Cycling of Rocks

Cycling of Rocks

Middle School

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Learning Objectives

• Model the rock cycle, including melting, crystallization, weathering, and sedimentation processes.

• Explain how energy from the sun and Earth’s interior drives the rock cycle.

• Identify the three main rock types and describe how they are formed.

• Connect energy flow and matter cycling to changes in rocks over geologic time.

Key Vocabulary

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Rock Cycle

The model that describes how rocks change from one type to another over a long period.

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Weathering

The breakdown of rock at the Earth’s surface by physical or chemical means like wind or rain.

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Erosion

The movement of weathered rock and soil from one place to another by natural forces like water.

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Sedimentation

The deposition of sediment in a new location, which often results in the formation of new layers.

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Igneous Rock

A type of rock that is formed from the cooling and crystallization of molten rock or magma.

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Sedimentary Rock

A type of rock that is formed from compacted and cemented sediment that builds up over time.

Key Vocabulary

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Metamorphic Rock

A type of rock that has been changed by extreme heat, pressure, or chemical reactions.

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Melting

This is the process that completely changes solid rock into hot liquid rock called magma.

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Crystallization

The process where atoms in cooling magma arrange themselves to form an organized crystal structure.

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Deformation

The alteration of a rock's original size or shape due to different forms of stress.

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Magma

Hot, molten rock material found beneath the Earth's surface from which igneous rock is formed.

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Plate Tectonics

The scientific theory describing how Earth's large continental plates move and glide over the mantle.

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The Rock Cycle: A Model of Matter and Energy

• The rock cycle is a model showing how matter cycles on Earth.

• This cycle slowly transforms rocks from one type into another over time.

• Energy from the sun and Earth’s interior drives all these changes.

• These changes happen over geologic time, which is millions of years.

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Multiple Choice

What does the rock cycle model illustrate?

• How matter cycles and transforms into different rock types on Earth.

• How energy from the sun is captured and stored in rocks.

• How geologic time is measured in millions of years.

• How the Earth's interior produces heat and light.

Multiple Choice

What is the relationship between the rock cycle and energy from the sun and Earth's interior?

• Energy from these sources provides the power for rock transformation.

• The rock cycle is the original source of all energy on Earth.

• These energy sources are created by the movement of rocks.

• Rocks can only be transformed during the daytime using solar energy.

Multiple Choice

Based on the principles of the rock cycle, what would be the most likely long-term effect if the energy from Earth's interior significantly decreased?

• The process of rock transformation would happen much more slowly or stop.

• The rock cycle would speed up and happen in a few years.

• The amount of matter on Earth would significantly decrease.

• The sun's energy would become the only force changing rocks.

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From Magma to Rock: The Creation of Igneous Rocks

• Heat from Earth's interior melts solid rock, creating a liquid called magma.

• As magma cools, its atoms arrange into an orderly, solid structure called crystals.

• This process of melting and crystallization is what forms new igneous rocks.

• How fast the magma cools determines how large the rock's crystals will be.

Multiple Choice

What is crystallization?

• The process of forming solid crystals from a liquid

• The process of melting solid rock into magma

• The process of heat moving from the Earth's core

• The process of creating new igneous rocks

Multiple Choice

What is the relationship between melting and crystallization in the rock cycle?

• Melting creates hot magma, and crystallization turns that magma back into a solid.

• Melting cools magma down, and crystallization heats up solid rock.

• Both melting and crystallization are processes that create liquid magma.

• Both melting and crystallization are caused by the rapid cooling of rock.

Multiple Choice

If a body of magma cools very slowly, what is the most likely outcome for the resulting igneous rock?

• The rock will have very small crystals because it cooled slowly.

• The rock will have no crystals because it did not cool quickly enough.

• The rock will have large crystals because the atoms had a long time to form orderly patterns.

• The rock will be liquid magma because it did not cool at all.

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Internal Energy: Deformation & Metamorphism

Deformation

• Rock is bent, folded, or broken by immense pressure from inside the Earth.

• This process, called deformation, changes the original shape of the rock layer.

• It often occurs where tectonic plates collide, leading to the formation of mountains.

Metamorphism

• Intense heat and pressure cause minerals in a rock to change without melting.

