Physical science {earth science} can be about erosion, tectonic processes, terrain, and rocks.
Drills {drilling} have gone one mile below ocean floor and five miles below continents, to sample rocks.
Lowland areas have no gravity decrease {isostatic compensation}, because lowland areas have thin crust, with mantle closer to surface. Mountain areas have no gravity increase, because mountains float on mantle, pushing heavier mantle aside.
The figure eight {analemma} on globes shows Sun declination for day of year.
Earth locations use lines {longitude}| {meridian} running from pole to pole. Longitude is in degrees, up to 180 degrees east or west from the prime meridian that runs through Greenwich, England.
At meridian 180 degrees east or west {International Date Line}|, time adds one day if traveling east, and time subtracts one day if traveling west.
The reference meridian {prime meridian}| runs through Greenwich, England, at zero degrees longitude.
Earth locations use lines {latitude, Earth}| parallel to equator. Latitude is in degrees. Equator is 0 degrees latitude. North Pole is 90 degrees north latitude. South Pole is 90 degrees south latitude.
The reference latitude {equator}| runs horizontally around Earth middle and is zero degrees latitude.
People cannot see Sun in winter in Southern Hemisphere above 66.5 degrees south latitude {Antarctic Circle}|.
People cannot see Sun in winter in Northern Hemisphere above 66.5 degrees north latitude {Arctic Circle}|.
Sunlight falls straight down on Midsummer Day at 23.5 degrees north latitude {Tropic of Cancer}| in Northern Hemisphere.
Sunlight falls straight down on Midsummer Day at 23.5 degrees south latitude {Tropic of Capricorn}| in Southern Hemisphere.
Zones {semitropics}| can be between tropic and temperate zones.
Earth climates {climate}| {clime} can be wet or dry.
dry
Deserts and steppes are 25% of Earth land area. Deserts and steppes have large yearly and daily temperature variation, have rain in summer if at high altitude, have rain in winter if at low altitude, and have high winds.
wet
Pacific Ocean surface currents typically make monsoons. With warm El Ni-o, west North America has wet weather.
wet: plants
Plants absorb rain in roots and evaporate water from leaves, allowing rain to form and fall in one place. If plants die, water goes into ground, and rain is less.
core and surface temperature
Heat flow from core has no effect on Earth surface temperature.
Tropical winds push warm water north along east North-American coast {conveyor belt}. It becomes denser at it cools and sinks near Greenland, allowing flow to continue. Europe receives warm water that returns south in deep water along east Atlantic Ocean. If melted snow enters North Atlantic, the cold fresh water prevents warmer salty water from sinking, and conveyor belt turns off. Cold, dry winds flow east around north.
Above 4000 to 6000 feet is line {forest line}| where forest stops.
Temperate climates can have summer-like weather {Indian summer}| in fall.
Earth receives radiation {insolation}| from Sun. As Venus, Jupiter, and Saturn have different relative positions, Earth orbit varies, which changes insolation. Sun can brighten and darken, changing insolation.
Earth radiates heat {heat radiation}. Soot, particles, and clouds {aerosol, atmosphere} affect heat radiation.
Chemicals can prevent heat from escaping Earth {greenhouse effect} {global warming}|. Carbon dioxide, methane, ozone, nitrous oxide, and chlorofluorocarbons (CFC) prevent heat radiation from Earth by absorbing infrared radiation. Methane comes from gas and oil wells, landfills, and waste processing. Carbon soot and other dark pollution particles trap heat.
reflective
Sulfate aerosols are reflective and prevent insolation. Clouds affected by aerosols are brighter, last longer, are reflective, and prevent insolation. Volcanoes add soot that blocks sunlight.
ocean
Ocean absorbs excess heat.
forests
Deforestation reduces dark areas and reduces heat absorption.
speculation
Ships with windmills can hydrolyze seawater in windstorms or in normal winds to make and store hydrogen and oxygen, as well as upwell cold seawater from the deep to cool hot spot.
Carbon dioxide, chlorofluorocarbons, ozone, nitrous oxide, and methane {greenhouse gas}| prevent heat radiation from Earth by absorbing infrared radiation.
If ice starts to form on Earth, it reflects more light, Earth gets icier, and water in air becomes less {White Earth climate}, while carbon dioxide forms into carbonates at equator. Perhaps, an Earth ice covering reflected light and kept Earth cold for 10 million years, with no rainfall, dry winds, no water vapor, and low carbon dioxide. Volcanoes release carbon dioxide can warm Earth again over the ten million years, because carbon dioxide does not go into plants or carbonates in cold weather.
Above 4000 to 6000 feet, climate {highland climate}| has low air pressure, low humidity, large daily temperature range, large annual temperature range, and no forests.
More evaporation than precipitation causes very dry climate {arid climate}|.
Arid climates {desert}| can have cactus and bushes.
More evaporation than precipitation causes dry climate {semiarid climate}.
Semiarid climates {steppe}| can have grass.
Humid rainy climate {tropical}| near equator has narrow temperature range, average temperature greater than 65 F, and dry winters if on west coast.
Seasonal humid climate {subtropical}| at 25 to 40 degrees latitude has dry summers if on west coast.
Humid climate {temperate climate}| at 40 to 60 degrees latitude has summer rainy season and rapid weather changes. It has Indian summers, January thaws, blizzards, and heat waves if on east coast or in interior. It has small temperature range if on west coast.
At 50 to 65 degrees latitude, climate {boreal}| has long cold winters, large annual temperature range, small precipitation in summer, targa, permafrost, long winter nights, long summer days, many lakes, and little topsoil.
Boreal climate has regions {targa}| with sparse conifer forests.
Boreal climate has frozen subsoil and rock {permafrost}|.
At 65 to 90 degrees latitude, cold climate {polar, climate}| has no forest, no sunlight for six months, large annual temperature range, little rain, ice caps, and tundra. Ice caps are 8% of Earth surface.
Polar climate has land {tundra}| with small and sparse vegetation.
Earth layers {planet layer} are core, mantle, and crust.
Earth center {core, Earth} {Earth core} has been the same since 3,500,000,000 years ago, after heating and layering ceased.
Earth center {inner core, Earth} is solid iron with some nickel and cobalt. Inner core has pressure 20,000 tons/in^2, temperature 4000 F to 8000 F, and radius 800 miles.
Layer {F shell} above inner core is 300 miles thick.
Layer {outer core} above F shell is liquid iron with some nickel, cobalt, silicon, and sulfur. Outer core has pressure 10,000 tons/in^2 and is 1375 miles thick.
Layer {D shell} above outer core is several hundred miles thick.
Above core D shell is layer {mantle, Earth}|. Mantle is 1800 miles thick and contains 80% of Earth volume.
temperature
Mantle temperature at 500,000 meters deep is 2300 K. Mantle temperature at 100,000 meters deep is 1500 K. Temperature increases with depth, 1 C every 30 meters. Lower mantle, below 700,000 meters deep, has convection currents caused by heat.
density
Below 650,000 meters deep, density is 5.5 g/cm^3. Between 400,000 to 650,000 meters deep, density is 4.5 g/cm^3. Above 400,000 meters deep, density is 3.5 g/cm^3. In upper mantle, which is 50 miles thick, density is 2.6 g/cm^3.
rock types
Lower mantle has dunite, which is mostly olivine, with some peridotite. Olivine has magnesium, silicon, and oxygen. Upper mantle has serpentine, at 50 miles to 100 miles above olivine, where 0.1% water and some carbon dioxide change olivine and pyroxene into serpentine and hydrogen {serpentinization}.
Iron and magnesium silicate olivines are 100,000 meters to 250,000 meters deep, in lower upper mantle {asthenosphere}.
Iron and magnesium silicates {dunite} are mostly olivine and make lighter-color veins in upper mantle.
Iron and magnesium silicates {eclogite} are in mantle.
Above Mohorovicic discontinuity is surface layer {crust}|.
Layer {Mohorovicic discontinuity} above mantle is thin.
Upper-mantle serpentine layer and lower-crust sial layer make layer {lithosphere}.
Lower crust is a three-mile thick heavy iron-and-magnesium-silicate basalt layer {sial layer}. Basalt forms from melted upper-mantle serpentine under lower pressure. Basalt crust density is 2.3 g/cm^3.
Upper crust has landmasses {continent, land}|. Continents now cover 25% of Earth surface. Continents average 20 miles thick and can be 40 miles thick. True continent edge is below ocean at continental-shelf edge, up to 400 miles from shore.
rocks
Continental rock is permanent, with no recycling back into crust or mantle. Continents are mostly granite, with density 2.1 g/cm^3 {sima layer}, so they rise above seas.
formation
First continent rocks appeared 4,000,000,000 years ago, as continents grew from upper mantle. After first continent-formation period ended 3,500,000,000 to 3,800,000,000 years ago, continents were 5% to 10% of crust. First-formation-period rocks are in Isua in southwest Greenland. These rocks have greenstone belts, granite-gneiss terrains, or igneous rocks cutting through them from upper mantle. Greenstone belts contain ultramafic rock and mafic rock, as xenolith.
Second continent-formation period, from 2,600,000,000 to 2,900,000,000 years ago, formed 50% to 60% of continental Archean rock.
Third continent-formation period was 1,700,000,000 to 1,900,000,000 years ago.
Fourth continent-formation period was 900,000,000 to 1,100,000,000 years ago.
Fifth continent-formation period was 600,000,000 years ago.
Igneous rock {mafic rock} can be mostly iron and magnesium. Mantle basalt, ocean-floor bedrock, and lava are mafic.
