Geosci 40 Exam 1 review
Terms in this set (83)
Proposed relationship about the natural world that can be tested and then verified or disproved
Statement that explains observations. Becomes theory when hypothesis is constantly observed
Explains events in nature that were sure of
A controlled test to examine aspects of nature
truth is based on application of a standardized method and repeated test to confirm the result, subject to change as new methods develop
Belief based thinking
truth is based on authority, can't be disproven. Ex.) God and heaven
data and observation
How long ago did big bang occur?
13.7 billion years ago
How long did it take for Universe to cool? What formed after?
1 million years, atoms formed
What is the most abundant element? Why?
Hydrogen because it has 1 proton and 1 neutron... first element
What comes 1 billion years after Big Bang?
Stars and galaxies form
rotating agglomeration of stars, dust, gas, debris
massive spheres of gas, are like pressure cookers for making heavy elements
What do starts start out as?
How are heavier elements made?
When stars collapse due to GRAVITY, temperature rises and nuclear fusion occurs. Nuclear fusion produces up to Fe. Continued collapse leads to supernova explosion which create elements like Au, Hg, U
When did our solar system form?
5 billion years ago as a porto solar system nebula
porto solar system nebula
rotating disc like mass with lighter compounds to the outside and the heavier rocky material in the middle.
What zone is earth in? Why?
Goldilocks zone, because the position allows it to sustain water and life
Formation of earth:
Earth is segregated by mass with rocky material spinning in orbit with Earth. This lead to collisions= heat. Radioactive decay=heat. This lead to a molten Earth with heavy materials falling to the center and "slush" at the surface.
When did Earth's crust form
4.6 million years ago
How and when did we get our moon?
30 million years after the crust formed, a Mars sized planetoid collided with earth and the chunk that flew off became the moon
What did gravity allow?
Earth's denser items to experience more gravitational attraction
What process would help early matter pull together to form stars and galaxies?
How long did it take for Earth to cool?
500 million years
Where does our water come from?
Water vapor evaporating from volcanos and icy comets crashing into earth
What are Earth's layers?
crust, mantle, outer core, inner core
low density but cold and rigid
higher density and warm (partially melted)... flows slowly
warmer, but higher density still... flows slower than asthenosphere
hot but dense, VERY slow flow
hot and very dense (solid)
What causes plate tectonics?
Heat in Earth's interior causing convection. Asthenosphere and mantle convection drives plate tectonics
What are the main sources of Earth's heat?
radioactive decay of elements in the core and the remaining heat from collisions during beginning of Earth
the deeper into the Earth you go, the hotter it gets
occurs when a fluid is heated, expands and becomes less dense, and rises
the ability of an object to float in a fluid by displacing a volume of fluid equal in weight to the floating objects own weight
Divergent plate boundary
Spreading center, plate material created
Transform plate boundary
plates slide past one another, plate material conserved
Convergent plate boundary
subduction zone, plate material destroyed
plate is dragged along with mantle convection cell
gravitational "push" away from mounded, buoyant mid-ocean ridge (important)
cold, old lithosphere "pulls" as it falls back into the mantle (important)
Why are ocean ridges high spots?
because as the plates spread apart, the magma flows up creating ocean ridgelines.
Where do subduction zones occur at?
Where do ridges form?
Divergent margins new crust (new ocean floor) born
Why are convergent margins low spots?
because when the plates collide into each other, it destroys the material, which then sinks back down into the asthenosphere
Ocean basin are low sports on earth because
Ocean crust is thin and dense relative to continental crust
How much do plates move per year?
1-10 cm... the same rate at which your fingernails grow
Where are trenches formed?
convergent margins (subduction zones)- its old crust recycled back down into the mantle
Lowest spots on Earth are in _________________
deep sea trenches
Big earthquakes and volcanos are associated with what?
subduction zones (convergent margins)
What makes water like tiny magnets?
covalent hydrogen bonds that create polarized particles
a group of atoms held together by chemical bonds
rapid flow to equalize pressure
Heat Energy produced measures what?
measures both how many molecules are vibrating and how fast they are vibrating (measures in calories)
amount of heat required to raise the temperature of 1 gram of water by 1 degrees C
an object's response to the addition or removal of heat (energy)... temperature only records how rapidly molecules are vibrating. Measured in Celsius, Farenheight
heat that is hidden; energy required to change state, but does not change temperature
Heating a material will make its density_____________
What are molecules like in the 3 states?
Solids have molecules that are rigid and not moving very fast. Liquids have more free flowing molecules that allow it to form to the object it's in. Gases having extremely fast moving particles that bounce off one another
Latent heat of fusion (melting)
Latent heat of vaporization (precipitation)
how long it takes for something to change temperature
Water has _________ heat capacity
Negatively charged ion
Positively charged ion
Most abundant elements found in seawater
Na and Cl
water is a ___________ solvent
good; it can dissolve things (the universal solvent)
sources of salt in the ocean
dissolved rocks/minerals from land, oceanic crust, volcanic emissions, and hydrothermal activity
sources of sinks of salts in the ocean
sediment deposits (limestone), Life (organisms eat to make shells), Plate tectonics (subduction returns material to the interior), and Hydrothermal activity
Are sources and sinks equal?
yes, always equal
What is salinity influenced by?
Temperature. (hot temps.= more evaporation), river input (freshwater dilutes the salinity), and ice melting
the average length of time an element spends in the ocean. The most abundant elements in the ocean have long residence times
Equation for residence time
Total amount of seawater (kg)/Input rate (kg/yr)
__________ and ___________ influence water density
Temperature and salinity.
Most dense water and least dense water
cool salt water and warm fresh water
water molecules stick to other molecules
water molecules stick to other stuff
doesn't change temperature easily
Where would be the best place for gases to dissolve?
Cold, fresh water
How does carbon dioxide (CO2) in the atmosphere change ocean chemistry
Atmospheric carbon dioxide (CO2) is absorbed by the ocean, this causes more H ions meaning the water is more acidic (lower pH)