How Solid Forms

How Solid FormsChapter 2Section 36th Grade Team

StandardsS.6.6.b Students know different natural energy and material resources, including air, soil, rocks, minerals, petroleum, fresh water, wildlife, and forests and know how to classify them as renewable or nonrenewable. Anticipatory Set

What is Soil? (Input)Soil- the loose, weathered material on Earths surface in which plants grow. Bedrock- the solid layer of rock beneath the soil Once bedrock has been exposed to the surface, it gradually weathers into smaller and smaller particles- soilSoil CompositionSoil is a mixture of rock particles, minerals, decayed organic material, water and air. Humus- the decayed organic material that is soilIt is dark colored substance that forms as plants and animal remains decay. It contents nutrients and plants get their nutrients from this. As plants grow they absorb humus. Fertility- of soil is a measure of how well the soil supports plant growth. If it is rich is humus, it has high fertility. Soil Texture Sand feels course, and clay feels smooth and silkySoil texture will depend on the size of individual soil particles. The texture or particle size of soil determines how much air and water the soil can hold. Clay- has a dense, heavy texture and they hold a lot of water so pants grown in them can drown for lack of air Sandy- has a coarse texture and water quickly drains through it killing the plant from lack of water. Loam- soil that is made up of about equal parts of clay, sand, and silt.

Process of Soil FormationSoil forms as rock is broken down by weathering and mixes with other materials on the surface. Soil is constantly being formed wherever bedrock is exposed. Soil horizon- a layer of soil that differs in color, and texture from the layers above it and below it. Horizon A- topsoil= a crumbly, dark brown soil that is a mixture of humus, clay and other minerals. Horizon B-Subsoil=consists of clay and other particles washed down from Horizon A but little humus. Horizon C-contains partly weathered rock

Soil Types Scientists classify the different types of soil into major groups based on climate, plants, soil composition, and whether the soil is acidic or basic. Hot, Wet climates- fertile soil but rain washes way humus and minerals. Soil formation would take more rapidly with this type of weathering. Cold, Dry climates- the soil is often very thinModerate Temps and Rainfall- thickest, most fertile soil forms Soil Types The common plants found in a region are used to classify soil Grassland soil is different from forest soilScientists classify soil by its compositionAcidic- if a substance reacts strongly with some metals and changes blue litmus paper red Basic- if a substance feels SLIPPERY and changes red litmus paper blue. Scientists use the pH scale to measure acidic and basic substances. pHpH of 0= strongly acidic pH of 7= neutralpH of 14 = strongly basic

For plants to grow they need a pH of 6 or 7.5. Living Organisms in SoilSome soil organisms make humus, the material that makes soil fertile. Other soil organisms mix the soil and make spaces in it for air and water. Forming HumusPlants form humus. As plants shed leaves, they form a loose layer of humus When plants die, they become part of litterHumus forms in a process called decomposition. Organisms that live in soil turn deal organic material into humusLiving Organisms in SoilDecomposers are the organisms that break down the remains of dead organisms into smaller pieces and digest them with chemicals. Soil decomposers- fungi, bacteria, worms, other organisms, mites and worms.Fungi- mold and mushrooms. They digest and grow on plant remains. Bacteria causes decay and attack dead organism and their waste in soil Mixing the SoilEarthworms do most of the work of mixing humus with other materials in soil. As Earthworms eat their way through the soil, they carry humus down to the subsoil and subsoil to the surface. Earthworms also pass out the soil they eat as wasteBurrowing animals- mice, moles, prairie dogs, and gophers break up hard, compacted soil and mix humus with it. Earthworms and burrowing animals also mix air into the soil Checking for UnderstandingWhat is humus?What happens to a plant grown in clay?What is the pH of a acid?What is the pH of a basicWhat is the pH of a neutral?What is a decomposer?Bill NyeVarious ArtistsTV Theme SongsiTunes 10.6.3