Greenstone belts contain volcanic rock {ultramafic rock} and partially melted mafic rock, which have no water.
Greenstone belts contain ultramafic and mafic rock, which have no water {xenolith}.
The second continent formation period, from 2,600,000,000 to 2,900,000,000 years ago, formed 50% to 60% of continents {Archean rock}.
Continent has independent masses {subcontinent} that have come together by plate movement.
Earth has magnetic fields {magnetic field, Earth} {Earth magnetic field}, because thermal convection from iron-solidification latent heat and escape of inner-core iron oxide and iron sulfide causes liquid-iron outer-core spin {geodynamo}. Magnetic-field strength is 10,000 gauss at Earth surface. Magnetic field is decreasing. Magnetic field reverses polarity randomly, approximately every 250,000 years. Earth magnetic field has had same polarity for last 780,000 years.
Earth has magnetic equator {aclinic line} between magnetic poles.
Ions from Sun can enter Earth atmosphere at poles, along magnetic-field lines. They hit atmosphere atoms and make light displays {aurora, pole}| that look like colored curtains, at North Pole {aurora borealis} {northern lights} or South Pole {aurora australis}.
Earth has magnetic poles {magnetic pole, Earth}|. Magnetic North Pole is in north Canada, not at spin North Pole.
From 600 to 40,000 miles above Earth surface, magnetic fields {magnetosphere} {Van Allen radiation belt} deflect weak cosmic rays and absorb ions from Sun. Sun ions push magnetosphere out from Sun.
Meteoroids can enter Earth atmosphere and heat until they make light {meteor}|. Every year, Earth adds 1000 to 1,000,000 tons of meteor dust.
Stony meteorites can have tiny olivine and pyroxene clumps {chondrule}.
Stony meteorites {chondrite} can have olivine and pyroxene chondrules. Stony chondrites are 90% of all meteorites.
Stony meteorites {achondrite} can have no clumps.
Space objects {meteoroid}| can be broken-planet pieces from asteroid belt.
Meteors {meteorite}| can hit ground. Largest meteorite weighed 30 tons. A 15,000-ton meteorite formed Canyon Diablo Meteor Crater, 4100 feet across and 600 feet deep, in Arizona. Meteorites {iron meteorite} can have more than 98% iron and nickel. Meteorites {stony iron meteorite} can have 50% nickel-iron and 50% olivine. Meteorites {stony meteorite} can be mostly rock, with little nickel and iron.
Early Moon meteoroid impact melted glass, which splashed up and then landed on Earth in a strip of achondrite drops {tektite}|.
Continental plates move {plate tectonics}|, when olivine from upper mantle comes through rift in crust basalt, pushing plates apart. See Figure 1.
Plates can slide into each other, pushing one down and one up to make trenches and mountains. See Figure 2.
rates
Pushed plates move two centimeters per year. Sea-floor movement in Chile is 15 centimeters per year.
results
Upwelling at ocean ridges can make volcanoes with basalt lavas. Old rift valleys can fill with aulacogens.
evidence
Coal is in Antarctica. Similar fossils are on separated continents. All over world, iron in volcanic rocks aligns in many different directions, instead of only north and south. East South America and west Africa have similar coastlines.
Sea floor is spreading away from Mid-Atlantic Ocean Ridge. Basalt at Mid-Atlantic Ocean Ridge is younger than basalt near continents. Mid-Atlantic-Ocean Ridge basalt shows alternating iron-particle orientations every 700,000 years, when Earth magnetic field reversed. Sediment at Mid-Atlantic Ocean Ridge is less than at continent edges.
Pacific-Ocean floor has thicker sediments and is older than Atlantic-Ocean floor. Atlantic-Ocean floor is 200,000,000 years old. Atlantic-Ocean sediment averages only several thousand feet thick and in some places is much thinner. If ocean floor had not changed for 200,000,000 years, sediment would be several miles thick.
Six major, and many minor, crust pieces {continental plate} {crustal plate}| float on upper mantle.
Continental plates move when olivine from upper mantle comes through basalt crack {rift}|, pushing plates apart. Pushed plates move one inch per year. Atlantic-Ocean middle has rift north to south that rises above sea level at Iceland, Azores, and Ascension Islands. Southeast South Pacific Ocean and central Indian Ocean have rifts.
Old rift valleys can fill with sediment {aulacogens}.
Along rift, lava makes mountain ridge, with valley down middle {sea floor spreading}|.
Continent granite {shield, continent}| can be at surface.
Rock layers can have shape like upside-down V {anticline}.
Rock layers can bend up or down {monocline} {flexure}.
Rock layers can have shape like V {syncline}.
Slips along rock faults cause movements {earthquake}|. Slow plate movements and collisions lead to sudden shifts of one plate against the other. Earthquakes can be several miles deep or even in mantle under ocean trenches. After earthquake, Earth vibrates at low frequency for several days. About 20 major earthquakes and 10^6 minor ones happen each year. Major earthquakes have been in China 1976, Tokyo 1923, San Francisco 1906, Lisbon 1755, Calcutta 1737, and China 1556.
Rock has big cracks {joint, rock}.
Earthquakes can be along rock fractures {fault}|.
Instruments {seismograph}| can measure Earth movements.
Seismographs can use logarithmic scales {Richter scale}|, from 1 up. Largest earthquake was 8.5.
Earthquakes {silent earthquake} can be slow and quiet. Perhaps, water percolation from rain or from trapped water in rocks causes them.
Earthquake shaking can cause loose wet sandy soil to become like quicksand {soil liquefaction}|.
Earthquakes under ocean can make fast waves, which then slow near shore and bunch to make towering waves {tsunami}|.
Earthquake shocks can travel through crust as slow surface waves or through Earth interior as very fast primary waves {P wave}.
Earthquake shocks can travel through solids as fast secondary shock waves {S wave}.
Both horst and graben processes form mountains {orogeny}.
Mountain building processes can make large lowered masses {graben}|, as in Death Valley USA, Red-Sea basin, and East-Africa rift valleys.
Mountain building processes can make large raised masses {horst}|, as in Sierra Nevada Mountains and Alps Mountains.
Upper-mantle convection currents rise near surface at 20 locations {plume, mantle} {hot spot, mantle}|. Plumes have 300,000 meters diameter. Plumes in crustal-plate middle can send alkali-rich basalt lava up to surface to form volcanoes, as in Hawaiian Islands.
Colliding plates can move straight into each other {pressure ridge} to make mountains, with no overriding. Alternatively, one plate can slide over other one, forming both mountains and ocean trenches.
Along rift, lava makes mountain range {ridge, mountain}|, with valley down middle.
At plate sides opposite from rifts, plates slide under other plates {subduction, plate}|. Plates meet {subduction zone}, and one plate goes up and the other goes down, at 45-degree angles. Plates can go 700 kilometers into mantle. Subduction is at North-America and South-America west coasts, at Asia east coast, and from Spain and north Africa to Italy, to Greece, to Turkey, to India, to Burma, to Celebes.
Ocean crust and underlying mantle {ophiolite} can uplift onto continent.
Colliding plates can make especially deep and steep ocean floor {trench}|.
Continents move on upper mantle {continental drift}|. Upper-mantle asthenosphere and possibly all mantle has stable constant one-inch-per-year convection currents, caused by heat. Currents provide energy to move continents. Continents have been drifting for last 2,000,000,000 years. Six major and many minor crustal plates float on upper mantle.
Plate movements make crust slide, fold, and fault {diastrophism}.
Increased fluid pressure, changed electrical resistivity, decreased Earth natural electric currents, increased deep-well-water radon content, changed seismic-wave travel time, and seismicity affect crustal-plate movements {dilatancy}. Dilatancy models earth movements as inelastic swelling. Steady stress increase splits crust, allowing water flow. If water flows in slower than cracks open, crust splitting slows. Then water under pressure quickly fills crack, causing sudden slip. Changes from compression waves to shear waves cause seismic-wave travel-time changes.
Continents are 10% lighter than crust, and crust is 10% lighter than upper mantle, so continents float on crust, which floats on upper mantle {isostasy}.
Plate movements {tectonic process}| make crust slide, fold, and fault in diastrophism.
Magma comes from mantle, 2 to 100 miles down, to surface {volcano}| through crust fissures. Magma then cools and hardens. Most of Earth water vapor and gases came from volcano eruptions.
types
Thick magma has more gas, is red hot, erupts explosively, and makes steep mountains. Thin magma has little gas, is white hot, and makes wide mountains.
examples
Famous volcanoes are Mount Vesuvius in Italy, which buried Pompeii [79]. Krakatoa in Indonesia exploded island [1869]. Mount Etna in Italy caused enormous avalanche and undersea mudslide [-6000] and started a huge tsunami: it is still active. Mauna Loa in Hawaii is active.
Volcanoes can erupt {volcanism} where plates collide, making andesite lava.
Magma can spread to make stock rock masses, which can be thousands of square miles wide {batholith}.
Volcano tops have craters {caldera}|.
Magma can flow into vertical rock fissures and cool and harden {dike, magma}.
Cylindrical columns {kimberlite pipe} from mantle to crust can have 300-meter diameter.
Magma {lava}| can reach surface.
Molten igneous rock {magma}|, mixed with gas and water vapor, comes from mantle, 2 to 100 miles down, to surface through crust fissures.
Magma can make underground pools {sill, magma}.
Magma can spread to make large rock masses {stock, rock}.
