Chapter 10: Weathering

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Chapter 10 Weathering Soil FormationSection
1 Weathering
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Section 1 Weathering
Chapter 10
Mechanical Weathering

• Mechanical Weathering is the breakdown of rock
  into smaller pieces by physical means.
• 1. Ice The alternate freezing and thawing of
  soil and rock, called frost action or ice
  wedging, is a form of mechanical weathering.

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• 2. Abrasion Abrasion is the grinding and wearing
  away of rock surfaces through the mechanical
  action of other rock or sand particles.
• 3. Wind, Water Gravity Wind, water, and
  gravity carry rocks, causing them to grind
  against one another.

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Three Types of Abrasion (pg. 279)
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Section 1 Weathering
Chapter 10
4. Plants As a plant grows, the force of the
expanding root becomes so strong that it can
break a rock apart. 5. Animals Almost any
animal that burrows causes mechanical weathering
by mixing and digging through soil and rock
particles.
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Section 1 Weathering
Chapter 10
Animals and Mechanical Weathering

• Animals that burrow in the ground break up soil
  and loosen rocks to be exposed to further
  weathering.

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Chapter 10
Section 1 Weathering
Chemical Weathering

• Chemical Weathering is the process by which rocks
  break down as a result of chemical reactions.
• 1. Water Even hard rock, such as granite, can be
  broken down by water.

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• 2. Acid Precipitation The high level of acidity
  in acid precipitation can cause very rapid
  weathering of rock.
• 3. Acids in Groundwater When acidic groundwater
  comes into contact with limestone, the limestone
  is dissolved and forms karst features. Karst is a
  type of topography that is characterized by
  closed depressions or sinkholes, caves, and
  underground drainage

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Acid in groundwater has weathered limestone to
form Rustys Cave in Dade County, Georgia
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Section 1 Weathering
Chapter 10

• 4. Acids in Living Things Some living things,
  such as lichens (which consist of fungi algae
  living together), produce acids that can slowly
  break down rocks.

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• 5. Air Oxygen in the air causes oxidation.
  Oxidation is the chemical reaction in which an
  element, such as iron, combines with oxygen to
  form an oxide. This common form of chemical
  weathering is what causes rust.

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• Show WEATHERING Brain Pop Video