Question

where on earth would physical weathering from tempure changes be most common least common explain

Answer 1

Short answer: Physical weathering from temperature changes is most common where rocks experience large temperature swings and/or frequent freeze–thaw cycles — especially hot deserts (large daily ranges → thermal stress) and temperate-to-alpine regions that regularly cross the freezing point (freeze–thaw or frost shattering). It is least common where temperature is stable (little daily or seasonal change) or where liquid water and freezing cycles are absent — e.g., humid tropical rainforests and the cold, dry interiors of polar ice sheets.

Details and why:

- Two main temperature-driven physical processes
- Thermal expansion/contraction (thermal stress, exfoliation): repeated heating and cooling of rock causes outer layers to expand and contract and eventually crack.
- Frost wedging/frost shattering: water enters cracks, freezes, expands by ~9% and forces cracks wider when temperatures repeatedly cross 0 °C.

- Most common places
- Hot deserts (e.g., Sahara, Mojave): very large diurnal temperature ranges (hot days, cool nights) cause strong thermal stresses and exfoliation. Little vegetation means rock surfaces are exposed. Rocks that absorb heat (dark rocks) are especially affected.
- Temperate and alpine mountain regions (e.g., the Alps, Rockies, Himalaya): frequent cycles of thaw and freeze in the active season make frost wedging very effective, especially where water is available and rocks are jointed or fractured.
- Areas with strong seasonal swings across 0 °C (continental interiors, high plateaus): repeated freeze–thaw across seasons accelerates mechanical breakdown.

- Least common places
- Humid tropical rainforests (e.g., Amazon, Congo, Borneo): temperatures are fairly constant year‑round and diurnal ranges are small; chemical weathering dominates. Also dense vegetation and soil cover protect bedrock from direct thermal stress.
- Cold, dry polar interiors (e.g., central Antarctica, central Greenland): temperatures remain well below freezing most of the time so there is little liquid water to freeze and thaw; mechanical weathering from temperature cycling is therefore limited.
- Deep subsurface or ocean-floor environments: stable temperatures and lack of air/water cycles mean little thermal-weathering at the surface level.

Other important controls: rock type (brittle, highly jointed or layered rocks weather faster), presence of water (needed for frost wedging), slope/exposure, and vegetation or soil cover (which buffers temperature swings).