Earth temperature {temperature, Earth} increased until 130,000,000 years ago, then decreased until Ice Ages, and has remained almost the same since then. The year -8000 was warmest in recent history, until 20th century. Climate has been slowly cooling since then. Sea can rise or fall by 400 feet between Ice Age and warm period. Increased-volcanic-eruption periods correlate with Ice Ages, because volcanic dust reflects more sunlight and makes Earth cooler.
Strata can contain organic molecules {biomarker} from organism classes, because some cell-membrane lipids do not decompose.
Carbon isotopes are carbon-12, carbon-13, and carbon-14. Photosynthetic plants use more carbon-12 than carbon-13, so abundant plants lower carbon-12 ratio {isotope ratio, carbon} {carbon isotope ratio} in air. Air trapped in ancient rocks and ice can show relative amounts of photosynthetic plant life at past times.
Large meteors or comets and high volcanism can cause widespread death {catastrophe, Earth}.
meteor
Large meteor or comet hit 65 million years ago. Iridium level is higher in that rock stratum than in other layers. Iridium is more abundant in space than on Earth. That stratum also has pressure-shocked minerals.
volcanoes
Volcanic activity was high 443 million years ago, 374 million years ago, 251 million years ago, and 201 million years ago. Volcanoes put hydrogen sulfide, sulfur dioxide, carbon dioxide, and methane into air, which cause greenhouse effect and warm air.
ocean
With ocean warming, surface absorbs less oxygen, and chemocline rises. At high enough warming, chemocline comes to surface, and hydrogen sulfide enters air. Hydrogen sulfide kills land animals and plants directly. It also attacks ozone shield, allowing more UV radiation, which kills animals and plants.
Water absorbs oxygen. Water absorbs less oxygen at higher temperature, so oceans have less oxygen at surface and more at lower depths, which are cooler. At ocean bottoms, hydrogen sulfide comes from thermal vents. It rises and prevents further oxygen absorption at ocean depth {chemocline}. Below chemocline is high hydrogen sulfide, and above chemocline is high oxygen. Green sulfur bacteria and purple sulfur bacteria use hydrogen sulfide and are near ocean bottom. Photosynthetic organisms use dissolved carbon dioxide and sunlight so they stay near surface. Zooplankton use oxygen and so stay above chemocline.
Glaciers are largest every 100,000 years {glaciation era}, when Earth-axis tilt toward Sun minimizes, and perihelion shortest distance from Earth to Sun is in December in Northern Hemisphere, which has more land. Glaciers are smallest every 100,000 years, when Earth-axis tilt toward Sun maximizes, and perihelion shortest distance from Earth to Sun is in June in Northern Hemisphere, which has more land.
Continental {land mass} drift affects Earth temperature. When more land is in tropics, Earth absorbs more heat. When less land is at poles, glaciers decrease, reflective ice is less, and Earth reflects less heat.
Earth-axis tilt, axis wobble, and orbit cycles change sunlight amount that falls on Earth, in an overall cycle that caused Ice Ages {Milankovich model}. Earth-axis tilt cycles over 90,000 to 100,000 years. Earth axis wobble has a 39000-year to 42000-year cycle. Earth orbital path has a 17000-year to 21000-year cycle. Summer in Northern Hemisphere can be when Earth is closest to Sun, making hotter land temperatures.
Earth gases {atmosphere, Earth} are five miles thick at poles and ten miles thick at equator. Carbon dioxide and water absorb infrared radiation. Ground absorbs infrared, because it has water and wet dirt. Atmosphere layers are troposphere, tropopause, stratosphere, mesosphere, D layer, E layer, ionosphere, F layer, G layer, exosphere, and magnetosphere.
Warm air can flow and warm cold air {advection radiation}.
Jet airplanes leave water-drop or ice-drop white lines {contrail}|.
sky {firmament}|.
If sunlight from behind observer hits air water droplets, droplets act like prisms and spread sunlight into color spectrum {rainbow}|.
sky {welkin}.
Water vapor can condense on sea salt, dust, smoke particles, volcanic ash, or nitrous oxide, to make drops one millionth raindrop size {cloud}|. Nitrous oxide forms by lightning. Tiny drops coalesce. When big enough, they drop. Fine raindrops come from low clouds, and big raindrops come from high or thick clouds. Clouds are white if water density is small and are dark if water density is great. Cloud shapes depend on fronts that make them.
Cloud-cover lower side has altitude {ceiling}|. Above ceiling is limited visibility.
Light and dark clouds {mackerel sky, cloud}| indicate rain.
Upper-atmosphere dust and clouds reflect 30% of solar energy {reflectance, atmosphere}. Ozone, dust, and clouds absorb 20%. Ground absorbs 50%.
Dry ice and silver iodide crystals {seeding}| in clouds can cause rain or reduce fog.
Cold fronts can make dark-cloud lines {squall line}|, from which can come tornados or waterspouts.
Warm front first makes cirrus clouds, then cirrostratus clouds, then gray clouds {altostratus cloud}, and then nimbostratus clouds.
Warm front first makes cirrus clouds, then wispy clouds {cirrostratus cloud}, then altostratus clouds, and then nimbostratus clouds.
Clouds {cirrus cloud}| can be white, feathery, and 4 to 8 miles high.
Cold front first makes high and thick clouds {cumulonimbus cloud} and later makes dark, low clouds and small strong storms.
Clouds {cumulus cloud}| can be billowy, deep, fluffy, white, and one mile high.
Warm front first makes cirrus clouds, then cirrostratus clouds, then altostratus clouds, and then low, thick, dark clouds {nimbostratus cloud} with broad light rain.
Clouds {nimbus cloud}| can be gray or dark.
Clouds {stratus cloud}| can be flat, scattered, low or high, and white or gray.
Mirages {fata morgana}| can be high in sky, unrelated to surface conditions.
Brilliant green or blue light {green flash}| can flash at sunset, by prism effect. Prism effects cause Sun to appear flattened and/or irregular on horizon.
Atmosphere refraction bends light rays, so light seems to come from ground {mirage}|, instead of from sky. Temperature differences, with hotter air closer to ground, cause mirages.
Still warm-air layer can lie under cool air {air inversion}|.
Humid air can cool to temperature {dew point} at which water condenses.
Water can condense on ground {dew}|, instead of in air, when ground is cooler than air, often after midnight on still autumn nights.
In air inversion, ground can lose heat by radiation at night and condense water {fog}| from warm air. Warm air cooled by rain can condense water and make fog.
Dew {frost}| can freeze.
Frost {hoarfrost}| can form on artificial surfaces.
Air layer {troposphere} next to surface has 3/4 of all air and has all clouds, dust, wind, and storms. Surface pressure is 15 lb/in^2. Average surface temperature is 63 F. At troposphere top, temperature is -60 F to -100 F. Troposphere is 78% nitrogen, 21% oxygen, 2% average water vapor, 0.9% argon, and 0.03% carbon dioxide. On hot humid days, water vapor can be 3% or 4%.
Above troposphere is a boundary layer {tropopause}.
Above tropopause, a 10-to-15-mile-thick layer {stratosphere}| has temperature -60 F to -100 F. Lower part is sulfate layer. Higher part is ozone layer. Ozone absorbs ultraviolet rays from Sun.
Above stratosphere, a 25-to-35-mile-thick layer {mesosphere} has temperature 50 F.
Above mesosphere is an ionized boundary layer {D layer}.
Above D layer is a dust belt {noctilucent cloud}, with high thin clouds visible at night.
Above dust belt is an ionized boundary layer {E layer} {Heaviside layer}.
Above E layer, a 300-to-550-mile thick layer {ionosphere} has temperature 2000 F. It contains mostly oxygen ionized by x-rays and ultraviolet rays. It reflects short-wave radio waves.
In ionosphere is an ionized layer {F layer}.
Above ionosphere is an ionized boundary layer {G layer}.
Above G layer {exosphere} contains mostly helium for 900 miles and then mostly hydrogen for 4000 miles and has magnetosphere.
Electric discharges {lightning}| can go between clouds or between clouds and ground. Strength can be 10^8 volts. Lightning strikes 44,000 times a day and makes 200 forest fires a day. Lightning can be streaks or sheets. Rare lightning form is hot ionized gas {ball lightning}. Lightning makes nitrous oxide, which fertilizes soil.
process
As warm air rushes up and raindrops fall, they rub each other and separate charges, making voltage. If charge path is between cloud and ground or another cloud, first a thin current streak {leader, lightning} flows, followed by main discharge at more than 1000 amperes for 10^-2 seconds.
Metal conductors {lightning rod}| can conduct lightning current into ground, to dissipate it.
Lightning heats air suddenly and expands it rapidly, making noise {thunder}| as shock waves. People can hear thunder up to 15 kilometers away.
Lightning can make radio waves {whistler}| that strike magnetosphere and come back along magnetic-force lines. High frequencies come back first, followed by low frequencies.
Lightning {blue jet} can flash between upper clouds and ionosphere, 44 to 50 miles away, in tree-like structure.
Far-away lightning reflections {heat lightning} can be on horizon clouds on hot summer evenings. Thunder is too far away to hear.
Lightning can cause mushroom-shaped flashes {red sprite} in ionosphere.
Water returns to ground from clouds as rain, sleet, hail, or snow {precipitation, weather}|. Pressure changes and wind surges cause storms in tropics. Above tropics, fronts cause precipitation.
Yearly rainfall {rain}| averages 30 inches per year. Sea precipitation averages 44 inches per year. Land precipitation averages 26 inches per year. 25% goes into rivers, and 75% is on land.
