Unit 6 · Segment 3: The Distribution of Earth's Resources · printed p. 200 (PDF p. 236)
Processes that Shape Earth
Earth's natural resources, like minerals, energy, and groundwater, are unevenly distributed across communities.
Anchoring phenomenon
Chapters
- 16 Earth's Tectonic Plates
What evidence convinced scientists that the continents move, and how did that evidence turn a hypothesis into the theory of plate tectonics?
1 presentation10 worksheets3 labs - 17 The Rock Cycle
How does the rock cycle model the ways Earth's materials move and change, and where does the energy for each change come from?
1 presentation10 worksheets3 labs - 18 The Water Cycle
What moves Earth's water from place to place, what makes it change between solid, liquid and gas, and why can the same water end up in so many different places?
1 presentation10 worksheets3 labs - 19 Earth's Natural Resources
Why are mineral, energy and groundwater resources concentrated in some places and missing from others, and what happens to that pattern as people use them?
1 presentation10 worksheets3 labs
Standards in this unit
Unit vocabulary
hypothesisA possible explanation built on limited evidence that makes predictions you can test by observing or experimenting.Chapter 16
continental driftWegener's hypothesis that the continents were once joined in one supercontinent, Pangaea, that broke apart, with the pieces slowly moving to their present places.Chapter 16
lithosphereEarth's rigid outer shell: the crust plus the cool, stiff uppermost mantle. It is broken into tectonic plates.Chapter 16
seismic waveA vibration that travels through Earth from an earthquake. Changes in its speed and direction reveal layers that no drill can reach.Chapter 16
mid-ocean ridgeA chain of underwater volcanic mountains that winds around the globe along the places where plates move apart and new seafloor forms.Chapter 16
trenchA long, narrow valley in the seafloor, several kilometers deep, where one plate bends down beneath another.Chapter 16
continental shelfThe shallow, submerged edge of a continent, the true outline of the landmass under the water.Chapter 16
seafloor spreadingThe process in which plates pull apart at a mid-ocean ridge, molten rock rises to fill the gap and hardens, and the new seafloor moves outward on both sides.Chapter 16
subductionThe sinking of a denser plate beneath a less dense plate where the two converge, which carries old seafloor down into the mantle.Chapter 16
scientific theoryAn explanation supported by a large body of evidence from many independent lines that accounts for many observations and makes successful predictions. New evidence can still refine it.Chapter 16
plate tectonicsThe theory that Earth's lithosphere is divided into rigid plates that move slowly relative to one another, forming new seafloor at ridges and destroying old seafloor at trenches.Chapter 16
plate boundaryThe edge where two plates meet. At a convergent boundary they move toward each other, at a divergent boundary apart, and at a transform boundary they slide past each other.Chapter 16
mineralA naturally formed solid with a set chemical makeup whose atoms are packed in a repeating pattern. Most rocks are built from one or more minerals locked together.Chapter 17
textureHow big a rock's grains or crystals are, what shape they have and how they fit together; this is the main clue to how the rock formed.Chapter 17
igneous rockRock that forms when melted rock, called magma underground or lava at the surface, cools and hardens.Chapter 17
intrusive rockIgneous rock that hardened slowly below the surface, giving its crystals time to grow large enough to see.Chapter 17
extrusive rockIgneous rock that hardened quickly at the surface, so its crystals are tiny or the rock is mostly natural glass.Chapter 17
weatheringThe breakdown of rock at Earth's surface, either physically, by cracking into pieces, or chemically, by reactions that change or dissolve its minerals.Chapter 17
sedimentLoose pieces of rock, mineral grains or shells that wind, water, ice or gravity can move and later drop.Chapter 17
sedimentary rockRock made from sediment that was deposited, buried, pressed together and cemented by minerals, or from minerals that crystallized out of water.Chapter 17
metamorphic rockOlder rock whose texture or mineral makeup was changed by heat, pressure or hot fluids while it stayed solid.Chapter 17
deformationThe slow bending and squeezing of solid rock by tectonic forces, which flattens its crystals and lines them up, often in bands.Chapter 17
recrystallizationThe regrowth of the crystals inside solid rock into new or larger crystals, for example when heat flows in from nearby magma.Chapter 17
