Whilelearningthesciencelessons,Iusedtogetadoubt--whyear,nose,tongueandeyesshouldbecalledasspecialsenses?Thebasicreasonisthatthesearethechannelsthroughwhichwemaintaincontactwiththesurroundings.Thoughapparentlyitmayfeelliketheseareindividualsensoryorgans,theydoshowsomeconnectivity.Interestingly,ourhearingislesssharpafterweeataheavyfood.Isn’titgoodforasoundnapafterastomach-fullmeal?Thatdoesnotmeanwegodeafafterameal,butthehearingpitch（强度）doeschangeafteraheavymeal.
Weusuallygivecreditofthetastetoourtongue,butdoyouknowthatunlesssaliva（唾液）dissolvessomething,ourtonguecannotrecognizethetasteofthefoodeaten.Tasteisnothingbutthefoodchemicalsdissolvedinthesalivabeingsensedbythetastebuds（味蕾）presentonthetongue.Trytodryoffyourtongueandmouthwithatissuepaperandthentastesomething.
Womenaremuchbettersmellersthanmen.Theyarebornwiththischaracteristicabilityandcancorrectlyrecognizetheexactfragranceofthesample.Weallcanstorealmost50,000differentsmells,whicharestronglytiedtothememories.
Pupils（瞳孔）donotrespondtolightalone,buttotheslightestbitofnoisearoundtoo.Thussurgeons,watchmakersandthoseprofessionalswhohavetoperformamuchdelicatejobdoprefertohaveasound-freeenvironment.Evenasmallnoisecanenlargetheirpupils,changethefocusandmaketheirvisionlessclear.
Eachandeveryoneofushasaparticularorindividualisticorcharacteristicsmell,whichisuniquetous,exceptthetwins.Thissmellisverysubtleyetcanbesensedevenbyanewborn.Itmaybeduetothissmellthatthenewbornrecognizesthepresenceofhisparentsaround.
小题1:Whatmayhappenafteryouhavehadarichlunch?