On food and cooking the science and lore of the kitchen ( PDFDrive ) 1494
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exertsastrongerpullontheelectrons(small
dots) it shares with the hydrogen atoms, the
water molecule is electrically unsymmetrical.
The separation of positive and negative
centers of charge leads to the formation of
weak bonds between oppositely charged
centers on different molecules. These weak
bonds between molecules, shown here by
dashedlines,arecalledhydrogenbonds.
WaterIsGoodatDissolvingotherSubstances
Waterformshydrogenbondsnotonlywith
itself,butwithothersubstancesthathaveat
leastsomeelectricalpolarity,some
unevennessinthedistributionofpositiveand
negativeelectricalcharges.Oftheothermajor
foodmolecules,whicharemuchlargerand
morecomplexthanwater,bothcarbohydrates
andproteinshavepolarregions.Water
moleculesareattractedtotheseregionsand
clusteraroundthem.Whentheydothis,they
effectivelysurroundthelargermoleculesand
separatethemfromeachother.Iftheydothis
moreorlesscompletely,sothateach
moleculeismostlysurroundedbyacloudof
watermolecules,thenthatsubstancehas
dissolvedinthewater.
WaterandHeat:FromIcetoSteam
Thehydrogenbondsamongitsmolecules
haveastrongeffectonhowwaterabsorbsand
transmitsheat.Atlowtemperatures,water
existsassolidice,itsmoleculesimmobilized
inorganizedcrystals.Asitwarmsup,itfirst
meltstobecomeliquidwater;andthenthe
liquidwaterisvaporizedtoformsteam.Each
phaseisaffectedbyhydrogenbonding.
IceDamagesCellsNormally,thesolidphase
ofagivensubstanceisdenserthantheliquid
phase.Asthemolecules’attractionforeach
otherbecomesstrongerthantheirmovements,
themoleculessettleintoacompact
