Physical Weathering

Physical Weathering

1. frost action

   • freezing water in cracks of stone
   • ice has a 9% higher volume than water
   • pressure of frozen water breaks stone into smaller pieces
   • takes place in cold and humid envionments

2. salt crystal growth

   • under hot temperatures water evaporates from the ground
   • salt and other materials remain the ground
   • growing crystals build up pressure and break rock and soil into smaller pieces
   • in some regions salt crust can develop

3. thermic weathering

   • extreme difference in temeperature between day and night
     • in some deserts like Takla Makan the difference can be more than 70%
   • rocks shrink at night and expend during the day
     • rocks are not elastic thus, parts of the stone break away
   • takes also place in more moderate climates

4. root action

   • roots of trees and other plants argue continuity
   • roots can grow in cracks
   • the pressure of grwing roots is strong enough to break rocks
   • root action takes place wherever plants can grow