Terms Flashcards
1
Q
abrasion
A
the process of particles rubbing against each
other, wearing down the sharp edges into smaller pieces.
2
Q
absolute magnitude
A
how bright a star appears from 32.6
light years away.
3
Q
absolute zero
A
temperature at which all molecular motion
ceases (0°K, −273.15°C, or −459.67°F).
4
Q
acid test
A
tests a mineral or rock for calcite or calcium in its
composition.
5
Q
active continental margin
A
plate boundary where
mountains are formed.
6
Q
active volcano
A
volcano that has erupted in recent history
7
Q
advected fog
A
fog caused by air moving from one region to
another region with a different surface temperature.
8
Q
advection
A
movement of air from one area to another,
creating unusually warm or cold conditions.
9
Q
air mass
A
large mass of air at the surface of the Earth with
similar characteristics of temperature and humidity
throughout the mass.
10
Q
albedo
A
reflection of sunlight.
11
Q
altitude
A
angle of a celestial object above the horizon.
12
Q
anemometer
A
instrument used to determine wind speed.
13
Q
anticline
A
parallel rock layers folded upward, like an arch.
14
Q
aphelion
A
point in an orbit farthest from the Sun.
15
Q
apogee
A
point in an orbit farthest from the Earth.
16
Q
apparent diameter
A
the diameter of an object as it appears
to an observer; changes with distance.
17
Q
apparent magnitude
A
how bright a star appears to
someone on Earth.
18
Q
arid
A
climates that are extremely dry, with low precipitation
and high evapotranspiration.
19
Q
asteroid belt
A
the orbiting band of rocks between Mars and
Jupiter.
20
Q
asthenosphere
A
the outer layer of the Earth’s mantle, which
has a plastic-like composition; site of convection currents
that move the plates on the surface.
21
Q
astronomical unit
A
measurement used in the solar system,
the average distance from the Earth to the Sun
(150,000,000 km or 93,000,000 mi).
22
Q
atmosphere
A
the gas layer surrounding the Earth.
23
Q
atoll
A
ring of coral reefs surrounding a sunken island.
24
Q
aurora
A
light created in the sky by the interference of
charged solar particles with the magnetic field of the Earth.
25
autumnal equinox
September 23, when the vertical ray of
the Sun is at the Equator; the entire Earth has 12 hours of
day and 12 hours of night.
26
azimuth
direction along the horizon when looking for an
| object in the sky.
27
big bang hypothesis
says that origin of the universe was
when all matter was collected together and exploded, about
15 billion years ago
28
blue shift
```
apparent shortening of starlight as it moves
toward you (Doppler).
```
29
buoyant
describes a property that causes materials to
| appear to float in or on a fluid.
30
caldera
extinct volcano that has a collapsed cone.
31
capillary
water that works its way upward in the ground
| through adhesion to rock particles and cohesion to itself.
32
carbonates
the family of minerals composed of carbon and
| oxygen.
33
Cephid
a star that varies in its light output.
34
chemical weathering
the breaking down of rock material
| by chemical means, forming a new substance.
35
chromosphere
reddish layer of the Sun that is hydrogen
| burning.
36
cinder cone
steep cone of a volcano formed from ash and
| loose rock.
37
cirrus
very high clouds formed by ice crystals; look like
| feathers; usually associated with fair weather.
38
clastic
pieces of rock
39
cleavage
the way a mineral splits or breaks along weak
| bonds in planes.
40
climate
the overall temperature, precipitation, and weather
| conditions for an area.
41
cold front
the leading edge of a cold air mass.
42
color (as relates to ID)
an easy test in the identification of minerals, but not
| always reliable
43
column
pillar of rock formed when a stalactite and
| stalagmite merge.
44
comet
a mass of frozen gases, ice, and rock that orbits the
| Sun.
45
composite volcano
a volcano consisting of a cone of
| alternating layers of solidified lava and rock particles.
46
compound
a molecule made up of two or more elements.
47
condensation
the process of a substance changing states
| from gas to liquid.
48
conduction
transfer of energy through solids by direct
| contact.
