Are cracks that form in a sidewalk during winter are the result of a physical change.?

Yes, cracks that form in a sidewalk during winter can be considered a result of a physical change. This occurs primarily due to the freeze-thaw cycle, where water seeps into existing cracks, freezes, and expands, causing further cracking. The process does not alter the chemical composition of the concrete; instead, it changes its physical structure. Consequently, these cracks are indicative of physical stress and environmental factors rather than a chemical change.