Water freeze in the crack in this boulder and expands over time piece of the boulder break off what type of weathering effect is this an example of
The described process is an example of frost wedging, which is a type of mechanical weathering.
The type of weathering effect described is known as "frost wedging" or "freeze-thaw weathering."
The type of weathering effect you are describing is called freeze-thaw weathering. This occurs when water seeps into cracks, joints, or pores in a rock or boulder. When the temperature drops below freezing, the water freezes and expands. This expansion puts pressure on the surrounding rock, causing stress. Over time, this repeated freezing and thawing can lead to the weakening or fracturing of the rock, causing pieces to break off.
Freeze-thaw weathering is most common in areas with significant temperature fluctuations, especially in regions with cold winters. It is a form of mechanical or physical weathering because it does not involve any chemical changes to the rock composition, but rather breaks down the rock through physical forces.