49
constellation
a group of stars that appears to be in a
| pattern.
50
contact metamorphism
the process of changing rocks into
| metamorphic rocks by nearby magma.
51
continental glacier
a thick sheet of ice covering a mass of
land all year round, moving outward from the thickest part;
found only in Greenland and Antarctica.
52
continental rise
area which connects the continental slope
| to the ocean floor
53
continental shelf
ocean bottom along the coasts with a low
| gradient.
54
continental slope
ocean bottom that connects the
| continental shelf to the deep ocean floor
55
contour farming
planting crops along contour lines on a hill
| to help prevent soil erosion.
56
contour line
line connecting points of equal elevation.
57
convection
transfer of energy in fluids; can create currents
| by density differences.
58
converging plate boundary
region where plates move
| toward each other.
59
coordinate system
rectangular grid system for plotting
| points.
60
Nicolas Copernicus
astronomer who developed the
| heliocentric model.
61
corona
outermost layer surrounding the Sun.
62
crater
impact mark left on a planet or moon by a collision
| with a another object
63
craton
core rock base of a continent.
64
creep
slow movement of rocks and sediments down a
| hillside.
65
crust
the thin, outer layer of the solid part of the Earth.
66
crystal shape
the arrangement of molecules in a mineral.
67
cumulonimbus
cumulus cloud that builds vertically; usually
| associated with a cold front and thunderstorms.
68
cumulus
puffy, cotton-like clouds formed by rising air.
69
cyclogenesis
the process of forming storm systems.
70
deficit
time during the water budget when drought
conditions occur; there is not enough water to supply the
needs of an area.
71
delta
a triangle-shaped area of deposition located at the
| mouth of an older river.
72
density
the amount of matter in a given space.
73
deposition
the rare process of a substance changing states
| from gas directly to a solid.
74
derived unit
unit that is a combination of basic units.
75
dew point
temperature at which water vapor condenses
| into liquid water.
76
discharge
the amount of water in a river or stream that
| passes a certain point in a given amount of time.
77
diverging plate boundary
region where plates move
| apart.
78
doldrums
region along the Equator where the weather
| conditions are fairly consistent.
79
dormant volcano
volcano that has not erupted during
| recorded history.
80
drainage basin
the area around a stream that could drain
| into the stream.
81
drainage divide
the outer edge between drainage basins
82
drift
small particles carried away from larger rocks by
| glacial meltwater.
83
drizzle
liquid precipitation that is less than .02 cm in
| diameter.
84
dry adiabatic lapse rate
e rate at which dry air cools as it
| rises upward.
85
dry bulb temperature
temperature of the air.
86
dynamic equillibrium
a system that fluctuates, but overall
| is in balance.
87
El Nino, La Nina
long-term weather patterns associated
with changing global winds and ocean temperatures in the
Pacific Ocean.
88
electromagnetic spectrum
diagram that breaks down
| energy by wavelength.
89
epicenter
location on the Earth's surface directly above the
| focus of an earthquake.
90
epicycle
small circle made by a planet's orbit in the
| geocentric model.
91
equillibrium
a system that is in balance.
92
erosion
the transportation of weathered materials.
93
erratic
a large rock that is deposited by a glacier.
94
explosive eruption
volcanic activity containing thick lava
| and more gases under pressure; creates steeper cones
95
extrusive
rock that forms on the Earth's surface.
96
eye
center of circulation in a hurricane, where the conditions
| are calm.
97
eye wall
area surrounding the eye of a hurricane, where
| winds are most intense.
98
fault
a crack or break in a rock.
99
fault plane
the surface that rocks move along when plates
| shift.
100
fault block mountain
mountain range formed when
| sections of sedimentary rocks are tilted upward in sections
101
felsic
magma that is aluminum or silica based, lighter in
| color, and less dense than mafic magma.
102
fetch
length of open ocean for wind to create waves.
103
field
an area where there is a measurable amount of a
| specific value at every point
104
flood plain
the area along the banks of a meandering river
| that are prone to flooding at various times.
