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Rocks Minerals Soils
SRA Real Science Chapter B4 Rocks, Minerals, and Soils
Question | Answer |
---|---|
traces or remains of plants or animals; formed when parts of plants or animals are preserved in mud; the mud eventually turns to rock | Fossils |
fossils that can be used to help scientists determine the age of rock layers; the remains of animals that lived only during a short time period | index fossils |
This identifies four different times in Earth's history; index fossils have helped scientists develop this | geologic timetable |
solids that form naturally and have a specific chemical makeup and physical form | minerals |
how many minerals are common | about 100 |
elements combine to form this many different minerals | about 500 |
what are some common minerals | quartz, talc, salt, and graphite |
atoms that are arranged in repeating patterns are called this | crystals |
what are four ways that minerals are identified | hardness, luster, color, and the way they break |
the "true" color of a mineral; when you rub a mineral across a white unglazed ceramic tile; the ___ of the mineral always stays the same | streak |
a mixture of rock, plant material, animal material, water and air | soil |
decomposed plant and animal matter | humus |
three examples of different kinds of soil | sand, silt, and clay |
a type of soil that has large grains of rock big enough for you to see | sand |
a type of soil that can only be seen through a magnifying glass; a powdery mixture | silt |
a soil with the smallest grains; can be molded with your hands, forms a hard brick when it dries | clay |
best soil for growing things | a mixture of sand, silt, and clay |
how well a soil holds water | water retention |
if you cut into the earth a remove a slice of several meters deep to see several layers of soil; scientists call these layers this | soil horizons |
things we can use that never run out | inexhaustible resources |
preserving and protecting the soil and to use it wisely | soil conversation |
a process for making the decomposing plant matter necessary for soil | composting |
five factors that influence soil formation | 1. time; 2. type of rock in an area; 3. climate of an area; 4. slope of the land; 5. plants and animals |
five characteristics required to be considered a mineral | 1. must be solid, not a liquid/gas; 2. must be made from nonliving things; 3. must occur naturally on Earth; 4. must be a single substance, always made from exact same elements in exact same proportions; 5. atoms must be arranged in crystals |
rocks can be grouped into these three types | 1. igneous 2. sedimentary 3. metamorphic |
rocks formed when igneous or sedimentary rocks are changed by great heat or pressure | metamorphic |
rocks formed when loose materials, such as small rocks or pieces of dead plants and animals are pressed together | sedimentary |
rocks formed by cooling liquid rock called magma | igneous |
the name of the process by which rocks are always changing, wearing down and then forming again | the rock cycle |
volcanoes make igneous - broken into pieces - eroded/deposited to become sedimentary -- buried deeply/undergo heat & pressure - become metamorphic -- then melt as pushed further into earth -- become igneous again | the steps in the rock cycle |
layers in the soil | top layer is topsoil (A horizon) up to 5 meters deep; subsoil (B horizon) about 1 m deep; C horizon - made of weathered rock; and deeper, solid bedrock |
much topsoil is lost to forces such as wind, rain, and ice; this process is called ___ | erosion |
New soil is being made but it can take this long to make 1 cm of soil | a thousand years |
erosion can destroy 1 cm of soil in less than this amount of time | 5 years |
soil can be lost because of these actions of people | overfarming; raising livestock; logging and mining; strip mining; roads and parking lots bury topsoil |
ways that people can practice soil conversation | farmers can rotate crops; adding nutrients and minerals to farm fields; planting trees; composting |
why is soil so important to people and to animals | many things we need in life we get from the soil; food; plants that make clothes; trees for paper and wood; medicines from plant - people and animals couldn't live without materials from plants grown in soil |