Ch 2 - Modern Earth Science - Vocabulary
Terms
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- true shape of earth; slightly flattened sphere, due to earth's rotation
- oblate spheroid
- imaginary striaght line which runs through the earth from the North Pole to the South Pole
- Axis
- all the earths water
- hydrosphere
- percentage of earth's water which is salty
- 97%
- layer of gases surrounding the earth
- atmosphere
- what are the two most abundant gases in atmosphere and their percentages?
- 78% nitrogen and 21% oxygen
- thin, sold outermost zone of the earth; makes up 1% of earth's mass
- crust
- crust underlying world's oceans; thin, only 5-10 km thick
- oceanic
- crust underlying earth's continetns. vaires 32 -70 km in thickness-thickest under mountains
- continental
- zone of rock nearly 2870 km thick which lies below the earth's outermost layer; divided into upper and lower regions, this zone makes up 2/3 of the earth's mass
- mantle
- this is the uppermost portion of the mantle, and TOGETHER WITH THE CRUST ON TOP OF IT - forms a rigid layer which is 65 - 100 km thick
- lithosphere
- below core this is about 200 km thick. It is sold rock, but because of enormous heat and prssure, this layer flows like putty
- asthenosphere
- The term which describes the ability of a solid to flow
- plasticity
- Forms the center of the earth, divided into inner and outer sections - made mostly of iron, this layer makes up 1/2 of the earth's mass
- core
- Dense layer of liquid iron about 2,190 km thick
- outer core
- Dense sold about 2,680 km diameter at the very center of the earth - mostly iron
- inner core
- Vibrations which originate at or near earth's surface due to earthquake or explosion and move through the earth
- seismic waves
- faster of two seismic wave types; they can move through solid, liquid or gas
- P waves
- Slower of two seismic waves types; they can only move through solid materials
- S waves
- Seismic waves travel ? through material which is more dense/rigid
- faster
- Short for Mohorovocic Discontinuity, this is the boudary between the crust and the mantle. Discovered because seismic waves speed up as they leave the less dense crust and enter the more dense mantle.
- Moho
- Locations on the earth more than 103 degrees from earthquake/explosion causing seismic waves where no secondary waves are felt, due to the fact that they cannot get through the liquid outer core of the earth.
- S wave shadow zone
- Locations on the earth more than 103 degrees but less than 143 degrees from earthquake/explosion causing seismic waves where no secondary waves are felt, due to the fact that they cannot get through the liquid outer core of the earth.
- P wave shadow zone
- Region of space (shich extends out past the atmosphere) affected by the earth's magnetic field
- magnetosphere
- Motions within this layer of the arth are thougth to be responsible for the creation of earth's magnetic field
- liquid iron outer core
- Force of attraction which exists between all matter in the universe- the most imporant things you will learn about all year. Its the law!
- gravity
- the amount of matter in an object
- mass
- the amount of gravity force exerted on a mass
- weight
- The amount of gravitiational attraction between two objects depends upon: 1) the MASSES of the two objects and 2) the DISTANCE between the two objects
- Law of Gravitation