Which process breaks rocks by physical forces such as freezing and cracking without changing their chemical composition?

Which process breaks rocks by physical forces such as freezing and cracking without changing their chemical composition?

• A. Chemical weathering
• B. Physical weathering
• C. Biological weathering
• D. Erosion

Answer: (B)

Physical weathering is the breakdown of rocks by mechanical forces that do not alter the minerals themselves. For example, when water enters cracks and freezes, it expands and pries the rock apart; repeated freeze-thaw cycles gradually widen those cracks and split pieces off. Other forms include frost wedging, pressure release causing layers to peel, abrasion by wind or water, and roots expanding cracks. The key point is that the mineral composition remains unchanged, just the rock is broken into smaller pieces. This contrasts with chemical weathering, where minerals react with water, acids, or gases and new substances are formed. Erosion is the transport of those weathered pieces away, not the act of breaking them. So the process described is physical weathering.

Physical weathering is the breakdown of rocks by mechanical forces that do not alter the minerals themselves. For example, when water enters cracks and freezes, it expands and pries the rock apart; repeated freeze-thaw cycles gradually widen those cracks and split pieces off. Other forms include frost wedging, pressure release causing layers to peel, abrasion by wind or water, and roots expanding cracks. The key point is that the mineral composition remains unchanged, just the rock is broken into smaller pieces.

This contrasts with chemical weathering, where minerals react with water, acids, or gases and new substances are formed. Erosion is the transport of those weathered pieces away, not the act of breaking them. So the process described is physical weathering.