Kar, bir ya\u011f\u0131\u015f \u00e7e\u015fididir.
\n \u00c7ok say\u0131da kar kristal \u00e7e\u015fidi olmas\u0131na ra\u011fmen hepsi alt\u0131 k\u00f6\u015felidir. Kar tanelerinin kristal yap\u0131lar\u0131 birbirinin t\u0131pa t\u0131p ayn\u0131s\u0131 de\u011fildir. Mikroskopla b\u00fcy\u00fct\u00fclen kar taneleri \u00fczerinde yap\u0131lan ara\u015ft\u0131rmalarda, kristal yap\u0131lar\u0131 birbirinin ayn\u0131 olan iki kar tanesine rastlanm\u0131\u015ft\u0131r. Kar kristalleri \u00fczerinde ilk ara\u015ft\u0131rmalar\u0131 yapan ABD’li Wilson Bentley, g\u00f6rd\u00fc\u011f\u00fc muhte\u015fem sanat kar\u015f\u0131s\u0131nda adeta b\u00fcy\u00fclenmi\u015f ve elli y\u0131l boyunca s\u00fcrekli kar kristali foto\u011fraf\u0131 \u00e7ekmi\u015ftir. Elde etti\u011fi 6000 resim i\u00e7inde kristal yap\u0131lar\u0131 birbirinin ayn\u0131 olan iki kar tanesine rastlayamam\u0131\u015ft\u0131r. Daha sonralar\u0131 di\u011fer bilim adamlar\u0131n\u0131n s\u00fcrd\u00fcrd\u00fc\u011f\u00fc \u00e7al\u0131\u015fmalar neticesinde \u015fimdiye kadar kar tanecikleri aras\u0131nda ayn\u0131 b\u00fcy\u00fckl\u00fckte, ayn\u0131 \u015fekilde ve ayn\u0131 say\u0131da su molek\u00fcl\u00fc ihtiva eden iki kristal bile bulunamam\u0131\u015ft\u0131r.<\/p>\n
\u00c7aplar\u0131 2-4 mm, a\u011f\u0131rl\u0131klar\u0131 ise yakla\u015f\u0131k 0,005 gram olan kar tanecikleri havan\u0131n g\u00f6sterdi\u011fi diren\u00e7 sebebiyle s\u00fcz\u00fclerek (limit h\u0131zla) yere inerler. Bu inme s\u0131ras\u0131nda tanecikler birbirlerini ittiklerinden yap\u0131\u015fmazlar. \u00d6zelliklerini koruyarak yere inerler. Bunlar g\u00fcne\u015f \u0131\u015f\u0131\u011f\u0131n\u0131 tamamen yans\u0131tt\u0131klar\u0131 i\u00e7in beyaz olarak g\u00f6r\u00fcl\u00fcrler. Kar ya\u011f\u0131\u015f\u0131 genellikle hava s\u0131cakl\u0131\u011f\u0131 -4 \u00b0C il\u00e2 -20 \u00b0C aras\u0131ndayken olur. Bu ya\u011f\u0131\u015f, s\u0131cakl\u0131k s\u0131f\u0131r\u0131n alt\u0131nda birka\u00e7 derece oldu\u011funda a\u011f\u0131r, nemli, ebatlar\u0131 bir santimetreye ula\u015fan par\u00e7alar halinde ger\u00e7ekle\u015fir. \u201cLapa lapa kar ya\u011fmas\u0131\u201d tabiri bu durum i\u00e7in kullan\u0131l\u0131r. Atmosfer ile topra\u011f\u0131n s\u0131cakl\u0131klar\u0131 e\u015fit olursa y\u00fczeye ula\u015fan kar hemen erimez. Toprak s\u0131cakl\u0131\u011f\u0131 atmosfer s\u0131cakl\u0131\u011f\u0131n\u0131n \u00fczerinde ise, yere d\u00fc\u015fen kar k\u0131sa s\u00fcrede erir.
\n D\u00fcnya \u00fczerinde bir b\u00f6lgede, kar ya\u011f\u0131\u015f\u0131 olma ihtimali, o b\u00f6lgenin ekvatordan uzakl\u0131k ve deniz seviyesinden y\u00fcksekli\u011fi ile do\u011fru orant\u0131l\u0131d\u0131r. Buna ra\u011fmen \u0131l\u0131man b\u00f6lgelerin kara iklimi g\u00f6r\u00fclen k\u0131s\u0131mlar\u0131nda, ekvatordan uzakl\u0131k ve denizden y\u00fckseklik \u015fartlar\u0131 yeterli durumda olmasa bile, kar ya\u011f\u0131\u015f\u0131 g\u00f6r\u00fcl\u00fcr. Yap\u0131lan ara\u015ft\u0131rmalarda b\u00fct\u00fcn ya\u011f\u0131\u015flar\u0131n alt\u0131 veya sekizde birinin kar olarak ger\u00e7ekle\u015fti\u011fi anla\u015f\u0131lm\u0131\u015ft\u0131r. Kar\u0131n, tar\u0131m topra\u011f\u0131n\u0131 korumas\u0131 ve nemli tutmas\u0131nda \u00f6nemi b\u00fcy\u00fckt\u00fcr. Kar, yery\u00fcz\u00fc ve yeralt\u0131 su rezervlerinin ana kayna\u011f\u0131d\u0131r.
