SCIENCE CHAPTER 2 REVIEW
THE MAIN IDEAS BY: TREVOR KRAFT AND HANA KEIL
The Rock Cycle
The Rock Cycle is a group of changes. Igneous rock can change into sedimentary rock or into metamorphic rock. Sedimentary rock can change into metamorphic rock or into igneous rock. Metamorphic rock can change into igneous or sedimentary rock.
3 Different Types Of Rock
Sedimentary Rock
Sedimentary rocks are formed by sediment that is deposited over time, usually as layers at the bottom of lakes and oceans. This sediment can include minerals, small pieces of plants and other organic matter
Igneous Rock
Igneous rock forms when magma cools and makes crystals. Magma is a hot liquid made of melted minerals. The minerals can form crystals when they cool. Igneous rock can form underground, where the magma cools slowly. Igneous rock can also form above ground, where the magma cools quickly.
Metamorphic Rock
Metamorphic rocks have been modified by heat, pressure and chemical processes, usually while buried deep below Earth's surface. Exposure to these extreme conditions has changed the mineralogy, texture and chemical composition of the rocks.
Mechanical And Chemical Weathering
Mechanical Weathering
Mechanical Weathering is the process of breaking large rocks into little rocks. Mechanical Weathering has five causes including freezing and thawing, release of pressure, plant growth, actions of animals, and abrasion. The way that the rocks break down is by weathering. Weathering is the breaking down of rock, soil, and minerals.
Chemical Weathering
Chemical weathering also known as decomposition or decay is the breakdown of rock weathering by chemical mechanisms, the most important ones being carbonation, hydration, hydrolysis, oxidation, and ion exchange in solution.
SOIL
Soil Composition
Soil is a mixture of rock particles, minerals, decayed, organic material, water, and air. Humus helps create spaces in soil for the air and water that plants must have.
Conserve Soil
To improve water quality. All forms of life need clean water to survive. Agricultural and urban soil erosion are major sources of sedimentation and contamination of water supplies. To improve wildlife habitat.
Humus
Humus usually refers to the natural decay of material such as leaves in the soil's top layer. Humus is dark, organic material that forms in soil when plant and animal matter decays. When plants drop leaves, twigs, and other material to the ground, it piles up.
Subsoil (B Horizon)
Subsoil is the layer of soil under the topsoil on the surface of the ground. Like topsoil it is composed of a variable mixture of small particles such as sand, silt and/or clay, but it lacks the organic matter and humus content of topsoil.