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FROST
Forthecompleteencyclopedicentrywithmediaresources,visit:
http://www.nationalgeographic.org/encyclopedia/frost/
Frostiswatervapor,orwateringasform,thatbecomessolid.Frostusually
formsonobjectslikecars,windows,andplantsthatareoutsideinairthatis
saturated,orfilled,withmoisture.Areasthathavealotoffogoftenhaveheavy
frosts.
Frostformswhenanoutsidesurfacecoolspastthedewpoint.Thedewpointis
thepointwheretheairgetssocold,thewatervaporintheatmosphereturns
intoliquid.Thisliquidfreezes.Ifitgetscoldenough,littlebitsofice,orfrost,
form.Theiceisarrangedintheformoficecrystals.
Frostismostcommoninlow-lyingareas.Warmairrises,andcoolairsinks—
coolairisdenserthanwarmair.Thatmeansthereareusuallymorewater
moleculesincoolairthaninwarmair.Ascoolaircollectsinvalleys,frostforms.
Frostusuallyformsatnight,whentheairtemperatureiscooler.Oncethesun
risesandwarmstheairaroundthefrostedobject,frostmeltsquickly.
TypesofFrost
Therearedifferenttypesoffrost.Themostcommonareradiationfrost(also
calledhoarfrost),advectionfrost,windowfrost,andrime.
Radiationfrostisfrostintheformoftinyicecrystalsthatusuallyshowsupon
thegroundorexposedobjectsoutside.Hoarfrostalsoformsinrefrigeratorsand
freezers.
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Advectionfrostisacollectionofsmallicespikes.Advectionfrostformswhena
coldwindblowsoverthebranchesoftrees,poles,andothersurfaces.
Windowfrostformswhenaglasswindowisexposedtocoldairoutsideand
moistairinside.Windowfrostisfamiliartowinterresidentsofcoldclimates.
Indoorheatandcoldoutdoortemperaturesformthistypeoffrost.Windowfrost
wasmuchmorecommonbeforepeoplebeganusingdouble-panedwindows.
Rimeisfrostthatformsquickly,usuallyinverycold,wetclimates.Rimealso
formsinwindyweather.Rimesometimeslookslikesolidice.Shipstraveling
throughcoldplacesliketheArcticOceanoftenendupwithrimecoveringat
leastpartoftheexposedpartoftheship.
FrostandPeople
Frostcanseverelydamagecrops.Itcandestroyplantsorfruits.Plantswiththin
skins,suchastomatoes,soy,orzucchini,canberuined.Iffrostisbadenough,
potatoeswillfreezeintheground.Farmershavehadentirefieldsdestroyedin
justafewfrostynights.
Farmerstypicallyconsultalmanacsandmapstopredictfrost.Mapsand
informationfromalmanacs(suchaspreviousdaysoffrost)tellfarmerswhat
areasusuallyreceivefrost,howoftenitoccurs,andhowlongitlasts.These
toolsarereliablebutarenotalwaysaccurate.
Althoughfarmersstillrelyontheweather,manyspraytheircropstoreduce
frostdamage.Thissprayusuallycontainsageneticallymodifiedorganism
(GMO),anorganismwhosegeneshavebeenalteredbypeople.TheGMOthat
reducesfrostdamagetocropsiscalledice-minusbacteria.Ice-minusbacteria
makeitdifficultforicecrystalstoform.Ice-minusbacteriadonodamagetothe
plant.
Manyfarmersalsoprotecttheircropsbyusingtheselectiveinvertedsink(SIS)
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method.Theselectiveinvertedsinkisalargefanthatdrawscold,moistairup
intoachimney.Thechimneyexpelsthecoldairfarabovethecrops.This
protectscropsfromfrostwithoutsprayingthem.
Sturdierplantsarenotdestroyedbyfrost,butfrostwillstopthemfromgrowing.
Evergreentrees,suchaspineandspruce,willstopgrowingduringafrost,but
theywon'tdie.
Roadscanalsobedamagedbyfrost.Frostyroadsareslipperyand,exposedto
theheatfromcars,quicklybecomewet.Manydrivershavetroublenavigating
frostyorwetroads.
