Download Weathering

Weathering
Weathering is the breaking
down of rocks and other
materials on the earth’s
surface
In other words, Weathering is
when rocks are broken into
soil, sand, and sediment (tiny
pieces or particles).
Weathering involves two
processes that often work
together to decompose or
break down rocks.
What are 2 Types of
Weathering?
Chemical
&
Mechanical
Weathering
Chemical weathering, or
decomposition, takes place when
some of the rock’s minerals are
changed into different
substances.
Chemical processes that cause
weathering
•Acid dissolves minerals in rocks (examples: carbonic
acid, acid rain and plant acid)
•Acid rain can weaken rocks, corrode metal and
even kill trees.
•Oxygen combines with iron minerals and sulfur minerals
changing the composition of the rock and forming rust.
This is called oxidation.
•Dissolution- Soluble compounds such as limestone
are dissolved. This often forms caves.
Chemical processes that cause
weathering
•Acid dissolves minerals in rocks (examples: carbonic
acid, acid rain and plant acid)
•Acid rain can weaken rocks, corrode metal and
even kill trees.
•Oxygen combines with iron minerals and sulfur minerals
changing the composition of the rock and forming rust.
This is called oxidation.
•Dissolution- Soluble compounds such as limestone
are dissolved. This often forms caves.
Plant acid?
Lichens such as these growing on the rocks in
the picture can produce weak acids that
react with the rock.
Chemical processes that cause
weathering
•Acid dissolves minerals in rocks (examples: carbonic
acid, acid rain and plant acid)
•Acid rain can weaken rocks, corrode metal and
even kill trees.
•Oxygen combines with iron minerals and sulfur minerals
changing the composition of the rock and forming rust.
This is called oxidation.
•Dissolution- Soluble compounds such as limestone
are dissolved. This often forms caves.
Acid rain…what is the
cause?
How acid rain forms…
What causes it?
What are the effects?
1908
to
1969
Acid rain has eaten away this
limestone statue.
Acid Rain
3000 year old Egyptian Obelisk
3000 year old Egyptian Obelisk
after 100 years in NY
http://www.epa.gov/acidrain/educati
on/site_students/acid_anim.html
Chemical processes that cause
weathering
•Acid dissolves minerals in rocks (examples: carbonic
acid, acid rain and plant acid)
•Acid rain can weaken rocks, corrode metal and
even kill trees.
•Oxygen combines with iron minerals and sulfur minerals
changing the composition of the rock and forming rust.
This is called oxidation.
•Dissolution- Soluble compounds such as limestone
are dissolved. This often forms caves.
Oxidation…what is it?
Oxidation reactions involve a increase in
oxidation state--in other words, the
transfer of electrons from a compound
that is oxidized to the compound that
oxidizes it. Oxygen gas is a major
component of Earth's atmosphere and is
fairly reactive--so much so, in fact, that
it's good at combining with metals and
compounds in minerals, oxidizing or
"rusting" them.
Huh??
the interaction between oxygen
molecules and all the different
substances they may contact
Oxidization
Oxidation turned these
rocks in Nevada's Valley of
Fire red.
Chemical processes that cause
weathering
•Acid dissolves minerals in rocks (examples: carbonic
acid, acid rain and plant acid)
•Acid rain can weaken rocks, corrode metal and
even kill trees.
•Oxygen combines with iron minerals and sulfur minerals
changing the composition of the rock and forming rust.
This is called oxidation.
•Dissolution- Soluble compounds such as limestone
are dissolved. This often forms caves.
Dissolution-forming
caves?
Easy answer…when rain water
seeps into the ground and
dissolves the limestone
underneath.
Linville Caverns,
North Carolina