rock cycleA model of the many routes by which rock material is recycled: any rock can be weathered into sediment, changed by heat and pressure, or melted, and then become a new rock.Chapter 17
water cycleThe continuous movement of water among the ocean, the atmosphere, the land, the ground and living things, with water changing between solid, liquid and gas along the way. The Sun's energy and gravity keep it moving.Chapter 18
water vaporWater in its gas state. It is invisible. Clouds, fog and the mist above a kettle are not vapor; they are tiny liquid droplets or ice crystals you can see.Chapter 18
evaporationThe change of liquid water into water vapor at the surface of the liquid. It happens at any temperature because the fastest-moving molecules at the surface can escape, so a puddle dries without ever boiling.Chapter 18
transpirationThe movement of water from a plant's roots up to its leaves, where it evaporates inside the leaf and escapes through tiny pores called stomata as water vapor.Chapter 18
condensationThe change of water vapor into liquid water. It happens when air cools or becomes saturated, so that vapor molecules slow down and cling together, usually on a surface or on tiny particles in the air. Condensation releases energy to the surroundings.Chapter 18
crystallization (freezing and deposition)The change of water into solid ice. Liquid water freezing into ice is one kind; water vapor turning directly into ice crystals, as frost or snowflakes, is another kind that scientists call deposition. Both release energy to the surroundings.Chapter 18
sublimationThe change of ice directly into water vapor without melting first. It is why snow can shrink on a cold, dry, sunny day even though the temperature stays below freezing.Chapter 18
precipitationWater that falls from clouds to Earth's surface as rain, snow, sleet or hail, pulled down by gravity once droplets or ice crystals have grown heavy enough.Chapter 18
runoffWater that flows across the land surface, downhill under gravity, into streams, rivers, lakes and eventually the ocean.Chapter 18
infiltrationThe soaking of water from the surface down into the ground through the spaces in soil and rock, also driven by gravity.Chapter 18
groundwaterWater that fills the tiny connected spaces, called pores, between grains of soil, sand, gravel and rock below the surface. It moves slowly and can stay underground for years to thousands of years.Chapter 18
aquiferA body of sediment or rock with enough connected pore space, and enough water in it, to supply a well or a spring.Chapter 18
natural resourceA material or energy source that people take from nature and use, such as water, oil, copper ore, soil, wood or heat from inside Earth.Chapter 19
renewable resourceA resource that natural processes replace within about a human lifetime, such as surface water, a planted forest or the steady flow of heat from Earth's interior. It can still run short in a place where people use it faster than it is replaced.Chapter 19
nonrenewable resourceA resource that takes far longer than a human lifetime to form, such as petroleum, copper ore or thick fertile topsoil, so the supply shrinks as people use it.Chapter 19
sustainableDescribes a way of using a resource that leaves enough for future generations: the rate of use is no greater than the rate at which the resource is replaced or recovered.Chapter 19
groundwaterWater that has soaked into the ground and fills the pores and cracks in sediment and rock below the surface.Chapter 19
aquiferA body of porous rock or sediment, such as gravel, sand or sandstone, that stores groundwater and lets it flow well enough to supply a well.Chapter 19
rechargeThe water that reaches an aquifer by soaking down from rain, snowmelt, rivers or irrigation. The recharge rate is how much arrives per year.Chapter 19
petroleumCrude oil: a liquid mixture of hydrocarbons that formed over millions of years when the remains of tiny marine organisms were buried, heated and chemically changed deep in sedimentary rock.Chapter 19
geologic trapAn arrangement of rock layers, such as an upward fold or a fault, where a sealing layer stops rising oil and gas and holds them in a porous reservoir rock.Chapter 19
oreRock that holds a valuable mineral or metal in a high enough concentration that mining it can pay.Chapter 19
hydrothermal fluidHot water, often released by cooling magma or heated by it, that dissolves metals and carries them through cracks in rock, then leaves them behind as minerals when it cools.Chapter 19
geothermal energyEnergy from the heat of Earth's interior, carried to the surface by hot water or steam and used to warm buildings or to spin turbines that make electricity.Chapter 19