105
focus
exact site of the origin of an earthquake, below the
| epicenter.
106
folded mountains
mountain range formed by the collision
of continental plates, causing the rock layers to be
crumpled.
107
foliated texture
layered mineral crystals in a metamorphic
| rock.
108
fossil
evidence that life was present, preserved in a rock.
109
fracture
the uneven breaking or cracking of a mineral.
110
frost
the boundary between two air masses.
111
frost point
dew point temperature, below 0°C.
112
Fujita scale
scale for measuring the intensity of a tornado
| from F0 to F5.
113
Galileo
scientist whose observations supported the
| Copernican model.
114
geocentric
a model in which Earth is at the center of the
| universe.
115
geyser
groundwater deep in the Earth that turns to steam
and is forced to the surface when enough pressure is
generated.
116
granule
one of the individual cells that make up the
| photosphere of the sun.
117
graphical model
a graph showing relationships.
118
greenhouse effect
incoming (shortwave) energy is
reradiated as heat energy (longwave) and trapped by the
greenhouse gases in the atmosphere; causes global
warming.
119
greenhouse gas
a gas produced from burn fossil fuels,
which hold and trap heat energy; carbon dioxide is an
example.
120
ground fog
fog formed by radiational cooling.
121
guyot
flat-topped seamount, eroded by ocean waves while
| exposed.
122
hail
layers of ice formed in a large thunderstorm cloud that
| fall to Earth.
123
half life
the amount of time it takes a radioactive element
| to decay into half of its original mass.
124
heliocentric
sun-centered model of the solar system.
125
Horse Latitude
area of little surface winds and high
| pressure along 30° N latitude.
126
hot spot
weak or thin area in a plate that allows magma to
| rise up and reach the surface.
127
hot spring
groundwater heated by magma rising to the
| surface through an opening in the ground.
128
hurricane
low-pressure system with sustained winds of 74
| mph or greater.
129
hydrosphere
the water layer of the Earth.
130
hygrometer
an instrument used to measure humidity; can
| be made from hair.
131
igneous
rock formed when molten rock cools.
132
impermeable
rock that water cannot sink into or through.
133
index fossil
a fossil of an organism that occurred for a
short amount of time and over a widespread area; used to
connect rock layers over long distances.
134
inference
an educated guess based on collected data
135
infiltration
water sinking into the ground.
136
inner core
the solid center of the Earth, composed of iron
| and nickel.
137
insolation
a combination of the words incoming solar
| radiation.
138
instrument
tool used to extend your senses and gather
| data.
139
International Date Line
the longitude line measuring 180°
| where the day changes.
140
Intertropical Convergence Zone
area along the Equator
where trade winds from the Northern and Southern
hemispheres meet, forming thunderstorms.
141
intrusion
magma that crosses through other rock layers,
| cooling and hardening before reaching the surface.
142
intrusive
rock that forms below the Earth's surface
| plutonic
143
inversion
an atmospheric condition where warm air is on
| top of cold air.
144
isobar
line connecting areas of equal pressure on a map.
145
isoline
line that connects equal values.
146
isosurface
three-dimensional diagram showing surfaces
| connecting equal values.
147
isotherm
line connecting areas of equal temperature on a
| map.
148
isotopes
two elements that have the same atomic number
| but different atomic masses.
149
jet stream
band of fast-moving air in the upper
| troposphere.
150
Jovian Planet
```
outer planet (Jupiter, Saturn, Uranus, and
Neptune) consisting of a gaseous surface.
```
151
Kepler
astronomer who developed three laws
of planetary motion: planets move in elliptical orbits; planets
sweep out equal area in equal time; the period of revolution
is proportional to the distance to the Sun.
152
kettle
a steep-sided pond created by a glacier when a block
| of ice is left behind as the glacier retreats.
153
key bed
a layer in the rock record showing an event that
occurred quickly and over a widespread area; is used like an
index fossil.
154
land breeze
local wind that forms at night along a beach
due to uneven cooling rates of land and water, wind moves
from land to water.
