The Rock Cycle

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The Rock Cycle
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Minerals

• A natural occurring solid with a crystalline
  structure.
• Nonliving.
• Quartz, diamond, and salts are all minerals.
• Used in jewelry.

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Mineral Properties

• Color Minerals come in a rainbow of colors.
• Streak The color of the powder left behind when
  you rub a mineral against a rough white tile. It
  does not vary.
• Luster The way a mineral reflects light. Many
  minerals have a metallic luster.

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Mineral Hardness

• A minerals ability to resist being scratched.
• Some minerals can not be scratched by anything.
• The softest mineral is talc and is classified by
  a 1.
• The hardest minerals are diamonds and they are
  classified by a 10.

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Detecting Hardness

• Hardness is determined using the Mohs scale.
• The scale goes from 1 to 10. Any mineral that is
  higher on the scale can scratch any mineral lower
  on the scale.

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Example

• Suppose you have a mineral whose hardness is
  unknown.
• A steel nail (hardness of 5.5) can not scratch
  the mineral, but a piece of quartz (hardness of
  7) can. What is the hardness of this mineral?

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Answer

• Suppose you have a mineral whose hardness is
  unknown.
• A steel nail (hardness of 5.5) can not scratch
  the mineral, but a piece of quartz (hardness of
  7) can. What is the hardness of this mineral?

• The mineral has a hardness between 5.5 and 7
  since a steel nail could not scratch it but a
  quartz could.

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Special Properties

• Magnetism
• Fluorescence
• An Electrical Charge
• Produces a double image

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Rocks

• A natural solid made of one or more minerals.
• Mountains, valleys, hills, beaches, and the ocean
  floor are made of rocks.

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Igneous Rocks

• Rock that forms when melted rock cools and
  hardens.
• Can form underground or on the Earths surface.
• When formed underground igneous rocks have large
  crystals.
• When formed on Earths surface they have small or
  no crystals.

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Sedimentary Rocks

• Pieces of sediment that have been pressed and
  cemented together.
• Pieces of sediment settle out of water or wind
  during deposition. This leads to the formation of
  sedimentary rocks.
• Forms from any worn down rock.

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Metamorphic Rocks

• Rock changed by heat and pressure.
• Can form from any other rock.
• Found in every mountain range on Earth.
• Found in the ocean and near some volcanoes.

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ExamplesDraw a line to match.

• Igneous Rocks
• Sedimentary Rocks
• Metamorphic Rocks

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How Rocks are Used

• A natural resource.
• Sandpaper.
• Buildings.
• Monuments.
• The US Capitol building uses sandstone and marble.

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Processes that Change Rocks

• Weathering is a process of breaking down rocks
  into sediment.
• All rocks on the Earths surface are weathered.
  Wind and water also weathers rocks.
• The process of wearing away and removing sediment
  by wind, water, or ice is called erosion.

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The Rock Cycle

• A continuous process in which one type of rock
  changes into another.
• Weathering, erosion, deposition, heat, and
  pressure can all change rocks.

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Science Up Close

• Earth recycles rocks through the rock cycle.
• Heat and pressure can change one type of rock to
  another.

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Soil Formation

• Soil can be formed from weathered rock under it
  or from eroded sediment carried from far away.
• Soil contains minerals.
• Most soil is made up of more than just weathered
  rock.
• Farm soil contains small pieces of decayed plants
  and animals called humus.

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Summary

• The Rock Cycle is a group of changes. Igneous
  rock can change into sedimentary rock or into
  metamorphic rock. Sedimentary rock can change
  into metamorphic rock or into igneous rock.
  Metamorphic rock can change into igneous or
  sedimentary rock.

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Video
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Questions

• What are minerals?
• What are three visible properties of minerals?
• How can you determine a minerals hardness?
• How do rocks form?
• How are rocks changed?