Resumen Science

Science
Chapter 1
 Weathering: process that break down rock at earth’s surface.
 Erosion: the removal of rock particles by wind, ice, water, or gravity.
 Uniformitarianism: process that happen in the past are occurring today.
 Mechanical weathering: process that breaks down rock physically.
 Abrasion: grinding away of rock by particles carried by wind, water, ice, or gravity.
 Icewedging: process that splits rock when water seeps into cracks, then freezes and expands.
 Chemical weathering: process that break down rock by chemical changes.
- acid rain, oxygen, carbon dioxide…
 Water: most important cause of chemical weathering. It weathers the rock by dissolving it.
 Oxygen: oxidation is when iron combines with oxygen in the presence of water.
 Carbondioxide: Dissolves in rainwater and in water that sinks through air pockets in the soil.
 Living organism: a seed as it grows, its roots push in cracks in it. As the roots grow it produce wet acids that dissolve rock around the roots.
 Acid Rain: it’s created when people burn oil , coal, gas for energy. As it is burned, it’s polluted the air with sulfur, carbon, and nitrogen compounds.
Factors that determine the rate at which weathering occurs:
 a- Type of rock: Rock made of minerals don’t dissolve easily in water weathers faster. Permeable: means that a material is full of tiny, connected air spaces that allow water to seep thought it.
 b- Climate: average of weather conditions in an area for a long time.
 Human activities: Actions of humans, that polluted the air, canincrease the rate of weathering.


 Define weathering and erosion.

 What are the 2 types of weathering? Explain them.
 What are 2 factors that affect the rate of weathering?
 Write the 5 causes of chemical weathering.

 Soil: loose, weathered material on Earth’s surface.
 Bedrock: solid layer beneath the soil.
 Soil Composition:
- -Humus: dark- colored substance that formsas plant and animas remains decay
- -fertility: how well the soil supports plant growth.
 Soil Texture: Ex: sand feels coarse and grainy, but clay feels smoothly and silky.
- loam: soil that is made of clay, sand, and silt.

 Soil forms as rock is broken down by weathering and mixes with other materials on the surface. Also it’s formed when bedrock is exposed. The rate at whichsoil forms depends on climate and type of rock.
 Soil horizon: a layer that is different in color and texture from others.
 Topsoil: a mixture of humus, clay and other materials.
 Subsoil: consists of clay and other particles washed down from the A horizon.
 Scientists classify the different types of soil into mayor groups based on climate, plants, and soil composition.
 FormingHumus:
 - Litter: As plant shed their leaves, they form a loose layer .
 Decomposers: are smaller organisms that break the remain of dead organisms into smaller pieces and digest them with chemicals.
 Examples: Worms, mite, bacteria, fungi (mushrooms).
 Thee main factors to classify soil are…
 Give tree examples of decomposers.
 What’s fertility?
Define soil.
 Sod: thick mass oftough roots at the surface of Earth.
 Natural resource: anything in the environment that human use. (Ex. Soil)
 Loss of fertility: soil can be damaged when it loose it’s fertility. If it loss it, farmers can grow their crops so they go to another place.
 Loss of topsoil: Whenever soil is exposed, water and wind can quickly erode it. Plant cover can protect soil from erosion.
 Dust bowl:area of Great Plains where wind erosion caused soil loss during the 1930s.

 Soil conservation: management of soil to prevent its destruction.
 Contour plowing :farmers plow their fields along the curves of a slope. This helps the runoff excess rainfall and prevents it form washing soil away.
 Conservation plowing: farmers disturb the soil and its plant cover as little as possible.
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