155
lateral moraine
the pile of rocks that accumulate along the
| edges of a glacier.
156
latitude
coordinate lines for locating a position on Earth
that run east and west and are parallel to each other,
running from 0° to 90° (angle from the equator).
157
lava
liquid rock on the surface of the Earth.
158
leeward
the side opposite from the prevailing wind
| direction.
159
lifting condensation level
formula used to find the height
| at which clouds can form.
160
light year
the distance that light travels in one year, about
| 9.5 trillion kilometers.
161
lightning
electricity generated by a thunderstorm.
162
line graph
points plotted on a coordinate system and
| connected with a line.
163
lithosphere
the rock layer on the outer edge of the Earth.
164
local noon
occurs when the Sun is at its highest point for
| the day.
165
longitude
coordinate lines for locating position on Earth
that run north and south through the poles, are farthest
apart at the Equator, run from 0° to 180°, are equal in
length, and are measured from the Prime Meridian.
166
longshore current
a current moving parallel to the coast.
167
low pressure center
counterclockwise circulation center,
| formed along a stationary front in the Northern Hemisphere.
168
luminosity
actual brightness of a star.
169
lunar eclipse
the Moon goes out of view as it moves into
| the Earth's shadow; occurs during the Full Moon phase.
170
luster
the way a mineral shines in reflected light.
171
L wave
longitudinal wave created by the P-wave and Swaves of an earthquake at the surface of the Earth; these
are the slowest and move outward like ripples on a pond.
172
mafic
magma that is iron or magnesium-based, darker in
| color, and more dense than felsic magma.
173
magma
liquid rock below the Earth's surface.
174
magnetic declination
the number of degrees that a
compass needle is pulled away from True North to point
toward Magnetic North.
175
Magnetic North
the area near Hudson Bay, Canada, where
the Earth's magnetic field is strongest in the Northern
Hemisphere (location changes over time).
176
main sequence star
star that falls into broad band along
| the H-R diagram.
177
mantle
the layer below the crust; about 2,900 km thick;
| contains rocks rich in iron, magnesium, and silicon
178
maria
large, flat areas on the Moon.
179
Marianas Trench
deepest trench in the world; lies off the
| coast of Japan.
180
mathematical model
an equation representing an idea.
181
matter
anything that has mass and takes up space.
182
mechanical model
a physical model with moving parts.
183
mechanical weathering
the physical breaking down of
rock, changing only its size (smaller); examples are ice
wedging, plant action, and pressure unloading.
184
medial moraine
the moraine created when two glaciers
| meet and their lateral moraines merge.
185
mental model
an idea or model that exists in your mind.
186
mercalli scale
scale for measuring earthquakes based on
| obsevations.
187
meridiean
line of longitude
188
mesopause
region between the mesosphere and the
| thermosphere.
189
mesosphere
part of the atmosphere between the
stratosphere and the thermosphere; temperatures decrease
with altitude.
190
metamorphic
existing rock that undergoes extreme heat or
| pressure and is recrystallized.
191
meteor
a meteoroid that enters the Earth's atmosphere;
| also known as a shooting star.
192
meteorite
a meteor that reaches the surface of the Earth.
193
meteoroid
a rock fragment orbiting in the solar system.
194
mid latitude low
low-pressure system that forms along a
| stationary front.
195
mid ocean ridge
area between two diverging plates, where
magma reaches the surface and causes an area of increased
elevation and new crust along the ocean floor.
196
Milankovich period
long term climate changes due the
| wobble of the Earth's revolution around the Sun.
197
Milky Way galaxy
the spiral galaxy that includes our solar
| system near its outer edge.
198
model
a scale representation of another object or idea
199
Moh's Hardness Scale
a relative scale ranging from 1 to
10, measuring whether a mineral can scratch another
mineral.
200
moist adiabatic lapse rate
rate at which humid air cools
| as it rises upward.
201
monsoon
seasonal wind pattern changes that cause rainy
| and dry seasons.
202
moraine
large area of deposition left behind from the
| advance of a glacier.