• This physical and chemical transformation of rock is known as metamorphism.

• For example, sedimentary limestone can transform into the metamorphic rock marble.

Multiple Choice

What is the term for the process where immense pressure from inside the Earth bends, folds, or breaks rock, changing its original shape?

• Deformation

• Metamorphism

• Sedimentation

• Erosion

Multiple Choice

What is the primary difference between rock deformation and metamorphism?

• Deformation is caused by heat, while metamorphism is caused by pressure.

• Deformation melts the rock, while metamorphism only breaks it.

• Deformation changes a rock's shape, while metamorphism changes its mineral composition.

• Deformation creates new rock, while metamorphism destroys it.

Multiple Choice

Based on the processes described, what is the most likely outcome for a layer of limestone located where two tectonic plates are colliding?

• The limestone would likely be transformed into marble due to the intense pressure.

• The limestone would melt completely and become magma.

• The limestone would be broken down into sand and sediment.

• The limestone would remain unchanged but move to a new location.

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Solar Energy: Weathering, Erosion, and Sedimentation

• The sun’s energy is the main driver of weather on the Earth's surface.

• This weather causes weathering, which breaks down rocks into smaller pieces called sediment.

• Erosion is the process of moving this sediment by forces like wind or water.

• Sedimentation is when sediment settles, and over time, forms new sedimentary rock.

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Multiple Choice

What is the main source of energy that drives weather on the Earth's surface?

• The sun's energy

• The Earth's internal heat

• The gravitational pull of the moon

• The movement of tectonic plates

Multiple Choice

What is the relationship between weathering and erosion?

• Weathering breaks down rocks, and erosion moves the resulting sediment.

• Erosion breaks down rocks, and weathering moves the resulting sediment.

• Weathering and erosion are different words for the exact same process.

• Erosion forms new rock, and weathering causes it to settle.

Multiple Choice

Based on the relationship between solar energy and geological processes, what would be the most likely consequence if a planet received no energy from a sun?

• The processes of weathering and erosion would be greatly reduced.

• Rocks would break down into sediment much more quickly.

• Sedimentary rock would form at a much faster rate.

• The amount of sediment on the planet's surface would increase.

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Connecting The Processes: Plate Tectonics

• Plate tectonics connects all rock cycle processes, driven by Earth's internal heat.

• Convection currents in the mantle cause Earth's tectonic plates to move.

• Colliding plates form mountains, creating metamorphic rock through pressure and deformation.

• Subducting plates melt into magma, which cools to form new igneous rock.

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Multiple Choice

What is the primary energy source that drives the movement of Earth's tectonic plates?

• The internal heat from Earth's core and mantle

• The gravitational pull of the Moon

• The energy from the Sun warming the surface

• The force of strong ocean currents

Multiple Choice

How does the collision of tectonic plates contribute to the rock cycle?

• By creating intense pressure that changes the structure of existing rock

• By melting rock into magma which then cools and hardens

• By causing volcanoes to erupt and release lava

• By pushing ocean water onto the continents

Multiple Choice

If a tectonic plate is forced to subduct, or move underneath another plate, what is the most likely outcome for that plate material?

• The plate will melt into magma, which can form new igneous rock.

• The pressure will squeeze the plate into metamorphic rock.

• A large mountain range will be formed on the surface.

• The convection currents in the mantle will stop moving.

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Common Misconceptions

Misconception	Correction
Rocks are permanent and do not change.	The rock cycle is a continuous, very slow process that changes rocks.
The rock cycle follows a single, circular path.	It's a complex web where any rock can become any other rock type.
Rock formation happens quickly.	Rock formation and mountain building are very slow, taking millions of years.
Surface and interior processes are separate.	They are interconnected; internal energy drives processes that push rocks to the surface.

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Summary

• The rock cycle shows how energy and matter create three main rock types.

• Energy from the sun and Earth's interior drives the rock cycle's processes.

• Plate tectonics is a key process that connects internal and surface rock transformations.

• These changes happen over very long time scales, making Earth seem stable.

Poll

On a scale of 1-4, how confident are you about explaining the different pathways of the rock cycle?

• 1 (Not confident)

• 2 (A little confident)

• 3 (Mostly confident)

• 4 (Very confident)