Download Weathering- breaking down of rocks into smaller pieces

Weathering- breaking down of rocks into
smaller pieces
2 Types:
Physical(Mechanical) & Chemical
1. Physical Weathering- rocks are
physically broken down into smaller
pieces
Agents of Physical Weathering
a. Freezing & Thawing – water moves
into cracks, freezes, expands and
thaws(process repeats)
Ex.) Forms pot holes
b. Abrasion – process of wearing away
of rock through collision of
particles
c. Heating and Cooling – rocks crack
through repeated expansion and
contraction due to heating and
cooling
d. Plant Growth – roots can crack open
rocks
e. Animal Action – animals can move
sediment
Physical Weathering is dominant in Wet/Cold
environments.
2. Chemical Weathering – breakdown of rocks
through chemical processes
a. Water – minerals in rocks can get
dissolved in water
b. Oxygen – rocks that contain iron can
rust
c. Carbon Dioxide – dissolved in water
it can form carbonic acid
d. Acid Rain – minerals in rocks will
chemically react with acid
e. Living Organisms – certain plants and
animals release acids
Chemical Weathering is dominant in Hot/Wet
environments.
Water is the most powerful weathering agent.
Factors that Affect the Weathering Rates
1. Type of Rock - the stronger the rock the more
resistant it will be to physical weathering
 Some rocks like limestone are less resistant
to chemical weathering
2. Climate
 High temperatures will increase the rate
of a chemical reaction
 Wet environments will increase the rate of
physical and chemical weathering
3. Surface Area – an increase in surface area
will increase the rate of weathering