How water's properties shape Earth's surface

Water's unusual properties make it the most important agent changing Earth's surface. Its molecules are polar, so water dissolves more substances than almost any other liquid: slightly acidic rain and groundwater, carrying dissolved carbon dioxide, slowly dissolve limestone to form caves, sinkholes, and karst landscapes, and water drives chemical weathering such as the breakdown of feldspar into clay. Water expands by about 9 percent when it freezes, so water that seeps into cracks and freezes can pry rock apart, a process called frost wedging or ice wedging. Water has a very high heat capacity, so oceans and lakes absorb and release large amounts of heat with small temperature changes, moderating climate, and evaporation and condensation move huge amounts of energy through the atmosphere. Cohesion and adhesion let water creep through soil and narrow spaces by capillary action. Flowing water carries sediment and cuts valleys, and the faster it flows, the larger the particles it can move, while glaciers of moving ice carve U-shaped valleys. Water matters deep underground too: water carried down at subduction zones lowers the melting point of mantle rock, producing the magma that feeds explosive volcanoes, and water in soil and rock makes slopes weaker, which is why landslides often follow heavy rain.

This explanation is AI-generated and can occasionally be wrong. 🚩 Report