Transcript Chemical Weathering - Middletown Public Schools

Chemical Weathering
Weathering
• What is weathering?
– Weathering is the disintegration and
decomposition of rock at or near the surface
of the earth.
Weathering
• Types of Weathering
– Mechanical
• Physical disintegration of rock into smaller
fragments, each with the same properties as the
original.
– Chemical
• Process by which the internal structure of a
mineral is altered by the addition or removal of
elements.
• A chemical process CHANGES or ALTERS the
composition of the rock during disintegration
Chemical Reactions
Characteristics of Chemical Reactions:
Bubbling
Foaming
Change in Temperature
Color Change
Factors that Effect Chemical
Weathering
– Temperature
• Chemical decomposition of rock will be faster in warmer
climates.
– Hardness
• Rocks and minerals that are “soft” will weather faster than
those that are hard. Limestone is not as hard as granite.
– Time
• Natural chemical weathering is a slow process. The longer a
rock has been exposed to chemical decomposition, the more
likely it is to be weathered
Weathering and Soil Formation
• Mechanical and Chemical Weathering
Promote Soil Formation
• Soils contain small pieces of rocks and
minerals as well as organic material.
Soil Formation
Chemical Weathering by Acids
• Acids dissolve some of the minerals in
rocks which promotes disintegration and
weathering
• In our environment, chemical weathering
can occur as a result from acid rain and
acids produced by plant roots and plant
decomposition.
Effects of Acid Rain