7 weathering and erosion Weathering – the process that breaks down rock and other substances at the Earth’s surface.Erosion – forces of erosion carry the pieces away…..weathering and erosion work together to break down and carry away rocks on Earth’s surface.
8 Uniformitarianism – principles that operate today operated in the past vocabularyUniformitarianism – principles that operate today operated in the past
9 Which is a cause of chemical weathering? WARM-UP #3Which is a cause of chemical weathering?
14 MECHANICAL WEATHERING Mechanical weathering – weathering where the rock is broken into smaller pieces….each piece is still the same composition….mechanical weathering is a slow process
15 EXAMPLESFreezing and thawing, release of pressure, plant growth, actions of animals, abrasionAbrasion – grinding away of rocks by rock particles carried away by wind, water, ice, or gravityIce wedging – water seeps into cracks – expands when it freezes – ice is like a wedge that breaks the rock apart
16 When dead plants and animals decay, they form WARM-UP #5When dead plants and animals decay, they form
21 Chemical weatheringProcess that breaks down rock through chemical changes………..causes are the action of water, oxygen, carbon dioxide, living organisms, and acid rain.
22 VOCABULARYOxidation – when iron combines with oxygen in the presence of water………….rustPermeable – rock that is full of tiny holes…allows water to seep through easily….permeable rocks will weather quickly when exposed to chemical weathering.
23 In the United States, most of the eastern states are covered with WARM-UP #7In the United States, most of the eastern states are covered with
34 VOCABULARYFertility – measure of how well the soil supports plant growthLoam – soil made up of equal parts of sand, clay and siltSoil horizon – is how the soil develops into layers ………the layers differ in color and texture
35 WARM-UP #11The movement of rock pieces and other materials on Earth’s surface is called ____________________________.
40 TOPSOIL AND SUBSOILTopsoil – is horizon A ….crumbly, dark brown soil that is a mixture of humus, clay and other mixturesSubsoil – is horizon B….clay and other particles washed down from horizon A…little humus
41 LITTER AND DECOMPOSERS Litter – is what is left of the plant before it adds to humus…..leaves, roots, and the plant itself when it dies.Decomposers – organisms that break down the remains of dead organisms into smaller pieces and digest them with chemicals.
42 WARM-UP#13The scraping of rock by wind-blown pieces of rock is called __________________________.
51 VOCABULARYDust Bowl – ruined farmland on Oklahoma and parts of the surrounding states…..caused by years of droughts and lots of plowing tuned the top soil to dust and it blew away.Soil Conservation – management of the soil to prevent it’s destruction.
52 Different kinds of rock weather at different ___________. WARM-UP #17Different kinds of rock weather at different ___________.
56 PLOWINGContour Plowing – plow the fields along the curve of the slope….slows runoff and preserves the soil from erosion.Conservation Plowing – disturb the plant cover and soil as little as possible…dead weeds and stalks are left in the ground to help return soil nutrients.
57 CROP ROTATIONFarmers plant different crops in the field each year………helps maintain the nutrients in the soil
58 Loss of _____________ causes soil to lose its fertility. WARM-UP #19Loss of _____________ causes soil to lose its fertility.