Download 10.13.16vocab walk-blog

Weathering
•The Physical and chemical processes
that break down rock at Earth’s surface.
•The breakdown of Earth’s crust into
smaller pieces.
Mechanical Weathering
• Mechanical weathering is simply the breakdown
of rock into smaller pieces by physical means.
• Agents or causes of mechanical weathering
include:
• Ice
• Wind
• Water
- gravity
- plants
- animals
Ice (Frost) Wedging
•Mechanical weathering caused by the
freezing and thawing of water that
seeps into cracks in rocks.
Plants (Root Growth)
• As a plant grows, the force of the
expanding root becomes so strong that it
can break a rock apart.
Release of Pressure
• As erosion removes material from the surface
of a mass of rock, pressure on the rock is
reduced.
• This release of pressure causes the outside of
the rock to crack and flack off in layers.
Abrasion
•Abrasion is the grinding and
wearing away of rock surfaces
through the mechanical action
of water, wind, or ice.
ICE
WIND
WATER
Animals
• Animal that burrows causes mechanical
weathering by mixing and digging through
soil and rock particles.
• They cause to the ground break up soil
and loosen rocks to be exposed to further
weathering
Chemical Weathering
• The chemical breakdown of rocks and minerals
into new substances.
• Water
• Acid Precipitation
• Acid in Ground Water
• Acids in Living Things
• Air (Oxidation)
Oxygen
•A chemical change in which a
substance combines with oxygen to
form forms rust.
•Ex: iron, combines oxygen to form an
iron oxide (rust).
Living Organism
•Acids in Living Things Some living
things, such as lichens, produce
acids that can slowly break down
rocks.
Lichens, which consist of fungi and algae living
together, contribute to chemical weathering.
Chemical Weathering by Water
(Acid Rain)
•Compounds from burning coal, oil, and
gas react chemically with water to
form acids.
• Acid Rain
• Acid ground water
CO2 – Carbon Dioxide
• CO2- dissolves in rain water and creates
carbonic acid.
• Carbonic acids easily weathers limestone
and marble.