Physical weathering, also known as mechanical weathering, involves the breakdown of rocks and minerals into smaller pieces without altering their chemical composition. Here are two phenomena that contribute to physical weathering:
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Thermal Expansion and Contraction:
- Temperature fluctuations, especially between day and night, can cause the expansion and contraction of rock material. When rocks heat up during the day, they expand; when they cool down at night, they contract. This repeated cycle can create stress within the rock, leading to the development of cracks and fissures over time. This process is especially pronounced in deserts, where temperature variations are significant between day and night.
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Frost Wedging:
- Frost wedging occurs when water seeps into the cracks and pores of rocks. When temperatures drop, this water freezes and expands, exerting pressure on the surrounding rock. As the cycle repeats—thawing and freezing—the rock fragments become increasingly dislodged and can eventually break apart. This phenomenon is common in climates where temperatures fluctuate around the freezing point, particularly in mountainous and polar regions.
Both of these processes contribute significantly to the breakdown of rocks in natural environments, leading to the gradual erosion and alteration of landscapes.
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