When frozen raindrops pass through thunderstorm, they {hail}| pick up snow and ice.
When raindrops pass through very cold air, they {sleet}| can freeze.
If clouds are 0 C, snowflakes {snow, precipitation} form. Snowflakes have thin surface unfrozen-water film, which makes them stick to other snowflakes in special ways. That is why snowflakes are always hexagons. Snow can fall only above latitude 30 degrees. One foot of snow equals one inch of rain.
water-saturation percentage {aridity}|.
Air water decreases with humidity and increases with temperature and wind speed {evaporation}|. Latitudes from 10 to 40 degrees have more evaporation than precipitation, and lose heat. Other latitudes have more precipitation than evaporation, and gain heat. Oceans have more evaporation than precipitation. Land has more precipitation than evaporation.
Air can hold variable water amounts {humidity}|. Water in air is 0% to 4%.
measurement
Humidity can be water mass in air mass {specific humidity}. It can be water mass in air volume {absolute humidity}. It can be water vapor mass compared to maximum amount possible at that temperature and pressure, expressed in percent {relative humidity}.
levels
Relative humidity is most comfortable at 50%. High humidity makes cold air feel colder and warm air feel warmer. High temperatures feel cooler if humidity is lower. Higher humidity makes temperature feel higher or lower, because water does not evaporate from skin as easily.
altitude
Humidity is highest at surface and decreases greatly with altitude.
latitude
Humidity is highest at equator and decreases toward poles.
time of day
Humidity increases at night as air cools. Humid air can cool to dew point.
air pressure
More water in air makes lower air pressure, because water molecules weigh less than average air molecule. Wet days have low air pressure. Dry days have high air pressure.
Human-hair-length change {hygrometer}| can measure humidity.
Signs {weather sign} that forecast fair weather are evening rainbow or deep-blue sky color, even between clouds. Signs that forecast rain are gray and lowering sunset, green or yellow-green sky at sunset, red sunrise with clouds lowering later, sun dog around Sun or Moon after fine weather, morning rainbow, or sky whiteness. Clouds that look like lenses indicate high winds. Light and dark clouds {mackerel sky, weather} indicate rain. Low dark clouds indicate stormy weather.
Prolonged air contact with surface gives air {air mass}| same temperature and humidity as surface. Air masses {tropical mass} over Sahara Desert are warm and dry. Tropical masses in tropics are warm and wet. Air masses {polar mass} over plains of Canada or Siberia are cold and dry. Cold air masses make high pressure. High-pressure air masses can stay offshore, blocking east-west wind flow.
Atmosphere pressure {air pressure}| depends on temperature, water content, friction, centrifugal force, and flow. Cooler air has higher pressure. Spinning air can have higher pressure. Air with less water has higher pressure. Air blocked by mountains has higher pressure. Air-pressure patterns vary by latitude. High-pressure swirling cells are more near poles and in subtropics. Low-pressure cells are more in temperate zones.
Difference, between average daily temperature and 20 C, times number of days in month {degree-day}, directly relates to fuel to use to keep warm.
Warm air mass makes low pressure {depression, atmosphere}|, because it is less dense than cold air.
Weather forecasting {meteorology}| depends on atmosphere, humidity, pressure, and wind photographs and measurements.
A halo {sun dog}| around Sun or Moon after fine weather forecasts rain.
Weather maps {weather map} {map, weather} can show isotherms and isobars.
Equal-pressure points {isobar} can be on weather maps.
Equal-temperature points {isotherm} can be on weather maps.
Temperature differences cause air movement {wind}|. Hot air rises, and cool air falls.
mountains
Wind goes up mountains by day, because top heats first, and goes down by night, because top cools first.
land and sea
During day, wind goes from sea to land, as land heats first and air rises from it. At night, wind goes from land to sea, because water's high heat capacity causes sea to stay warmer longer.
ocean
Jet streams and polar winds make oceans flow clockwise in Northern Hemisphere and counterclockwise in Southern Hemisphere, making west coasts dry near equator and wet near pole, and east coasts humid, with big storms.
Earth rotation
Warm air at equator rises and flows toward poles under tropopause. Cold air at poles stays near ground and moves toward equator. Earth rotation makes air at surface flow from east to west in Arctic and east to west in equatorial zone.
Equatorial hot air rises and flows north as cold air from north slides under it, while spinning Earth spins these masses clockwise in Northern Hemisphere and counterclockwise in Southern Hemisphere. Middle, temperate latitudes have no steady surface winds but usually two or three great swirls, with eddies.
Tropical-cyclone wind speed has score 0 to 12 {Beaufort scale}|, or 0 to 17, for 0 to 200 miles per hour.
High-pressure swirls {cell, air}| are more near poles and in subtropics. Low-pressure cells are more in temperate zones.
Earth rotation causes {Coriolis force} air-spin direction.
Tropical-cyclone centers {eye, storm}| are calm and several kilometers wide.
Cold-air mass and warm-air mass can contact {front, air}| when air masses start to move. Polar easterlies can meet southern westerlies {polar front}. At fronts, warm air rises and cools to make clouds and precipitation.
Cold air can replace warm air {cold front}|, or cold-air masses can move into regions. Cold fronts bring rolling dark clouds and lightning, moving fast and steep, as cold air tunnels under warm air, with hard rain. Cold fronts first make cumulonimbus clouds and later make dark low clouds and small strong storms. Cold fronts can make squall lines, from which can come tornados.
Warm air masses can move into regions {warm front}|. Warm fronts first bring high clouds, because warm air goes over cold-air top, and then low clouds, moving slow and long with steady rain. Warm fronts first make cirrus clouds, then cirrostratus clouds, then altostratus clouds, and then nimbostratus clouds, with broad light rain.
Objects can be downwind {leeward}|.
Objects can be upwind {windward}|.
Winds go clockwise around high-pressure region near Azores. Winds {Arctic Oscillation} (AO) go counterclockwise around low-pressure region near Iceland. If low pressure is very low, north Europe, north Asia, and Alaska receive warm wind, and Greenland, east Canada, and south Europe receive cold wind.
Yugoslavia mountains make cold air {bora} that flows to Adriatic Sea.
Warm winds {brickfielder} can be in Australia.
Squalls {bull's eye squall} can be at Cape of Good Hope.
Strong winds {buran} can be in Russia.
Warm day winds {chinook}| can come down east Rocky Mountains, because that side receives no sunlight and is cool.
Warm air surrounded by cold air rises and spins counterclockwise {cyclone}| in Northern Hemisphere or clockwise in Southern Hemisphere. Earth rotation causes spin direction. Warm air can hold more water than cold air. As warm moist air rises, it cools and condenses water, causing precipitation.
anticyclone
If surrounded by warm air, cold air falls and spins clockwise {anticyclone} in Northern Hemisphere or counterclockwise in Southern Hemisphere. Cold air is drier, so as it rises, it causes clear skies.
density
In Northern Hemisphere, warm air goes north to cooler regions and rises, because it is less dense, and cool air goes south to warmer regions and falls, because it is more dense. Moving air masses can cause air to swirl counterclockwise or clockwise. Cyclone makes warmer, wetter air rise, causing low pressure and wet days. Anti-cyclones make colder, dryer air fall, causing high pressure and dry days.
West winds {datoo} can be in Gibraltar.
Just north or south of equator {doldrums}|, winds are weak.
Cool Greek winds {etesian} can blow in summer.
Warm day winds {foehm} can come down north Alps, because that side receives no sunlight and is cool.
strong Swedish wind {frisk vind}.
From 25 to 30 degrees south latitude or north latitude {horse latitudes}|, winds are small.
Temperate-zone high-altitude winds {jet stream}| flow east at lower latitudes and west at higher latitudes.
Japan has gentle breezes {matsukaze} in pines.
Rhone-River-valley glacier makes cold air {mistral}| that flows to Mediterranean Sea.
Winds go clockwise around high-pressure region near Azores. Winds {North Atlantic Oscillation} (NAO) go counterclockwise around low-pressure region near Iceland. If low pressure is very low, north Europe, north Asia, and Alaska receive warm wind, and Greenland, east Canada, and south Europe receive cold wind.
Hot dry summer winds {Santa Ana}| can be in California.
Sahara Desert heats wind {sirocco}|, which picks up water from Mediterranean Sea and rains on Italy.
Winds {solano} can be in Spain.
Equator east-to-west winds {trade wind}| are steady at low altitude.
Japan has strong winds {tsumuji}.
Winds {vento coado} can flow on Portuguese hills.
Humid winds {waimea} are in Hawaii.
Winds {williwaw} can blow in Alaska.
gentle warm wind {zephyr}|.
Hot dry winds {zonda} from Andes Mountains can blow across Argentina pampas.
Winds {gale}| can blow from 51 to 102 kilometers per hour.
Desert sandstorms have high humidity, low temperature, and 45-mph winds {haboob}, such as along Nile River.
In Caribbean Sea, cool air can surround warm moist air that rises faster, spinning into tropical cyclones {hurricane}| with winds up to 200 mph. About 48 hurricanes and typhoons happen a year, usually in late summer.
In Southeast Asia, warm land and cool sea causes summer storms {monsoon}|, but October to April is cool and dry.
In northeast USA, northeastern winds {northeaster}| can bring storms.
Sandy hot strong winds {simoom}| can be in Sahara and Arabian deserts.
Cool winds {squall}| can come suddenly and finish soon, typically with rain or snow.