203
natural selection
theory by Charles Darwin which states
that organisms best fit for their environment will survive and
pass along these traits.
204
neap tide
tide with the smallest tidal range; during both
| quarter phases.
205
nebula
a cloud of gas and dust in space.
206
Newton
developed the universal law of gravity.
207
nonrenewable resource
natural resources that cannot be
| replenished for millions of years, if at all.
208
normal fault
fault that occurs when rocks are pulled apart,
| causing one side to move downward.
209
oblate spheroid
the shape of the Earth; not a perfect
sphere, but flatter at the poles and slightly bulging at the
Equator.
210
observation
data that is collected through your senses.
211
occluded front
front that forms when a cold front catches
| up to a warm front.
212
orogeny
a mountain-building period or event.
213
outer core
the iron- and nickel-rich liquid layer near the
| center of the Earth.
214
outgassing
gases that escape to the atmosphere during
| volcanic eruptions.
215
outwash plain
sandy area downstream from a moraine
| created by drift particles and meltwater from a glacier.
216
overriding plate
crustal plate which collides with a more
| dense plate and moves above the plate.
217
overturning
rock layers that are flipped upside-down
| during the mountain-building process.
218
parallax
the apparent change in the position of stars due
| to Earth's revolution.
219
parallels
lines that never meet, such as latitude.
220
passive continental margin
area along the coast where
| sediments are deposited.
221
pause
a region separating two layers of the atmosphere.
222
penumbra
the lighter, gray area of a shadow.
223
percent error
formula used to find the inaccuracy of a
| measurement.
224
perigee
position in an orbit that is closest to the Earth.
225
perihelion
point in an orbit that is closest to the Sun
226
permeability
the rate at which water sinks into the ground.
227
photosphere
outer layer of the Sun.
228
physical model
l a representation of an object that you can
| hold.
229
phytoplankton
microscopic plants floating freely in the
| ocean.
230
plutonic
rock that forms below the Earth's surface
| intrusive
231
Polaris
the North Star, located in the Little Dipper
| constellation.
232
pollution
a substance that harms living organisms or the
| environment.
233
porosity
the percentage of open space between soil
| particles and rocks.
234
porphyritic texture
rocks that have different-sized
| crystals, created at different times.
235
prevailing westerlies
planetary winds between 30° and
60° latitude; they guide weather systems for the United
States (from SW to NE).
236
Prime Meridian
0° longitude line, running though
| Greenwich, England.
237
profille
side view of land on a topographic map.
238
psychrometer
an instrument with a dry-bulb thermometer
and a wet-bulb thermometer; used to measure dewpoint
and relative humidity.
239
Ptolemy
astronomer who developed the geocentric model.
240
pulsar
a star that sends energy out in pulses.
241
punctuated equillibrium
theory that organisms just
| "appear" on Earth.
242
P Waves
primary waves generated by an earthquake; these
compression waves are the fastest and travel through solids,
liquids, and gases.
243
radiation
transfer of energy through a vacuum; the way in
| which the Sun supplies the Earth with energy.
244
radioactive element
an atom that emits gamma rays,
alpha particles, and beta particles; can be used to determine
age.
245
radiosonde
weather balloon that carries instruments to
| record data and transmit readings to a base unit.
246
rain
liquid precipitation larger than .02 cm in diameter.
247
recharge
e the period of time during the water-budget cycle
| when the water in the ground is being replenished.
248
red giant
stage of the life cycle of a star in which it expands
| and cools.
249
Red Shift
```
apparent lengthening of starlight as it moves away
from you (Doppler).
```
250
regionally metamorphic
rock that undergoes intense heat
| and pressure over large areas.
251
relative humidity
a measure of how much water is in the
air compared to how much it can hold, given as a
percentage.
252
renewable resources
energy sources or other natural
| resources that are replenished shortly after being used.
253
retrograde motion
the apparent backward movement of a
| celestial object.
254
reverse fault
t rocks that crack and are thrust upward,
| forming an overhang; caused by the compression of rocks.
255
Richter scale
e scale for measuring earthquakes based on
| energy released.
