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earth science unit 1
rocks and other stuff
Term | Definition |
---|---|
earth | 4.6 billion years old |
hydrosphere | ocean sphere. most prominent feature on earth. nearly 71% of earth's surface |
atmosphere | thin, tenuous blanket of air |
biosphere | includes all life |
geosphere | made of crust, mantle, and core. |
crust | thin, rocky outer layer |
mantle | the 2980 km thick layer of earth below crust |
core | innermost layer, beneath mantle (outer and inner) |
plate tectonics | theory that proposes that earth's outer shell consists of individual plates |
latitude | north or south of equator. |
longitude | east or west of prime meridian. each line is 15 degrees which equals one hour. |
zenith | point directly overhead |
polaris | north star, can only be seen in northern hemisphere. use latitude to determine altitude |
system | any size group of interacting parts that form a complex whole. |
sun | drives external processes like weather, ocean circulation, erosional processes |
earth's interior | drives internal processes like volcanoes, earthquakes, mountain building. |
environment | surrounds and influences organisms |
renewable resource | can be replenished (ex: plants, energy from water and wind) |
nonrenewable resource | cannot be replenished in near future. (ex. fossil fuels: metals, fuels) |
elements | basic building blocks of minerals |
atoms | smallest particles of matter |
protons | positive electrical charges |
neutrons | neutral electrical charges |
electrons | negative electrical charges |
energy levels/shells | surround the nucleus, contains electrons |
isotopes | have the same number of protons but varying numbers of neutrons |
compound | consists of two or more elements that are chemically combined in specific proportions |
ion | an atom that gains or loses electrons |
ionic bonds | form between positive and negative ions |
covalent bonds | form when atoms share electrons |
metallic bonds | form when metal ions share electrons |
mineral | naturally occurring, solid substance that has an orderly crystalline structure. definite chemical composition and generally considered inorganic |
mineral formation | crystallization from magma, precipitation, pressure + temperature, hydrothermal solutions |
silicates | silicon and oxygen combine to form a structure called the silicon-oxygen tetrahedron |
carbonates | minerals that contain the elements carbon and one or more other metallic elements |
oxides | minerals that contain oxygen and one or more other elements, which are usually metals |
sulfates and sulfides | minerals that contain the element sulfur |
halides | minerals that contain a halogen ion plus one or more other elements |
native elements | minerals that exist in relatively pure form |
streak | color of a mineral in its powdered form |
luster | used to describe how light is reflected from the surface of a mineral |
hardness | measure of the resistance of a mineral to being scratched |
mohs scale | consists of 10 minerals arranged from 10 (hardest) to 1( softest) |
cleavage | tendency of a mineral to cleave, or break, along flat, even surfaces |
fracture | uneven breakage of a mineral |
porphyritic texture | occurs in rocks with different-size minerals that cool at different rates |
granitic composition | occurs when igneous rocks contain mostly quartz and feldspar |
basaltic composition | occurs when rocks contain many dark silicate MATERIALS |
andesitic composition | occurs in rocks with a combination of granitic and basaltic rocks |
ultramafic | rocks are composed almost entirely of dark silicate minerals |
contact metamorphism | magma moves into rock, minor changes |
regional metamorphism | large scale deformation and high grade metamorphism, intense changes like mountain building |
agents of metamorphism | heat, pressure, hydrothermal solutions |