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42 Cards in this Set
- Front
- Back
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What is convection?
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heat transfer within a fluid by current
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What does convection cause?
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differences in temperature and density
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What is density?
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How much mass there is in the volume of a substance?
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What is a convection current?
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the flow that transfers heat within a current
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How does temperature affect density?
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density decreases as heat increases (wax melts)
density increases as heat decreases (ice turns to water) |
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What causes a convection current?
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1. heating and cooling of a fluid
2. changes in fluid density 3. force of gravity |
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What causes a convection current in the earth
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heat from the core and the mantle
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What does the convection current in the earth cause?
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a cycle of rising and sinking in the earth -- has gone on for millions of years
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How does the earth's temperature change as you go deeper into the earth?
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1. cool close to the surface
2. gets hotter at 20 meters 3. goes 1 degree higher for every 40 meters 4. slowly increases |
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What causes high temperatures in the earth
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1. heat left over from the planet's formation
2. radioactive substances that release energy? |
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How does pressure change as you go deeperinto the earth?
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it increases
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What is the earth's crust?
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Layer of rock that rock that forms the Earth's outer skin
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what two things are part of the Earth's crust?
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1. solid rock from dry land
2. the ocean's floor |
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Where is the crust thinnest?
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beneath the ocean
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Where is the crust thickest?
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under mountains
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What is the mantle?
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layer of hot rock at 40 km beneath the surface
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What is the mantle made up of?
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very hot, solid rock
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What are the three layers of the mantle?
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1. lithosphere
2. asthnosphere 3. lower mantle |
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What is the lithosphere?
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the uppermost layer and the crust
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What does lithos mean?
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stone
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How is the asthenoshpere different than the lithosphere?
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the asthenoshpere is:
- hotter - under increasing pressure - soft but still solid |
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What does asthnes mean?
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weak
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Is the lower mantle solid or liquid?
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solid all the way to core
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What is core made up of?
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mostly iron and nickel
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What are the 2 parts of the core
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1. the liquid outer part
2. the solid inner part |
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What is the outer core?
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Molten (melted) metal that surrounds the inner core
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What does the movement of liquid in the core create?
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A magnetic field
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What evidence do we have that the core is magnetic?
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The arrows on the compass point N/S/E/W
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What is the inner core?
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dense ball of solid metal
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Why is the inner core solid?
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the pressure is so great in the inner core that the atoms of iron and nickel can's spread and turn liquid despite the heat
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What does the inner core contain?
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iron, nickel, oxygen, sulfer and silicon.
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In what direction does heat move?
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From warm to cool
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what are 3 types of heat transfer?
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radiation
conduction convection |
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What is radiation?
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transfer of energy through space without direct contact between two objects
(example: sunlight/heat from a flame) |
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Wht is conduction?
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heat transfer withiin a material or between two objects that touch
(heat in pan - up spoon- to hand) |
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What 2 types of evidence do scientists use to find out about the Earth's interior?
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direct evidence from rock samples
indirect evidence from seismic |
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Where do rock samples come from?
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deep inside the earth
sometimes drilled. sometimes blasted up |
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What do rock samples help scientists do?
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make inferences about what it's like inside the earth
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What are seismic waves?
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patterns of energy that are caused by earthquakes
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How do seismic waves help scientists?
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the speed and paths of seismic waves show the structure of the earth
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What are the 3 layers of earth?
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1.crust
2. mantle 3. core |
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How do the 3 layers of earth differ.
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The layers of the earth differ in:
1. size 2. composition 3. temperature 4. pressure |