256
rift erruption
lava flows in long, narrow cracks of the Earth's
| crust
257
rift valley
the space between diverging plates.
258
rip current
strong surface currents that move like small
rivers perpendicular to the shoreline, caused by water
returning from the beach to the ocean.
259
rock cycle
the continuous flow from one type of rock to
| another.
260
Saffir-Simpson scale
scale for measuring hurricane
| intensity, from Category I to Category V.
261
salinity
amount of dissolved salts in water.
262
saturated
```
cannot hold any more water, as in groundwater
or air (humidity).
```
263
scalar
field values that measure magnitude
264
scale
the proportion of a model in relation to the original.
265
scientific notation
a method of converting very large or
very small numbers into a convenient value using
exponents.
266
sea breeze
local wind that develops during the day along a
beach due to uneven heating of land and water; wind moves
from water to land.
267
seamount
underwater mountain.
268
sedimentary
rock formed from the compaction and
| cementation of fragments from other rocks.
269
seismogram
paper record graphing earthquake motions,
| created by a seismograph.
270
seismograph
machine that detects earthquakes.
271
severe thunder storm
thunderstorm that has winds in
| excess of 50 mph and can produce large hail.
272
shadow zone
area of the Earth shielded from earthquake
waves by the outer core (where S-waves are absorbed and
P-waves are refracted).
273
shield cone
broad cone of a volcano resulting from smooth
| lava flows.
274
silicates
group of minerals with silicon and oxygen as a
| base.
275
sliding plate boundary
region where plates move next to
| each other.
276
sling psychrometer
a handheld psychrometer than spins
| around, used to measure dewpoint and relative humidity.
277
slip face
the back side of a sand dune.
278
slump
rock material that is moved downhill as a block of
| land is uplifted.
279
solar eclipse
event in which the view of the Sun is blocked
by the Moon during a New Moon phase, when the Moon's
shadow reaches the Earth.
280
solar noon
the highest point of the Sun on any day.
281
solar prominence
flame-like arc extending out from the
| Sun.
282
specific gravity
the relative density of a mineral, compared
| to water.
283
specific humidity
a measure of how much water is
| actually in the air.
284
spectroscope
instrument for separating visible light into
| colors.
285
spiral galaxy
galaxy with bands of stars that rotate around
| the center.
286
spring tide
extreme tides during Full and New Moon
| phases.
287
stalactite
rock icicle forming from the ceiling of a cave.
288
stalagmite
rock formation rising up from a cave floor.
289
station model
a diagram on a weather map showing
| weather data from a specific city at a given time.
290
stationary front
initial boundary between two air masses.
291
storm surge
bubble of water carried by a hurricane,
| causing coastal flooding.
292
stratopause
the region between the stratosphere and the
| mesosphere.
293
stratosphere
the layer of the atmosphere above the
| troposphere; temperature increases with altitude.
294
stratus
layered, sheet-like clouds, usually associated with
| warm fronts and found at lower altitudes.
295
streak
the color of the powder left behind when a mineral is
| rubbed along an unglazed porcelain tile.
296
striations
parallel scratches on the Earth's surface caused
by rocks dragged by a glacier; the scratches point in the
direction of the glacial movement.
297
strike slip fault
a fault where rock plates move horizontally
| to each other.
298
subducting plate
crustal plate which collides with another
| plate and moves under it.
299
sublimation
the rare process of a substance changing
| states from solid directly to a gas.
300
subsidence
land sinks into the sea; opposite of uplifting.
301
summer solstice
June 21, when the vertical ray of the Sun
is at the Tropic of Cancer (23.5° N latitude), and is the
longest day of the year in the Northern Hemisphere.
302
sunspot
cooler area on the surface of the Sun
303
supercell
l thunderstorm with strong updrafts that exist for
| hours and can spawn tornadoes.
304
supernova
the explosion of a star
305
surplus
the period of time when the precipitation exceeds
the needs for an area and the ground is saturated; runoff
occurs, causing flooding conditions.
