Transcript Weathering and Erosion - White Plains Public Schools

Aim: Weathering and Erosion
Weathering
• The breakdown of the materials of Earth’s
crust into smaller pieces.
1. Physical Weathering
• Process by which rocks are broken down
into smaller pieces by external conditions.
• Types of Physical weathering
– Frost heaving and Frost wedging
– Plant roots
– Friction and impact
– Burrowing of animals
– Upward Expansion of Rock
– Temperature changes
Frost Wedging
Frost Heaving
Plant Roots
Friction and Repeated Impact
(Stream ABRASION)
Burrowing of Animals
Upward Expansion of Rock due to the
releasing of pressure of overlying rock
unloading off the surface. (notice the
peeling of the rock) Ex. Granite
(Exfoliation…peeling)
Temperature Changes
Part II Chemical Weathering
• The process that breaks down rock
through chemical internal changes.
• The agents of chemical weathering
– Water
– Oxygen
– Carbon dioxide
– Living organisms
– Acid rain
KEY IDEA: Water plus humid
and warm environments
• Water weathers rock by dissolving it
Oxygen
• Iron (Fe) combines
with oxygen (O2) in
the presence of
water in a process
called oxidation
• The product of
oxidation is rust
Carbon Dioxide
• CO2 dissolves in rain water and makes
carbonic acid
• Carbonic acid easily weathers Limestone
and marble …key mineral is CALCITE
Living Organisms
• Lichens that grow on rocks produce weak
acids that chemically weather rock
Acid Rain
• Compounds from burning coal, oil and gas
react chemically with water forming acids.
• Acid rain causes very rapid chemical
weathering
Karst Topography
• A type of landscape in rainy regions where
there is limestone near the surface,
characterized by caves, sinkholes,
and disappearing streams.
• Made by chemical weathering of
limestone
Features of Karst: Sinkholes
Features of Karst: Caves
Features of Karst: Disappearing
Streams
Erosion
• The process by which water, ice, wind or
gravity moves fragments of rock and soil.
A BIG KEY is Water Erosion
• Rivers, streams, and runoff
Ice Erosion
• Glaciers-Ice moves
and picks up rock
Wind Erosion- mostly in dry
climates
Mass Movements
• Landslides, mudslides, slump and creep
landslide clip.mpeg
SOME MOVIES (Brain Pop)
PHOTOS
http://glencoe.mcgrawhill.com/sites/dl/free/0078600499/164213/00
050754.html
http://science.nationalgeographic.com/sc
ience/photos/weathering-erosiongallery.html
ANIMATION:
http://ees.as.uky.edu/sites/default/files/el
earning/module07swf.swf