\n Kar, -8 \u00b0C\u2019de, bitkilerin \u00fczerinde ince bir hava tabakas\u0131 b\u0131rakarak, bu b\u00f6lgeyi 0 \u00b0C olacak \u015fekilde \u00f6rter. K\u0131\u015f boyunca toprak ve bitkileri donmaktan koruyan kar, ilkbaharda s\u0131cakl\u0131\u011f\u0131n artmas\u0131yla eriyerek nehirlere ula\u015f\u0131r. Ayr\u0131ca k\u0131\u015f\u0131n ya\u011fan ve d\u00f6rtte \u00fc\u00e7\u00fc \u00fcst k\u0131s\u0131mlarda kalan kar, yaz kurakl\u0131\u011f\u0131na kar\u015f\u0131 da topra\u011f\u0131 ve bitkileri korumu\u015f olur. Karda bulunan amonyak, kar erimesiyle birlikte toprakta kal\u0131r. Bu amonyak, azot bakterileri taraf\u0131ndan kalsiyum nitrat gibi azot tuzlar\u0131na \u00e7evrilerek bitkilerin azot ihtiyac\u0131n\u0131 kar\u015f\u0131lar.<\/p>\n
Kar tanelerinin kristalizasyonu
\n Genellikle \u00e7aplar\u0131 2-4 mm, a\u011f\u0131rl\u0131klar\u0131 ise yakla\u015f\u0131k 0,005 gram’d\u0131r. Kar tanesi, olu\u015fmaya ba\u015flad\u0131\u011f\u0131 zamanki s\u0131cakl\u0131\u011fa ve neme g\u00f6re \u015fekil al\u0131r. Nadiren yakla\u015f\u0131k -2 \u00b0 C derecede kar taneleri simetrik \u00fc\u00e7gen \u015feklinde olu\u015fur. Kar tanelerinin \u00e7o\u011fu \u00e7\u0131plak g\u00f6zle d\u00fczensiz g\u00f6r\u00fcn\u00fcr, ama resimlerde \u015fekillerin \u00e7ekicili\u011fi nedeniyle m\u00fckemmele yak\u0131n g\u00f6r\u00fclebilir. \u0130nce ve d\u00fcz \u015fekilli kristaller hava 0 \u00b0 C ila -3 \u00b0 C aras\u0131nda olu\u015fur. -3 \u00b0 C ila -8 \u00b0 C aras\u0131nda kristaller i\u011fne, i\u00e7i bo\u015f s\u00fctunlar veya prizmalar (uzun ince kalem \u015fekli) \u015feklinde olu\u015fur. -8 \u00b0 C. ila -22 \u00b0 C aras\u0131nda tabak \u015fekline d\u00f6ner ve bazen dall\u0131 ve dendritik \u00f6zellikler ta\u015f\u0131r. S\u0131v\u0131 ile buz aras\u0131ndaki buhar bas\u0131nc\u0131n\u0131n maksimum fark\u0131 yakla\u015f\u0131k -15 \u00b0 C derecede g\u00f6r\u00fcl\u00fcr ve bu \u0131s\u0131da kristaller s\u0131v\u0131 damlac\u0131klar\u0131n\u0131 t\u00fcketerek h\u0131zla b\u00fcy\u00fcrler. -22 \u00b0 C derece alt\u0131nda kristaller s\u00fctun \u015fekline girer ancak \u00e7ok daha karma\u015f\u0131k b\u00fcy\u00fcme modellerine de sahiptir. S\u00fctunlar, d\u00fczlemler, yan-d\u00fczlemler, kur\u015fun-rozetler gibi \u015fekiller olu\u015fur. E\u011fer bir kristal yakla\u015f\u0131k \u22125 \u00b0C derecede s\u00fctun \u015feklinde bir b\u00fcy\u00fcme e\u011filiminde ise, bu s\u00fctunlar daha s\u0131cak bir havaya rastlad\u0131\u011f\u0131nda s\u00fctunun sonunda bir tabak-plaka veya dendritik \u015fekiller olu\u015fur, ve bu kristallere “\u015fapkal\u0131 s\u00fctun” denir.<\/p>\n","protected":false},"excerpt":{"rendered":"
Kar, bir ya\u011f\u0131\u015f \u00e7e\u015fididir. \u00c7ok say\u0131da kar kristal \u00e7e\u015fidi olmas\u0131na ra\u011fmen hepsi alt\u0131 k\u00f6\u015felidir. Kar tanelerinin kristal yap\u0131lar\u0131 birbirinin t\u0131pa t\u0131p ayn\u0131s\u0131 de\u011fildir. Mikroskopla b\u00fcy\u00fct\u00fclen kar taneleri \u00fczerinde yap\u0131lan ara\u015ft\u0131rmalarda, kristal yap\u0131lar\u0131 birbirinin ayn\u0131 olan iki kar tanesine rastlanm\u0131\u015ft\u0131r. Kar kristalleri \u00fczerinde ilk ara\u015ft\u0131rmalar\u0131 yapan ABD’li Wilson Bentley, g\u00f6rd\u00fc\u011f\u00fc muhte\u015fem sanat kar\u015f\u0131s\u0131nda adeta b\u00fcy\u00fclenmi\u015f ve …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1403,1406],"tags":[2273,10260,3062],"class_list":["post-4747","post","type-post","status-publish","format-standard","hentry","category-odevler","category-sosyal-bilgiler-odevleri","tag-bitkiler","tag-kar-nedir-nasil-olusur","tag-nem"],"_links":{"self":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/posts\/4747","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/comments?post=4747"}],"version-history":[{"count":0,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/posts\/4747\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/media?parent=4747"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/categories?post=4747"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/tags?post=4747"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}