Strong cold fronts can cause funnel-shaped clouds {tornado}| {whirlwind}, 300 to 600 feet diameter, with 200 mile per hour winds. Tornadoes move 25 miles per hour and travel up to 100 miles. Tornadoes are mostly in central USA and in Australia. 1500 tornadoes happen each year.
Pacific Ocean and Indian Ocean have tropical cyclones {typhoon}|. About 48 hurricanes and typhoons happen a year, usually in late summer.
Squall lines can make sea tornados {waterspout}|.
Land includes erosion and landforms {landforms}.
Rocks can move, break down, and wear away {gradational process} {erosion}|. Moving glaciers, flowing water, freezing, and thawing can cause erosion. Ocean waves cause erosion. Water movements and chemical reactions cause most erosion. Erosion is faster if water flows faster or contains more chemicals that react with minerals. Erosion also involves plants and plant roots. Sand blown by wind does little eroding.
shore
Ocean erodes centimeters from rocky shores {shore} each year. On deep and steep shores, ocean-wave erosion makes cliffs. On shallow gently sloping shores, ocean-wave erosion builds sandy beaches or sandbars.
Water can carve rock channels {fluvial landform}|.
Water can flow under surface {sapping} and cause ground erosion.
Large ice masses {glacier}| move 1 to 40 feet per day.
Glacier can have large deep crack {crevasse}|.
If glaciers reach sea, parts {iceberg}| can break off.
Ice-Age glaciers were one mile thick. When they receded and dried, wind blew fine dust {loess}| all over world.
Glacier front edge pushes up soil and rock ridge {moraine}|.
Glaciers can have vertical holes {moulin, hole}, caused by flowing water.
Slope, material, and size determine land types {terrain}| {land forms}.
slope
Varying slope makes plain, hill, or mountain.
material
Surface material can be soil, bedrock, sand, cobblestone, boulders, ice, or water.
types
Surface can be piedmont rolling plains, caused by running water, glacial erosion, or wind sand-dune formation. Surface can be hilly plains, caused by minor tectonic processes or tableland erosion. Surface can be plains, from running-water sediment deposits. Surface can be tableland, mesa, butte, canyon, or escarpment. Surface can be low mountains, from long erosion. Surface can be high mountains, formed recently.
layers
Limestone layers were shallow sea. Coal layers were swamp. Salt or gypsum indicates sea dried instead of receding.
ore layer {lode}|.
mineral-deposit area {prospect, land}|.
Rocks {talus, cliff} can be at cliff base.
vertical rock point {aiguille}.
mountain {alp}|.
plant-less eroded mesas or hills {badlands}|.
cliff top {bluff}|.
small mesa {butte}|.
crest or ridge {chine}.
pass or gap {col}.
A mountain chain {Cordilleran belt} goes from Atlas Mountains, to Alps, to Himalayas, to Pacific-Ocean volcanic islands, to north China, to east Siberia, to west North-America coast, and then to west South-America coast.
rocky promontory {crag}|.
hill top {crest, hill}|.
above-plain inclined rock strata {cuesta}.
watershed {divide}|.
hill {eminence}|.
mesa side {escarpment}|.
Two large watersheds have boundary {great divide}.
small hill {hillock}|.
knoll or mound {hummock}|.
small hill {knoll}|.
mountain {massif}|.
tableland tops {mesa}| {upland}.
river cliffs {palisade, cliff}|.
Rolling plains {piedmont}| form by running water, glacial erosion, or wind sand-dune formation.
high flatland {plateau, land}|.
sea or lake highland projection {promontory}|.
cliff {scarp}.
un-eroded mountain range {sierra}.
Plains cut by streams make mesa, butte, canyon, and escarpment {tableland}|.
Trees do not grow above a mountain line {timberline}| {timber line}.
Hilltops {tor} can have rocks or be bare rock.
deep crevice {abyss}|.
usually dry stream gully {arroyo}|.
mesa spaces {canyon}|.
gorge or crevice {chasm}|.
glaciated-valley heads {cirque}.
gulch or ravine {coulee}.
fissure {crevice}|.
valley {dale}|.
small valley {dell}|.
dry region {dust bowl}.
long narrow crack {fissure}|.
valley {glen}|.
river-caused deep narrow area {gorge}|.
stream channel {gully}|.
low and wet region {morass}|.
water-made deep narrow area {ravine}|.
muddy area {slough}|.
Glaciers can form small mountain lakes {tarn}.
Lower shore {tideland}| is under water at high tide.
low coastal land {tidewater}|.
valley {vale}|.
dried riverbed {wadi}.
plain {champaign}.
un-forested rolling plain {wold}.
Sand dunes {brachan} can be separated sand crescents.
Sand dunes {seif}| can be parallel to wind.
island group {archipelago}|.
Land {cape, land}| can project into sea.
Land {headland}| can extend into water.
Narrow land {isthmus}| can be between two oceans.
Large land {peninsula}| can project into sea.
Coral rings {reef}| {atoll} can form around volcanic islands.
Sandy areas {sandbar}| can be near shore.
sandbar {shoal}|.
shore {strand, shore}|.
tree-shaded area {arbor}|.
tree-shaded area {bower}|.
shrub and thicket area {chaparral}|.
treeless field {clearing}|.
forest open area {glade}|.
heather-covered land {heath, land}|.
Rolling plains {moor}| can have shrubs and no forests.
Desert planted areas {oasis}| have water.
Areas {verdure, area}| can have healthy green plants.
grapevine field {vineyard}.
rabbit land {warren}|.
South-America treeless grassy plain {pampas}|.
Grassy soil {sod, soil}| can have intertwined roots.
small grassy area {tuffet}| {tuft}.
small grassy area {tussock}|.
South Africa has flat grassy areas {veldt}|, where animals graze.
Firs and spruces {taiga} cover north Eurasia south of tundra.
woodland or hilly land {weald}.
Hedges or tree rows {windbreak} can be on windward side.
rock or snow slide {avalanche}|.
Regolith can move slowly {creep}.
Loose regolith can break away {landslide}| from valley wall.
Rivers and streams transport eroded, decomposed, and disintegrated rock {regolith}.
Soils {soil, land} have types and properties {pedology}|. Soil comes from eroded rocks and decayed organic matter. Soil {mountain soil} derived from lava is rich in minerals. Iron oxides cause red, yellow, or brown soil color. Humus causes black or dark-brown soil color. Soil can be acid or alkaline. Soil has layers.
Soil can have varying calcium, sodium, potassium, phosphorus, nitrogen, iron, magnesium, and sulfur amounts {soil fertility} {fertility, soil}|.
Clay and shell mixtures {marl}| can be fertilizers.
Soil types {soil texture} depend on soil particle size {peds}|. Gravel has largest peds and coarse texture. Sand is next largest. Silt is third largest. Clay has smallest peds and fine texture.
Soil can have no soil profile {azonal soil profile}.
Soil can have unstable but layered soil profile {intrazonal soil profile}.
Soil can have stable soil profile {zonal soil profile}.
Hardened soil layers {pan layer} can be below topsoil.
Soil surface layers {topsoil} can be porous and 0 to 24 inches thick.
Sediment from rivers makes sandy soil {alluvial soil}|.
humus and sand {chernozem}.
decayed organic matter {humus}|.
clay, silt, and sand mixture {loam}|.
Dry soils have different types {chernozemic soil} {grunosolic soil} {decentic soil}.
Humid soils have different types {podzolic soil} {latosolic soil} {tundra soil}.
Water {water, Earth} includes ocean and fresh water. Water is 0.001% of Earth mass.
Water {fresh water} is where rainfall is plentiful or snow accumulates. People require five gallons of fresh water a day. In USA, people use 60 gallons per person per day.
Rainfall can be small for long period {drought}|.
Field can receive water from source {irrigation}|. Irrigation by dribbling has less evaporation than spraying or flooding.
enclosed water area {basin}|.
flooded or irrigated rice field {paddy}.
large flat iceberg {floe}|.
large floating ice blocks {pack ice}|, from ice field.
wetland {marsh}|.
river or lake marsh {bayou}|.
marsh {bog}|.
bog or marsh {fen}|.
In England, tides cause marshes {wash}|. Southwest USA has dry stream beds.
Streams and rivers {river, water} receive water directly from rain and indirectly from water runoff from land. Streams are usually wider than they are deep, and erosion sediments can fill them within years. Stream first erodes into valley. Then tributaries enter valley and join first stream. Then valley sides wear down to make wide valley or wear back to make deep valley.
Undertows pull sediment from rivers out to sea. River mouths have sediment triangles {delta}|. Mississippi River makes 600,000,000 tons each year. In sea, corals use minerals, or minerals precipitate out, as at Hudson-River mouth and in Baltic Sea.
circular river current {eddy}|.
shallow river area {ford}|, where people or horses can cross.
Stream can enter salt water, or stream can have sudden flow {freshet}|.
river beginning {headwaters}|.
Rivers curve many times {meander}| if banks are soft, because river cuts away outer bank, deposits soil on inner bank, and widens all curves. Rivers run straight and cut through rock if banks are hard, to make canyons.
rivulet {rill}|.
stream {rivulet}|.
Rivers {tributary}| can flow into larger river.
In stream, hard rock plate {falls}| can persist after lower rock has eroded.
waterfall series {cascade}|.
big waterfall {cataract, water}|.
Stream or river shallow parts can have rocks resistant to erosion, where water flows faster {rapids}|.
rapids {white water}|.
water {spring, water}| burbling from ground.
Warm water from Earth interior can make hot water spouts {geyser}| that erupt several times a day.
hot spring {thermal spring}|.
