igneous,
sedimentary, and
metamorphic rock?
FALCON FOCUS-SEPT. 28
Name the 3 rock types and how
they form.
ESSENTIAL QUESTIONSEPT. 28
Explain how an igneous rock can
be turned into a metamorphic rock,
then a sedimentary rock and back
to an igneous rock over time.
Rock Cycle animation
• Go to http://dms.dcsdschools.org/home
• Click on “Departments” in the top purple
tab
• On the dropdown menu, go to Science
• Click on Nicole Grant -8th Grade Science
• Click on “Grant’s Lessons” on the right
hand side
• Click on “Rock Cycle” for an animation
Performance Indicator:
8.E.5A.2 Use the rock cycle model to
describe the relationship between the
processes and forces that create
igneous, sedimentary, and metamorphic
rocks.
Standard/Objective:
Standard 8.E.5
STUDENTS SHOULD BE ABLE
TO: use the rock cycle model to
describe how different processes
create different rock types.
Rocks
• Rocks are naturally occurring
combinations of minerals.
• Most consist of two or more different
minerals.
• Rocks are classified according to how
they were formed.
Physical Properties of Rocks
1. Color (may have a distinctive color for
identification)
2. Streak (is the color of the mineral in powdered
form- shows the true color of the mineral)
3. Hardness (is a measure of the mineral’s
resistance to scratching)
4. Luster (property of minerals that indicates how
much the surface of a mineral reflects light or
if it is SHINY.)
How do Rocks form?
• How much time does it take to form a
rock?
– If you squeeze and heat a rock for a
few million years, it can turn into a
new kind of rock.
ROCKS
• There are three large classifications of
rocks – igneous, metamorphic, and
sedimentary. Each type of rock is
formed differently and can change from
one type to another over time. The way
rocks are formed determines how we
classify them.
3 TYPES OF ROCKS
• IGNEOUS EXAMPLES:
Granite, Obsidian, Pumice
• SEDIMENTARY EXAMPLES:
Sandstone, Limestone, Shale
• METAMORPHIC EXAMPLES:
Slate, Marble, Gneiss
3 types of Rocks
Types of Rocks
Igneous
Sedimentary
Metamorphic
Examples…
Igneous
Metamorphic Sedimentary
Granite
Slate
Sandstone
Obsidian
Marble
Limestone
Pumice
Gneiss
Shale
IGNEOUS ROCK
Igneous Rocks (Volcanoes)
• Igneous – means “fire formed.”
• IGNEOUS ROCKS: Forms when molten
rock (magma or lava) cools and hardens
. (MOLTEN ROCK)
– Think of candle wax cooling
– Igneous Rocks forms NEAR OR around
VOLCANOES…
2 types of Igneous Rocks
• When lava is cooled it forms a rock.
• When magma cools within the Earth, it
also forms rocks.
• What’s the difference between lava and
magma?
Igneous Rocks (Volcanoes)
• Extrusive rock – Igneous rock formed from lava
that erupted from a volcano. (exterior – exit)
– Examples: Basalt,
Obsidian
• Extrusive: Small crystals – Cools Quickly
Igneous Rocks (Volcanoes)
• Intrusive rock – Igneous rock that formed when
magma hardened beneath or inside a
volcano. (interior – inside)
• Rocks cool slowly
– Example: Granite
Intrusive: Large crystals – Cools
Slowly
WHAT TYPE OF IGNEOUS ROCK FORMS
IGENOUS ROCKS PROCESSES
Igneous Rocks goes mainly through
processes:
• 1. Crystallization
• 2. Melting
• 3. Cooling
Review
1. From where do igneous rocks form?
2. The only way igneous rocks can form is from
the cooling of what?
3. What are the two types of igneous rocks?
Explain the difference between them.
4. What are the 3 processes igneous rocks go
through?
5. Explain how large and small crystals form in
igneous rocks.
SEDIMENTARY ROCK
Sedimentary Rocks
• Forms near bodies of water or
where bodies of water use to be
• Sedimentary rocks are made up
of sediments.
What are Sediments?
• Sediment are small, solid pieces of
rock, mineral grains, or shell
fragments
• Sediments are formed through the
processes of weathering and
erosion of rocks exposed at Earth’s
surface.
• Sedimentary rocks can also form from the
chemical depositing of materials that
were once dissolved in water.
(DEPOSITION)
• THEREFORE, SEDIMENTARY ROCKS
Forms from the compaction and/or
cementation of rock pieces, mineral
grains, or shell fragments called
sediments.
Two Processes that make
Sedimentary Rocks
• 1. Compaction - process that presses
sediments together.
– At first, the sediment fits together loosely.
Over long periods of time the layers build up.
– The layers are heavy and press down on
each other.
• 2. Cementation – process in which
dissolved minerals crystallize and glue
sediment together.
Sedimentary Rocks
• Sedimentary rocks usually have
fossils within them.
• Sedimentary rocks are also
known for having layers.
Review Questions
• What does sedimentary rocks from?
• What are the two processes that
sedimentary rocks go through?
• How do sedimentary rocks form?
• What are sediments?
• How do sediments form?
METAMORPHIC ROCKS
Metamorphic Rocks
• Metamorphic rocks form underneath the
Earth’s Surface.
• Forms when rocks are changed into
different kinds of rocks by great heat
and/or pressure
• Metamorphic rocks are heated,
squeezed, folded, or chemically
changed by contact with hot fluids.
(THIS ROCK GOES THROUGH
CHEMICAL CHANGES)
• When heat and
pressure reach the
rock’s melting point, it
melts into magma.
Metamorphic Rocks
Processes
• Metamorphic goes through 2
processes:
• 1. Heat
• 2. Pressure
Metamorphic Rocks
Classification
Classified by the arrangement of the grains
that make up the rocks.
• Foliated Rocks – Have obvious layers.
• Non-Foliated Rocks – Have no visible
layers.
Foliated or nonfoliated?
Granite (igneous) = GNEISS (metamorphic)
Limestone (sedimentary) = MARBLE (metamorphic)
Shale (sedimentary) = SLATE (metamorphic)
ALL ROCKS
• What Process Do All Rocks
Go Through????
• Weathering, Erosion, &
DEPOSITON
RC (Review Check)
• Types of Rocks
RC (Types of Rocks Questions)
•
•
•
•
•
•
•
•
•
1. Forms underneath the Earth’s surface
2. Forms around volcanoes
3. Forms near bodies of water or where bodies of water use to be
4. Have fossils within them
5. Goes through the process of cooling, melting, and crystallization
6. Goes through the process of heat and pressure
7. Goes through the process of compaction and cementation
8. Consist of Intrusive and extrusive rocks
9. Can change into other rocks, can be foliated and go through
chemical changes
• 10. Can go through the process weathering and erosion
THE ROCK CYCLE
• The rock cycle is an ongoing process.
The sample diagram illustrates the series
of natural processes that can change
rocks from one kind to another:
• The rock cycle is an example of how
Earth recycles itself.
CLOSURE/
WHAT TYPE OF ROCK?
•
•
•
•
•
•
Basalt
Slate
Granite
Limestone
Scoria
Marble
Gneiss
Falcon Focus
• What are the processes that each rock
goes through? What process do all rocks
go through?
Essential Questions
• How would you explain how the three
types of rocks form and where do they
form?