Which pair lists two examples of physical (mechanical) weathering?

Which pair lists two examples of physical (mechanical) weathering?

• A. Biological weathering from root growth.
• B. Oxidation and acid dissolution.
• C. Freeze-thaw cracking and abrasion.
• D. Erosion and deposition.

Answer: (C)

Physical weathering is the mechanical breaking apart of rocks without changing their chemical makeup. It happens when forces physically crack or wear down rock. Freeze-thaw cracking is a classic example: water seeps into cracks, freezes, expands, and pries the rock apart. Abrasion is another: bits of rock and sediment grind the surface as they rub against each other or against flowing water or wind, wearing the rock down without chemical changes. Other options involve chemical changes, like oxidation or acid dissolution, which chemically alter minerals, or involve moving weathered material (erosion and deposition) rather than breaking the rocks themselves.

Physical weathering is the mechanical breaking apart of rocks without changing their chemical makeup. It happens when forces physically crack or wear down rock. Freeze-thaw cracking is a classic example: water seeps into cracks, freezes, expands, and pries the rock apart. Abrasion is another: bits of rock and sediment grind the surface as they rub against each other or against flowing water or wind, wearing the rock down without chemical changes.

Other options involve chemical changes, like oxidation or acid dissolution, which chemically alter minerals, or involve moving weathered material (erosion and deposition) rather than breaking the rocks themselves.