Earth Surface changes

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Earth Surface changes

• Changes to Earths surface happen over time.
• Some changes are due cataclysmic events like
  volcanoes erupting, or earthquakes.
• These changes are fast and violent.

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Slow changes

• Other forces change Earth slowly.
• The suns energy drives wind, water, temperature
  changes, and life forms that can change the
  Earth.
• Slow changes are called weathering.

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Physical Weathering

• The Earths surface is made of rock and soil.
• Rocks form from different processes.

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Minerals

• Rocks are made of minerals.
• Minerals are elements that have been combined
  together by chemical reactions.
• Some minerals are pure like gold and some
  minerals are combinations like salt.

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Properties

• Minerals have different physical properties.
• Color
• Luster
• Hardness
• Streak
• Cleavage

mineral id 948
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Mohs Hardness Scale

• A way to identify minerals is to use the scratch
  test and identify the mineral with a scale.
• What other ways could you use to identify
  minerals?

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Rocks

• Minerals combine to form rocks. Scientists
  classify rocks according to how they are formed.

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Igneous Rocks

• When magma cools igneous rocks form.
• You can identify igneous rocks by the crystals or
  holes formed by gas bubbles.
• Most dark colored rocks are igneous.

obsidian
Pumice
granite
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Sedimentary

• Formed by sediments.
• Sediments are pressed and cemented together.
• May contain fossils.

sandstone
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Metamorphic

• Rocks that are pushed underground deep into the
  crust can be heated again.
• Sedimentary and igneous rocks that are reheated
  can change into igneous rocks.
• Look for ribbonlike layers.

gneiss
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Rock Cycle

• Rocks can go from one type to another by the rock
  cycle.

Rock cycle
rock cycle vid
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Rock cycle
geology kitchen
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Rock cycle
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Weathering by water

• Water causes weathering by
• Freezing and cracking rocks
• Water in rivers and streams makes rocks in the
  water move. Rocks break into smaller pieces.
• Water carries sand or pebbles that will rub
  against rocks and wear them down.

rock weathering video
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Weathering by wind

• Wind picks up sand and blows the sand against
  rock.
• The wind wears down the rock and changes the rock.

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Living things

• Roots and plants grow in cracks in rocks and
  widen cracks in the rock and break them up.

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Chemical Weathering

• Rainwater and groundwater join with carbon
  dioxide gas from the air to form a weak acid.
• The acid wears away the rock.
• Forms caves over time.
• Caves form in sedimentary rock (limestone)

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Soil

• Soil is made of layers.
• The layers are different from other layers.
• Undecayed (humus)
• Topsoil loose rich soil, holds lots of humus and
  minerals. Good for plants.
• Subsoil Holds many minerals, where you find
  clay.
• Rock Weathered rock and bedrock

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Layers of the Soil
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Running Water

• Gravity makes the water move. Loose soil gets
  pulled in the water.
• The draining water is called runoff. Runoff
  carries soil, sand, and small rocks.
• The runoff deposits sediments at the bottom of
  the river, this is called deposition.

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Waves

• Waves pound on the shore.
• Energy in the wave break up rocks into smaller
  rocks.
• Change rough rocks to smooth rocks.
• The wave action will erode away the shoreline.
• Makes haystacks on the Washington and Oregon
  coast.

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Gravity and Mass movement

• Gravity pulls large masses down mountains and
  hills.
• This mass movement in the mountains are called
  avalanches.
• The mass movement in hills are called landslides
  or mudslides.
• Can happen fast like a mudflow or slow with creep.

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Groundwater

• When rain falls or ice melts some of the water
  goes into the ground.
• Water will mix with CO2 to form a weak acid that
  weathers the limestone.
• Water will seep into tiny holes in the rocks.
• Groundwater will form caves.
• Water evaporates leaving minerals that build
  stalagmites and stalagtites.

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Wind

• Strong winds pick up sand, and small pebbles.
• These winds can weather rock. Rocks will break
  into smaller rocks.
• Erosion happens when these smaller rocks and sand
  move from the power of the wind.
• When winds slow down, the sand and dirt is
  deposited in a new place.
• The Dust bowl happened when there was a lot of
  wind blowing dust. The topsoil needed to grow
  food was deposited hundreds of miles away.

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Glaciers

• Large masses of water that are on mountains.
• We depend on glaciers for our water and
  electricity.
• Glaciers move slowly because of gravity.
• Glaciers push snow, sands, and rocks ahead of it
  called glacial till.
• Valley glaciers carve out the valleys on
  mountains.
• Glaciers cover 10 of the Earths land.

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Weathering and Erosion

• What is the difference?

Bill Nye
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What formed the Grand Canyon?
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river formations
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Fossils

• Form in sedimentary rock.
• We use fossils to learn about the past. Some
  fossils have been dated to be hundreds of
  millions years old.
• Fossils give us clues about Earths history.

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Trace fossils

• Tell us how and where an organism lived.
• Tracks, burrows, nests, animal waste, tooth marks
  are all trace fossils.

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Body Fossils

• Show us what the plant or animal looked like.
• Petrified fossils minerals in groundwater seep
  into the remains and harden.
• Most dinosaur fossils are body fossils.

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Mold Fossils

• Plants or animals are covered by sediments.
• Sediments harden and turn into rock.
• Groundwater dissolves the organism.
• A hollow space is left.

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Amber fossils

• Insects become trapped in tree sap.
• Insects are preserved when the sap hardens into
  amber.

dino dna
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Erosion Jigsaw

• Each group will be assigned a reading section in
  the Erosion delta reader.
• Each member needs to read the section and take
  notes in their journal.
• Once all notes are taken, the group will design a
  poster that highlights the most important
  information. (The poster has to have words and
  pictures on it. Font needs to be Word Wall size.
• Reporter and a partner will present to the class.
• Class will take notes.

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Groups

• Group 1 Running water pg. 9
• Group 2 Waves pg. 10
• Group 3 Gravity and mass movement pg 11
• Group 4 Groundwater (12)
• Group 5 Wind (12-13)
• Group 6 Glaciers (Glaciers)

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What formed the Grand Canyon?

• Claim Scientists believe that the grand canyon
  was formed from the Colorado River.
• Evidence Use evidence from your lab to explain
  how they could come to that conclusion.
• Possible Evidence
• Draw picture
• Use vocab from the landforms sheet

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Weathering and Erosion Wrap up