Earth Science

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WEATHERING Weathering is the process of breakdown of rocks at the Earth’s surface, by the action of water, ice, acids, salts, plants, animals, gravity and changing temperatures. There are three types of weathering: physical weathering, chemical weathering, and biological weathering. Agents of Weathering 1. Water Either in liquid or solid form is one of the agents of mechanical weathering. In liquid form, it seeped into cracks and crevices of rocks and when the temperature dropped, it freezes and definitely will expand in the form of ice. The ice then works as a wedge which slowly widens the cracks and splits the rock. When the ice melts, the liquid water performs the act of erosion by carrying away the tiny rock fragments lost in the split. 2. Salt In the process of haloclasty, salts served as an agent of weathering. Saltwater sometimes gets into the cracks and pores of rock. When it evaporates, salt crystals are left behind and grow in the cracks and pores which caused pressure on the rock and slowly break it apart. 3. Temperature Temperature changes can also contribute to weathering through the process called thermal stress. During thermal stress, rock tend to expand with heat and contract with low temperature. As this happens repeatedly, the structure of the rock weakens and over time crumbles. 4. Plants Plants also served as agents of weathering. Its contribution take place when the seed of a tree being spread in the environment sprout in soil that has collected in a cracked rock. As the roots grow, they widen the cracks, eventually breaking the rock into pieces. Over time, trees can break apart even large rocks. Even small plants, such as mosses, can enlarge tiny cracks as they grow. 5. Animals Animals that tunnel underground, such as moles and prairie dogs, also work to break apart rock and soil. Other animals dig and trample rock aboveground, causing rock to slowly crumble.