306
S-waves
secondary waves created by an earthquake; these
shearing waves move at right angles to the path of travel
and are stronger than P-waves, but only move through
solids.
307
syncline
parallel rock layers folded downward in a valleylike formation.
308
talus
a pile of rocks at the bottom of a hill.
309
terminal moraine
a moraine created at the end of the
| advance of a glacier.
310
terrane
large pieces of rock that are moved large distances;
| can be from another plate.
311
terrestrial planet
```
inner planet (Mercury, Venus, Earth, and
Mars) with a rocky surface.
```
312
thermocline
zone in water where the temperature changes
| drastically.
313
thermosphere
uppermost layer of the atmosphere;
| temperatures increase with altitude.
314
thinskinned thrusting
thin, horizontal sheets of rock from
| the edge of a continent are forced inland.
315
till
an unsorted pile of sediment left behind when a glacier
| melts.
316
topographic map
map that shows elevations above sea
| level.
317
tornado
narrow, funnel-shaped column of wind created by a
| thunderstorm.
318
trace fossil
evidence that life existed in the past, such as
| footprints and burrows.
319
trade winds
planetary winds between 0° and 30° latitude.
320
transform plate boundaries
region where plates move next
| to each other.
321
transparent
light can pass through the substance.
322
trench
a deep canyon in the ocean caused by a plate being
| subducted under another plate.
323
tropical depression
strong low-pressure system formed in
| low latitudes.
324
tropical storm
low-pressure system with sustained winds
| from 39 to 73 mph.
325
tropopause
region between the troposphere and the
| stratosphere.
326
troposphere
lowest level of the atmosphere, where
| weather occurs; temperature decreases with altitude.
327
True North
geographic North Pole, latitude 90° N.
328
tusnami
a large wave created by an underwater earthquake
| or landslide.
329
turbidity currents
undersea mudslides.
330
umbra
the darkest part of a shadow.
331
unconformity
a break or gap in the rock record where
| layers of rock have been eroded.
332
universal law of gravity
formula that measures the force
| of gravity; developed by Isaac Newton.
333
updraft
wind current moving upward in a cloud.
334
upwelling
deep ocean water is pulled to the surface by
| currents.
335
urban heat island effect
city areas are warmer than
suburbs or rural areas due to less vegetation, more land
coverage and other infrastructure.
336
usage
time in the water budget for an area when water is
| being used faster than it is being replenished.
337
valley glacier
a glacier located on top of a mountain, also
called an alpine glacier, that moves downhill through the
valley.
338
vaporization
the process of boiling.
339
varve
alternating layers of sediment showing yearly cycles.
340
vector
field quantity that measures magnitude and
| direction.
341
Vernal equinox
March 21, when the vertical ray of the Sun
is at the Equator; the entire Earth has 12 hours of day and
12 hours of night.
342
vertical ray
radiational energy from the Sun that strikes the
| Earth at a right angle.
343
vesicular texture
rock that has gas pockets and air that
| was trapped during the rock's formation.
344
waning
part of the lunar cycle in which the Moon is getting
| less full and the "left side is lit up" (left side lit).
345
warm front
the leading edge of a warm air mass.
346
water table
the surface of the water in the zone of
| saturation.
347
waxing
part of the lunar cycle when the Moon is getting
| more full, and the "right side is lit up."
348
weathering
the physical or chemical breaking down of
| rocks due to exposure to the atmosphere.
349
wet bulb depression
difference between wet-bulb and
dry-bulb temperatures, used to find relative humidity and
dew point temperatures.
350
white dwarf
final stage of a star as it collapses onto itself.
351
windward
the side facing the wind.
352
Winter solstice
December 21, when the vertical ray of the
Sun is at the Tropic of Capricorn (23.5° S latitude), the
shortest day of the year in the Northern Hemisphere.
353
zenith
the point directly overhead of an observer.
354
zone of accumulation
upper level of a glacier where more
| snow falls than melts.
355
zone of aeration
area underground above the water table
where the spaces between rocks contain a mixture of air and
water.
356
zone of saturation
area underground where the spaces
| between rock particles are filled with water.
