Weathering

• Water gathers in the cracks in rocks during the day.

  2. At night, if the temperature drops below 0° Celsius, the water freezes

  to become ice. This puts pressure on the rock as the ice expands by

  up to 10%. The next day the water thaws and melts again.

  3. Repeated freezing and thawing results in the rock becoming weak and

  breaking into smaller pieces. These pieces then roll down the slope

  and gather, where they are known as scree.