Vocabulary
Term
accurate
Partof
Definition
Speech
adjectiveexact.
advectionfrost noun
icecrystalsshapedlikespikesthatformfromacold
wind.
air
noun
layerofgasessurroundingEarth.
almanac
noun
Antarctic
noun
ArcticOcean
noun
climate
noun
crop
noun
delicate
adjectivefragileoreasilydamaged.
dense
havingpartsormoleculesthatarepackedclosely
adjective
together.
annualpublicationcontainingacalendar,astronomical
information,andweatherforecasts.
regionatEarth'sextremesouth,encompassedbythe
AntarcticCircle.
oneofEarth'sfouroceans,borderedbyAsia,Europe,
andNorthAmerica.
allweatherconditionsforagivenlocationovera
periodoftime.
agriculturalproduce.
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Term
Partof
Definition
Speech
temperatureatwhichwaterintheaircondensesto
dewpoint
noun
evergreen
noun
treethatdoesnotloseitsleaves.
expel
verb
toejectorforceout.
farmer
noun
personwhocultivateslandandraisescrops.
fog
noun
cloudsatgroundlevel.
freeze
noun
frost
noun
frostflower
noun
fruit
noun
formwaterdropletsonobjectsneartheground.
weatherpatternoftemperaturesbelow0degrees
Celsius(32degreesFahrenheit).
thincoatoficecoveringobjectswhenthedewpointis
belowfreezing.
icecrystalsthatformfrommoisturereleasedbya
plantstemortree.
ediblepartofaplantthatgrowsfromaflower.
stateofmatterwithnofixedshapethatwillfillany
gas
noun
containeruniformly.Gasmoleculesareinconstant,
randommotion.
gene
noun
genetically
modified
noun
organism(GMO)
partofDNAthatisthebasicunitofheredity.
livingthingwhosegenes(DNA)havebeenalteredfor
aspecificpurpose.
brittle,transparentsubstancemadefrommeltedand
glass
noun
hoarfrost
noun
ice
noun
waterinitssolidform.
icecrystal
noun
solidicearrangedinprecisemolecularform.
noun
organismthatmakesitdifficultforfrosttoform.
ice-minus
bacteria
map
noun
fusedmineralssuchassilica.
icecrystalsthatformaswatervapornearobjects
becomessolid.Alsocalledradiationfrost.
symbolicrepresentationofselectedcharacteristicsof
aplace,usuallydrawnonaflatsurface.
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Term
Partof
Definition
Speech
moisture
noun
molecule
noun
mountain
noun
pane
noun
pine
noun
typeofevergreentreewithneedle-shapedleaves.
potato
noun
plantnativetotheAmericas.
predict
verb
toknowtheoutcomeofasituationinadvance.
radiationfrost
noun
refrigerator
noun
reliable
adjectivedependableorconsistent.
rhyme
noun
rime
noun
icecrystalsthatforminwet,windyconditions.
sailor
noun
personwhoworksaboardaship.
noun
(1772-1834)Englishpoet.
SamuelTaylor
Coleridge
saturate
verb
selective
invertedsink
noun
(SIS)
wetness.
smallestphysicalunitofasubstance,consistingoftwo
ormoreatomslinkedtogether.
landmassthatformsastectonicplatesinteractwith
eachother.
sheetofglassorothermaterialplacedinaframefor
awindow.
icecrystalsthatformaswatervapornearobjects
becomessolid.Alsocalledhoarfrost.
spacewithartificiallyloweredtemperature.
wordthathasthesameendingsoundasanother
word.
tofillonesubstancewithasmuchofanother
substanceasitcantake.
methodofpreventingorreducingfrostdamageto
cropsbyfanningcold,moistairupachimney.
soy
noun
beans,orfruit,ofthesoybeanplant,nativetoAsia.
spruce
noun
coniferous,orcone-bearing,tree.
temperature
noun
degreeofhotnessorcoldnessmeasuredbya
thermometerwithanumericalscale.
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Term
Partof
Definition
Speech
tomato
noun
vapor
noun
plantandfruitnativetotheAmericas.Alsoconsidered
avegetable.
visibleliquidsuspendedintheair,suchasfog.
stateoftheatmosphere,includingtemperature,
weather
noun
atmosphericpressure,wind,humidity,precipitation,
andcloudiness.
movementofair(fromahighpressurezonetoalow
wind
noun
pressurezone)causedbytheunevenheatingofthe
Earthbythesun.
icecrystalsthatformwhenawindowisexposedto
windowfrost
noun
freezingtemperaturesononesideandmoistairon
theother.
zucchini
noun
typeofvegetable(squash).Alsocalledacourgette.
Articles&Profiles
SnowCrystals.com:GuidetoFrost
Audio&Video
NationalGeographicMusic:ChrisNormanEnsemble,IntheFieldofFrostand
Snow
Maps
NOAA:Freeze/FrostMaps
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