1. 5.1 Weathering

2. Mechanical Weathering
• The physical disintegration of rock, resulting in
smaller fragments

3. Frost wedging
• The mechanical breakup of rock caused by the
expansion of freezing water in cracks and
crevices

4. Talus
• An accumulation of rock debris at the base of
a cliff

5. Exfoliation
• Type of weathering caused by reducing
pressure on a rock surface, allowing slabs of
outer rock to break off in layers

6. Chemical weathering
• The process by which the internal structure of
a mineral is altered by the removal and/or
addition of elements

7. Key Concept
• Mechanical weathering occurs when physical
forces break rock into smaller and smaller
pieces without changing the rock’s mineral
composition.

8. Key Concept
• In nature, three physical processes are
especially important causes of mechanical
weathering: frost wedging, unloading, and
biological activity.

9. Key Concept
• Chemical weathering is the transformation of
rock into one or more new compounds

10. Key Concept
• Two others factors that affect the rate of
weathering are rock characteristics and
climate