Warm water {warm springs}| can come from underground.
Groundwater can dissolve carbon dioxide to make carbonic acid, which can dissolve rock {cave}|.
Landscapes {karst} can have caves and sinkholes.
Carbonic acid can dissolve limestone to make holes {sinkhole}| and collapsed ground in flat areas.
In cave, dripping water can dry and precipitate carbonates, to make up-pointing structures {stalactite}|.
In cave, dripping water can dry and precipitate carbonates, to make down-pointing structures {stalagmite}|.
Distillation or freezing can remove seawater salt {desalination}|. If water has low salt, reverse osmosis, electrodialysis, or ion exchange can remove salt.
High pressure can force water through membrane that retains salts {reverse osmosis}|, making purer water come out. If water has low salt, reverse osmosis, electrodialysis, or ion exchange can remove salt.
Porous and permeable rock {aquifer}| can hold water.
Wells {artesian well}| can reach water table.
Soil and rock water {groundwater}| depends on precipitation, evaporation, rock porosity, and soil permeability.
Water-saturated-rock upper-surface level {water table}| is same as nearby lake and pond surface level.
Soil water permeability and movement {infiltration}| is most for sand, middle for loam, and least for clay.
Water infiltration is most for sand, middle for loam, and least for clay {permeability, soil}|.
Below soil, rainwater goes into rock-crystal open spaces {porosity}|, down to 100,000 feet.
Oceans {ocean} have salt water and currents.
Upwelling water can cause tropical Pacific Ocean warming {El Ni-o}|, every six years.
Downward flowing water can cause tropical Pacific Ocean cooling {La Ni-a}|.
Ocean has 0.9% salt concentration {salinity}|.
long-wave breaker {comber}|.
small bay {cove}|.
Ocean has water flows {current, ocean}|. Surface currents flow in same direction as wind. Beneath them, surface ocean currents have colder-water counter-currents flowing more slowly in opposite direction.
names
Gulf Stream flows along North-America east coast.
Labrador Current flows past Iceland to England.
Peru or Humboldt Current flows along South-America west coast.
California Current flows along North-America west coast.
Kuroshio Current flows off Japan.
Brazil Current flows along South-America east coast.
Besquela Current flows along Africa west coast.
Antarctic Circumpolar Current (ACC) circles Antarctica and keeps tropic waters out.
Ocean has surface currents {drift, ocean}|.
narrow inlet {firth}|.
open ocean {main}|.
fast outward current {rip current}|.
fast outward beach current {riptide}|.
water area {strait}| between islands, allowing passage.
whirlpool {vortex, water}|.
Intersecting currents cause swirling water {whirlpool}|.
Sea meets land {coast, ocean}.
Sea can make small coastline indentations {bay}|.
At shore, low valleys {estuary}| can fill with rising water.
narrow bay {inlet}|, or narrow area between two islands.
At shore, steep glacier valleys {fjord} can fill with rising waters.
Sea can make big coastline indentations {gulf}|.
Oblique currents and waves create beaches, sandbars, and spits on shore, and make offshore sandbars if beach has shallow slope. Quiet water {lagoon}| can be between a sandbar and shore.
Sea has a region {littoral}| between high and low tides.
Water {sound, shore} can be between island and shore.
Ocean zones {ocean floor zones} relate to light. 0 to 600 feet has sunlight. 600 to 4000 feet has twilight. 4000 to 36,000 feet is dark. Deepest trench is 36,000 feet deep.
Sea floor {abyssal plain} is 34 F and has 1000-atmosphere pressure.
Under-sea continent region {continental shelf}| is 8% of ocean and is 400 to 600 feet deep.
Continental shelf goes down to sea floor {continental slope}.
Moon and Sun gravitation moves Earth sea and land {tide}|. Earth gravity and land-and-sea elasticity oppose tides. Shallow-water tide motion makes heat by friction, which takes energy from Earth rotational energy. Earth rotation slows, making each day slightly longer. Earth-Moon distance increases slightly each day.
When Moon is overhead or on opposite side of Earth, continents rise up to six inches and oceans rise several feet {high tide}.
When Moon is to right or left, continents and oceans are at low height {low tide} {slack tide}.
When Moon is overhead or on opposite side of Earth and Sun is to right or left, high tides {neap tide}| are lower, at first-quarter or third-quarter moon.
When Moon and Sun are both overhead or opposite sides of Earth, tide {spring tide}| is extra high, at new or full moon.
Difference {tidal range} between high and low tide is 2 feet in sheltered bays, 5 to 10 feet on open coast, and 30 to 50 feet in V-shaped bays. Tidal currents flow 5 to 10 miles per hour.
Winds cause waves {wave, ocean}|. Wave height and distance increase with wind speed, wind duration, and distance wave has traveled.
Sea bottom near shore slows wave bottom, and top wave part becomes narrow and falls over {breaker}|, where water level becomes less than wave height.
Small swells can superimpose to make big wave {tidal wave}|.
Wave water flows back to ocean along bottom {undertow}|.
Strong winds cause open-water waves {whitecap}| to break.
Rocks {mineral} have definite chemical composition. People know properties of 2000 minerals. Main elements in rocks are oxygen 48%, silicon 28%, aluminum 8%, iron 5%, sodium, magnesium, sulfur, and calcium. Together, they are 98% of crust.
types
Elements make pure minerals, like gold and copper. Sulfides, selenides, tellurides, arsenides, antimonides, and bismuthides are similar. Halides are similar. Oxides and hydroxides are similar. Carbonates, borates, and nitrates are similar, but borates and nitrates are rare. Sulfates, tellurates, chromates, molybdates, and tungstates are similar. Phosphates, arsenates, and vanadates are similar. Silicates are similar and include nesosilicates, sorosilicates, cyclosilicates, inosilicates, phyllosilicates, and tektosilicates.
color
Rocks have color and color under fluorescence.
crystal form
Most rocks are crystals {crystal form}, such as cubic crystal, with definite geometry.
density
Rocks have definite specific gravity, depending on composition and crystal structure.
homogeneous mineral
Most minerals {homogeneous mineral} are the same throughout, but bauxite, sand, granite, and porphyry are not homogeneous.
melting
Most rocks have exact melting points, but glasses, resins, and colloids have melting-point ranges.
particle size
Minerals have particle sizes. Clay has fine, cohesive particles. Silt has cohesive particles. Sand has grains. Gravel has small rocks.
refraction
Rocks have definite refractive index.
Materials can emit trapped gases over time {outgas}|.
Crystal form determines flat-surface shape {fracture plane} that appears after breaking rock.
Rocks, such as diamond, can be shiny and lustrous {luster}|. Metals, such as silver, can be lustrous, because dielectric constant is negative.
Some rocks split light into two colors {pleochroism}.
Rocks have relative strength {hardness}|, depending on chemical-bonding patterns.
Hardness scale {Moh's scale} {Moh scale} goes from 1 to 10. Diamond is 10. Cubic boron nitride is 9.5. Corundum is 9. Quartz is 7. Glass is 6. Steel is 5. Fluorite is 4. Calcite is 3. Salt is 2. Talc is 1.
Rocks can have biconvex-lens shapes {lenticular}.
Rocks can be concentric with radial arms {rosette}.
Rocks {sphenoid rock} can have wedge shapes.
Rocks can be needle-like {acicular}.
Rocks can be chalky {calcareous}.
Rocks can have powdery surface crust {efflorescence, rock}.
Rocks can have surface film {patina}|.
Rocks, such as obsidian, can be glass-like {vitreous, rock}|.
Rocks can have built-up masses {concretion}| around them.
Rocks {druse}| can have crystal linings.
Rocks {lacustrine mineral} can form in lakes.
Pure silicon can form very low-density gel {aerogel}.
Minerals {basic mineral} can have low silica content.
Compounds with group VII elements {halide mineral} have low hardness, low density, and vitreous luster. NaCl {halite} has sodium and chloride. KCl {sylvite} has potassium and chloride. CaF2 [2 is subscript] {fluorite} has calcium and fluoride.
Most elements {metal, mineral} are shiny, hard, electric-charge conducting, and heat conducting.
Aluminum comes from aluminum oxide in bauxite.
Calcium is from limestone.
Gold is pure in Latin America, California, Australia, Alaska, and South Africa.
Iron is from iron oxides.
Manganese comes from ocean-floor nodules.
Mercury comes from cinnabar.
Coking coal or freezing air frees nitrogen.
Phosphorus comes from calcium phosphates in limestone deposits.
Potassium comes from many rock types. Potassium-40 is radioactive.
Sulfur is half as free sulfur and half as metal sulfides, in Gulf of Mexico, Italy, Japan, and Russia.
Tin comes from cassiterite.
Scheelite is tungsten ore.
Uranium is in Congo, Romania, Canada, and Colorado.
Zinc comes from zinc oxides.
Compounds {phosphate mineral} with phosphorus and oxygen are secondary minerals and have color. Phosphates include apatite, turquoise, and autunite.
Unlike most substances, some crystals {Rochelle salt} become less symmetrical and more ordered at high temperature.
Carbon-oxygen compounds {carbonate mineral} can have medium or low hardness, be white or highly colored, and effervesce if dissolved in hydrochloric acid. Calcite has calcium and is the most-common mineral, as chalk and limestone. Dolomite has calcium and magnesium and is second most-common mineral. Carbonates include siderite, magnesite, cerussite, azurite, malachite, soda, and borax.
Na2CO3 [2 and 3 are subscripts] {soda}| has sodium and is hydrous.
