1. Mechanical weathering: the effects of frost
Chapter 4

3. What is freeze-thaw action?
Terms:
Expand
Contract
Freeze
Thaw
Strain/pressure
Scree
Rocks with cracks +
Moisture (rain, dew, fog etc…PRECIPITATION)
Temperature drop below 0°C (Freezing Point)
Freeze thaw action is a type of mechanical weathering where water gathers in the cracks of the rocks. When the temperature drops below freezing point the water freezes and turns into ice. The volume of ice expands the crack of the rock. This puts a great strain on the rock. As the temperatures rise the ice thaws and the rock contracts. Over time this repeated action causes the rock to shatter into scree.