Frost Wedging
What happens to water when it gets very cold?
It freezes and it expands
Physical
Salt Wedging
Death Valley, CA
Various salt crystals
Physical
Exfoliation
Physical
Yosemite, CA
Abrasion
Caused by friction from small particles in wind and water hitting rock surfaces
Jebel Kharaz, Jordan
Physical
Thermal Expansion
Most materials expand (get bigger) when they are heated and contract
(get smaller) when they are cooled.
Hot ball
Cold ball
h"p://www.youtube.com/watch?v=hX2Y2IDjuGI Physical
Chemical Reaction
What are some chemical reactions we have talked about this year?
Rust on a car
Rocks with iron can also rust
Chemical
Dissolution
Rocks can dissolve (very slowly!) in water.
Mammoth Cave, KY
Chemical
Biological
Living things can cause rocks to break down.
Tree roots can wedge in the cracks in rocks.
Lichens and moss can also
cause biological weathering.
Biological
h"p://clasfaculty.ucdenver.edu/callen/1202/Ba"le/Destroy/Wx/Wx.html