Compounds {oxide mineral} with oxygen vary. Oxides include bauxite, spinel, magnetite, chromite, corundum, cuprite, zincite, hematite, rutile, cassiterite, and uraninite.
BaSO4 [4 is subscript] {barite} is main barium ore.
SnO2 [2 is subscript] {cassiterite} is main tin ore.
TiO2 [2 is subscript] {rutile} has titanium and is semiconductor. It can catalyze water to oxygen and hydrogen under ultraviolet light {photolysis}, and organic molecules to carbon dioxide and water under ultraviolet light, by making superoxide and hydroxyl radicals. Titania thin films make things wettable {wettability} and so self-cleaning.
Aluminum or iron oxides can form rocks {spinel} that have no cleavage.
UO2 [2 is subscript] {uraninite} has uranium.
Manganese oxide can be in hydrous ore {wad}.
Compounds {sulfate mineral} with sulfur and oxygen have low hardness, have vitreous luster, and are not opaque. Sulfates include anhydrite, gypsum, selenite, alabaster, barite, and jarosite.
Hydrous NaAlSO4, KAlSO4, and NH4AlSO4 [4 is subscript] {alum} are aluminum sulfates with sodium, potassium, and ammonia. Alum treats canker sores and is for water purification. Aluminum potassium sulfate is AlK(SO4)2 [4 and 2 are subscripts].
Hydrous sulfates {vitriol} are secondary minerals formed in ore and can be green or blue-green {iron vitriol}, white {zinc vitriol}, pale green {nickel vitriol}, or blue {copper vitriol}.
Compounds {sulfide mineral} with sulfur have metallic luster. Sulfides include pyrite, chalcopyrite, galena, cinnabar, molybdenite, argentite, and marmatite.
Ag2S [2 is subscript] {argentite} has silver.
HgS {cinnabar}| is the most-important mercury ore.
MoS2 [2 is subscript] {molybdenite} is the most-common molybdenum mineral.
Sb2S [2 is subscript] {stibnite} has antimony.
Aluminum-oxide, iron-hydroxide, and silicate mixture {bauxite}| is main aluminum ore and is mainly in Yugoslavia, France, Italy, and Guyana.
BeAl2O4 [2 and 4 are subscripts] {chrysoberyl} {alexandrite} has beryllium and aluminum and makes violet gems and cat's eyes.
Al2O3 [2 and 3 are subscripts] {corundum} {emery} has aluminum.
Corundum can be red transparent jewels {ruby, mineral}|.
Corundum can be blue jewels {sapphire}|.
Na2BO3 hydrous [2 and 3 are subscripts] {borax}| is colorless, translucent, and hydrous.
Calcium and boron carbonate fibers {ulexite} {television stone} let light travel through their fibers.
CaSO4 [4 is subscript] {anhydrite} has calcium.
Ca3F(PO4)3 [3 and 4 are subscripts] {apatite} has calcium and iron and is yellow-green.
Ca(UO2)2(PO4)2 . 12 H2O [2 and 4 are subscripts] {autunite} has calcium and uranium oxide and is hydrous.
CaMg(CO3)2 [3 and 2 are subscripts] {dolomite}| has calcium and magnesium and is second most-common mineral.
CaWO4 [4 is subscript] {scheelite} is tungsten ore.
CaCO3 [3 is subscript] {calcite} has calcium and is the most-common mineral, as chalk and limestone.
Calcite {limestone}| is the most-common mineral.
CaSO4 . 2 H2O [4 and 2 are subscripts] {gypsum}| has calcium and is hydrous, colorless, laminar, and light. It can be selenite and alabaster.
Gypsum can be layered, compacted, and colored {alabaster, mineral}.
Gypsum can be individual crystals {selenite}.
Starting 345,000,000 years ago, swamps formed and sea sediments covered them hundreds of times, making many rock and dead-plant layers. Layer weight created high pressure that changed organic matter into carbon forms {carbon mineral}.
types
Under pressure, organic matter turns slowly into first peat, then lignite, then bituminous coal, and then anthracite coal, as it becomes more crystalline.
coal
Many places that used to be under sea have coal, such as USA, Canada, England, and Russia.
petroleum
Decaying organic matter trapped in anti-clinal deposits became petroleum, with natural gas above it, as in Saudi Arabia, Middle East, and Russia.
diamond
Diamonds are covalently bound pure carbon and form at 5000 F and 1,000,000 lb/in^2 pressure, 240 miles below surface. Almost all diamonds are in South Africa. Diamond size is by weight {carat}.
graphite
Graphite is soft carbon. Hexagon graphite layers include heptagons, resulting in negative curvature. Hexagon graphite layers include pentagons, resulting in positive curvature.
Pure carbon can be amorphous {amorphous carbon}, with diamond bonds and graphite bonds.
Pure carbon can form into balls {buckyball} {buckminsterfullerene} with five-carbon and six-carbon rings, like soccer ball hexagons and pentagons.
Pure carbon can form low-density gel {carbon aerogel}.
Yams, soybeans, and tropical plants have lower carbon-13 to carbon-12 ratio than temperate-zone plants {carbon isotope ratio test} (CIR).
Pure graphite hit by meteorites forms hexagonal structure {chaoite}.
Pure carbon fibers can have small plates in chains {filamentous carbon}.
Pure carbon {graphene} can form plane hexagonal arrays. Array is flexible but stronger than diamond. Graphene has strong bonds and flexibility and so rarely has missing atoms or impurities. Graphene conducts electricity fastest, because bonds are strong and crystal defects are few. Charge carriers move at 1/300 light speed and have relativistic effects.
Pure carbon can form hexagonal-pattern diamonds {lonsdaleite} {hexagonal diamond}.
Pure carbon can form aerogel-like structure {nanofoam} that is ferromagnetic.
Pure carbon can make material {nanorod} harder than diamond.
Pure carbon can form into six-carbon-ring tubes {buckytube} {nanotube, carbon}, 10 or more carbons diameter, 10000 carbons long, strong, heat-resistant, radiation-resistant, resilient, flexible, conducting or semiconducting, and nested or single (Sumio Iijima) [1991]. Random nanotubes arrangements {nanonet} conduct electricity.
Pure carbon can form hexagonal structure {schwartzite} with included heptagons.
Cu3(CO3)2(OH)2 [3 and 2 are subscripts] {azurite} is blue copper ore and is hydrous.
Cu2S [2 is subscript] {calcocite} has copper.
CuFeS2 [2 is subscript] {chalcopyrite} is the most-common copper ore.
Cu2O [2 is subscript] {cuprite} has copper.
Cu2CO3(OH)2 [2 and 3 are subscripts] {malachite} has copper, is green, and is hydrous.
CuAl6(PO4)4(OH)8 . 5 H2O [6, 4, 8, and 2 are subscripts] {turquoise, mineral}| has copper, is hydrous, and is sky blue. It is in Iran, Siberia, Turkestan, New Mexico, and Arizona.
FeCr2O4 [2 and 4 are subscripts] {chromite} has iron and chromium and can be spinel {ruby spinel} {balas ruby}.
Fe2O3 [2 and 3 are subscripts] {hematite} {oligist} is iron ore.
KFe3(SO4)2(OH)6 or NaFe3(SO4)2(OH)6 or AgFe3(SO4)2(OH)6 or PbFe3(SO4)2(OH)6 [3, 4, 2, 6, and 3 are subscripts] {jarosite} are iron sulfates with potassium, sodium, silver, or lead.
Iron oxides can be hydrous ores {limonite}.
Fe3O4 [3 and 4 are subscripts] {magnetite} has iron and is spinel.
ZnFeS2 [2 is subscript] {marmatite} has zinc and iron.
FeS2 [2 is subscript] {pyrite}| {fool's gold} has iron and is the most-common sulfide.
FeCO3 [3 is subscript] {siderite} is minor iron ore.
PbCO3 [3 is subscript] {cerussite} is lead ore.
PbS {galena} has lead and often associates with silver.
MgSO4 . 7 H2O [4, 7, and 2 are subscripts] {epsonite} {Epsom salt}| has magnesium, is hydrous, forms by evaporation, and is white.
MgCO3 [3 is subscript] {magnesite} has magnesium.
ZnS {sphalerite} {zincblende} {schalenblende} has zinc.
ZnO {zincite} has zinc.
Rocks are inorganic, but living things make resin, bitumen, and amber {organic mineral}.
Living things make minerals {amber, mineral}.
Dead living things can form minerals {bitumen}|.
Rocks {lagerstätten} can retain traces of soft-bodied animals and animal burrows. Solnhofen Limestone in Germany has fossil Archaeopteryx. Burgess Shale in British Columbia, Canada, has Cambrian fossils. Chienjiang in Yunnan Province, China, has early Cambrian fossils. Doushantuo Formation in Guizhou Province, China, has early Precambrian fossils in calcium phosphate. Ediacara Hills in Australia have Precambrian fossils.
pearl-oyster inside shell {nacre} {mother-of-pearl}|.
pearl-oyster round excretion {pearl, gem}|.
Plants make minerals {resin, mineral}|.
Silicon and oxygen compounds {silicate mineral} are hard and are 1/3 of all minerals. SiO2 [2 is subscript] is triangular. Silicon dioxide is in granite and obsidian. It forms at 600 C to 900 C. It has density 2.7 g/cm^3. SiO4 [4 is subscript] is tetrahedral. Silicon oxides can have another form {tridimyte}. Silicates can be nesosilicate, sorosilicate, cyclosilicate, inosilicate, phyllosilicate, or tektosilicate.
Silicon oxides {silica}| can be grains.
hardness-7 gray silicate {flint}.
Calcium silicate, magnesium silicate, and iron silicate {gabbro} can be together.
Hard glass {rhinestone}| has many colors and is for jewels.
Tetrahedral silicates {sorosilicate} can have two tetrahedra. Zn4Si2O7(OH)2 . H2O [4, 2, and 7 are subscripts] {hemimorphite} {calamine} is sorosilicate, is secondary zinc mineral, and is milk white or blue.
SiO2 . n H2O [2 is subscript] {opal}| is colloidal and can have iridescence {precious opal}, red reflections {fire opal}, or be in trees {wood opal}.
Opal can have glassy appearance {hyalite} in granite.
SiO2 [2 is subscript] {quartz}| has crystals and is glassy or milky {rock crystal}, brown {smoky quartz}, black {morion quartz}, citrine, pink {rose quartz}, amethyst, chalcedony, agate, onyx, or jasper.
Quartz {agate}| can have different color bands.
Quartz {amethyst}| can be violet.
Quartz {chalcedony} can have translucent microcrystals.
Quartz {citrine} can be yellow.
Quartz {jasper} can be many-colored.
Quartz {onyx}| can have straight black-and-white bands.
Tetrahedral silicates {cyclosilicate} can be rings.
CuSiO2(OH)2 [2 is subscript] {dioptase} is copper cyclosilicate and is green.
Be3Al2Si6O18 [3, 2, 6, and 18 are subscripts] {beryl}| is aluminum cyclosilicate and can be hexagonal beryllium ore {pegmatite}, emerald, or aquamarine.
Beryl can be blue minerals {aquamarine, mineral}.
Beryl can be green minerals {emerald}|.
(Na,Ca)(Li,Mg,Fe,Al)3(Al,Fe)6B3Si6O27(O,OH,F)4 [3, 6, and 27 are subscripts] {tourmaline}| is aluminum and iron cyclosilicate and commonly is schorl.
Tourmaline commonly is a black mineral {schorl}.
Triangular silicates {inosilicate} can be long chains.
Inosilicate {pyroxene} can be green or black and granular or fibrous.
CaMgSi2O6 [2 and 6 are subscripts] {diopside} is calcium and magnesium pyroxene.
feldspar and pyroxene mixture {basalt}|.
Inosilicate {amphibole} can be white to black-green.
Hard green amphibole {jade}| is for jewelry.
(Ca,Na,K,Mg,Fe,Al)Si2O6 [2 and 6 are subscripts] {hornblende} is calcium, sodium, potassium, magnesium, iron, and aluminum amphibole and is monoclinic.
Silicates {nesosilicate} can be isolated tetrahedra.
(Mg,Fe)2SiO4 [2 and 4 are subscripts] {olivine}| {chrysolite} {peridotite} is magnesium and iron nesosilicate and is green to yellow-brown. Peridotite igneous rock in mantle can react with seawater to make hydrogen. Hydrogen reacts with carbon-containing molecules to make methane.
CaTiSiO5 [5 is subscript] {titanite} is titanium nesosilicate.
Al2SiO4(OH,F)2 [2 and 4 are subscripts] {topaz, mineral}| is aluminum nesosilicate and can be yellow, amber, or blue. Transparent form {chiastolite} is in Spain.
Fe3Al2(SiO4)3 [3, 2, and 4 are subscripts] {almandine, mineral} is aluminum nesosilicate.
Almandine can be isometric, red, and translucent {garnet}|.
Zr(SiO4) [4 is subscript] {zircon, mineral}| is zirconium nesosilicate and can be orange or red {hyacinth, zircon}.
Zircon can be prismatic {adamantine}.
Triangular silicates {phyllosilicate} can have flat layers.
K2(Mg,Fe,Al)4-6(Si,Al)8O20(OH)4 [2, 4, 6, 8, and 20 are subscripts] {biotite} {black mica} is phyllosilicate and is lustrous and lamellar.
Chlorine-containing phyllosilicates {chlorite} are lamellar and dark green or blue-green.
KAl3Si3O10(OH)2 [3 and 10 are subscripts] {white mica} {mica}| is phyllosilicate and is pearly and lamellar. Aluminum silicates form at 900 C to 1400 C. They have density 2.6 g/cm^3 to 3.5 g/cm^3. Aluminum-silicate compounds include feldspar, hornblende, and biotite. Aluminum silicates with minerals are clays.
Mg3Si2O5(OH)4 [3, 2, 5, and 4 are subscripts] {serpentine, mineral}|, from Alps and Apennines, is phyllosilicate and can be chrysolite, asbestos serpentine, and antigonite.
Mg3Si4O10(OH)2 [3, 4, and 10 are subscripts] {talc}| is phyllosilicate and is white or gray, greasy, and monoclinic.
Talc can form stone {soapstone}|.
Triangular silicates {tektosilicate}, such as feldspar, can be three-dimensional structures. Tektosilicates are the most-common silicates.
feldspar and plagioclase mixture {andesite}.
CaAl2Si2O8 [2 and 8 are subscripts] {anorthite} is tektosilicate.
CaB2Si2O8 [2 and 8 are subscripts] {lazurite} {lapis lazuli}| is tektosilicate, is blue or dark blue, and is granular.
KAlSi3O8 [3 and 8 are subscripts] {orthoclase} is tektosilicate and is monoclinic.
NaAlSi3O8 [3 and 8 are subscripts] {plagioclase} is tektosilicate.
NaCa2Al5Si13O36 . 14 H2O [2, 5, 13, and 36 are subscripts] {stillbite} is tektosilicate and can be zeolite.
Stillbite can be aluminum silicate {zeolite} that swells under heat.
Triangular silicates {feldspathoid} {feldspar}| can be low in silicon. Feldspar is the most-common silicate.
Feldspar {moonstone}| can have pearl luster.
Fine-grained igneous rock has large feldspar crystals {porphyry}.
Rocks {rock, types} can be igneous, metamorphic, or sedimentary.
Molten minerals from mantle cool and harden at different rates to make rock {igneous rock}|.
Igneous-rock slow cooling makes coarse grain crystals {granite}|.
dark, hard, smooth {diorite}.
Igneous-rock rapid cooling makes fine grain crystals {obsidian}.
Rhyolite {pumice} can form with gas bubbles.
Fine-grained glassy granite {rhyolite} has color bands.
Basalt lava flows have red-brown, porous rocks {scoria} that contain gas bubbles.
Igneous rocks {sialic rock} can be mostly silicon and aluminum. Granite, continental rock, and sediments are sialic.
soft volcanic rock {tufa}.
aerated light volcanic rock {tuff}.
Sand or clay layers can make rock {sedimentary rock}|. Water, wind, or ice makes sand or clay layers. Layers can be clastic rock, crystallize from shallow lakes or seas by evaporation to make sediment, or precipitate to make sediment. Sedimentary rocks can be calcite limestone and calcium-and-magnesium carbonate dolomite. Sedimentary rocks are the only rocks that have no reheating, so they can retain fossil imprints.
Layers can cement together by pressure {clastic rock}.
Sedimentary rocks {conglomerate rock} can come from stones and gravel in hardened clay.
Sedimentary rocks {sandstone}| can come from sand.
Sedimentary rocks {shale}| can come from clay and wood.
Igneous or sedimentary rocks can change to new forms {metamorphic rock}| by heat and pressure deep in Earth.
Metamorphic rocks {breccia} can come from conglomerate.
Metamorphic rocks {diabase} can come from basalt.
Metamorphic rocks {gneiss} can come from granite.
Metamorphic rocks {marble}| can come from limestone or dolomite.
Metamorphic rocks {quartzite} can come from sandstone.
Metamorphic rocks {schist}| can come from shale and basalt.
Metamorphic rocks {slate, rock}| can come from clay or shale.
He lived 1887 to 1966 and studied gravity. Strong negative isostatic anomalies {Meinesz belts} parallel deep-sea trenches [1921 to 1937]. Downbuckling results from compression between large, rigid crustal blocks.
He lived 1893 to 1981 and studied life's origin [1952] and ocean temperature variation [1931].
He lived 1877 to 1962 and went 1000 meters below sea level in bathysphere [1934].
He lived 1914 to 1997 and started cloud seeding [1946] with silver iodide for more rain {cloud seeding}.
He lived 1797 to 1875. Wind, water, pressure, and heat forces can make mountains, riverbeds, coastlines, and other land shapes. Events observed in present explain events in past. World always has same laws {uniformitarianism}.
He lived 1857 to 1936, studied seisomology, and discovered [1909] discontinuity at crust and mantle {Mohorovicic Discontinuity, Mohorovicic}.
He lived 1890 to 1965, did first radiometric rock dating [1911], and championed continental drift and plate spreading.
He lived 1880 to 1930 and developed continental-drift theory [1912 to 1928].
He lived 1879 to 1958. Earth-axis variation and atmospheric insulation caused ice ages [1925].
He lived 1906 to 1969. Mantle convection caused continental drift and sea-floor spreading [1957].
He lived 1924 to 1977 and mapped ocean floor [1958].
He lived 1914 to 2006 and found radiation belts around Earth [1958].
Vine lived 1939 to ?. Matthews lived 1931 to 1997. They studied magnetic pole flipping compared to seafloor spreading [1963].
He studied sea floor spreading and earthquakes, with Jack Oliver and Bryan L. Isacks, and said that plates float [1968].
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Date Modified: 2022.0225