{"id":2624,"date":"2015-03-24T09:28:50","date_gmt":"2015-03-24T08:28:50","guid":{"rendered":"http:\/\/blocs.xtec.cat\/cdacansantoi\/?p=2624"},"modified":"2017-07-06T14:18:58","modified_gmt":"2017-07-06T12:18:58","slug":"els-aparells-meteorologics-el-psicrometre","status":"publish","type":"post","link":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/articles-aparells-meteorologia\/els-aparells-meteorologics-el-psicrometre\/","title":{"rendered":"Els aparells meteorol\u00f2gics: el psicr\u00f2metre"},"content":{"rendered":"<p><span style=\"color: #3366ff;\"><strong>Per a qu\u00e8 serveix?<br \/>\n<\/strong><\/span>Un psicr\u00f2metre \u00e9s un aparell que\u00a0 mesura la humitat relativa de l&#8217;aire.<\/p>\n<p style=\"text-align: justify;\"><strong><span style=\"color: #3366ff;\">Com funciona?<\/span><br \/>\n<\/strong>El psicr\u00f2metre consta de dos term\u00f2metres de precisi\u00f3 mitjana (amb graduacions de 0,5\u00baC), col\u00b7locats l&#8217;un al costat de l&#8217;altre:<img loading=\"lazy\" decoding=\"async\" class=\"alignright wp-image-2702\" src=\"http:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2015\/03\/psicrometre_mural-e1478511217467.png\" alt=\"psicrometre_mural\" width=\"319\" height=\"421\" \/><\/p>\n<ul style=\"list-style-type: square;\">\n<li style=\"text-align: justify;\"><strong>El term\u00f2metre sec<\/strong>: \u00e9s un term\u00f2metre convencional que mesura la temperatura de l&#8217;aire.<\/li>\n<li style=\"text-align: justify;\"><strong>El term\u00f2metre humit<\/strong>: al seu bulb s&#8217;hi troba una gasa permanentment mullada que absorbeix l&#8217;aigua d&#8217;un dip\u00f2sit ple d&#8217;aigua destil\u00b7lada.<br \/>\nLa temperatura que marca dep\u00e8n de la quantitat d&#8217;aigua que s&#8217;evapora al seu bulb, que ser\u00e0 major o menor en funci\u00f3 de la humitat que cont\u00e9 l&#8217;aire del seu voltant. Per exemple:<\/p>\n<ul style=\"list-style-type: circle;\">\n<li style=\"text-align: justify;\">Si l&#8217;aire \u00e9s molt sec (cont\u00e9 poc vapor d&#8217;aigua) s&#8217;evaporar\u00e0 molta aigua de la gasa i, per tant, prendr\u00e0 molta calor al term\u00f2metre humit que marcar\u00e0 una temperatura notablement m\u00e9s baixa que la del term\u00f2metre sec.<\/li>\n<li style=\"text-align: justify;\">Si l&#8217;aire \u00e9s molt humit (cont\u00e9 molt vapor d&#8217;aigua) s&#8217;evaporar\u00e0 molt poca aigua de la gasa i, per tant, prendr\u00e0 molt poca calor al term\u00f2metre humit que marcar\u00e0 una temperatura gaireb\u00e9 igual a la del term\u00f2metre sec<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p style=\"text-align: justify;\">D&#8217;altra banda, com que la quantitat de vapor d&#8217;aigua que pot contenir una massa d&#8217;aire dep\u00e8n de la seva temperatura (a m\u00e9s temperatura, m\u00e9s vapor d&#8217;aigua), el valor d&#8217;humitat relativa variar\u00e0 tamb\u00e9 en funci\u00f3 d&#8217;aquest par\u00e0metre.<\/p>\n<p style=\"text-align: justify;\">Per tal de tenir presents totes aquestes variables disposem d&#8217;unes <a href=\"http:\/\/www.acom.cat\/utilitats\/humitat.html\" target=\"_blank\">taules psicrom\u00e8triques<\/a> que faciliten el c\u00e0lcul de la humitat relativa de l&#8217;aire basat en la difer\u00e8ncia dels dos term\u00f2metres i de la temperatura de l&#8217;aire en el moment en que es fa la mesura.<\/p>\n<p style=\"text-align: justify;\"><strong><span style=\"color: #3366ff;\">Com ho mesurem?<\/span><\/strong><\/p>\n<p style=\"text-align: justify;\"><strong>Preparaci\u00f3 de l&#8217;aparell.<\/strong><\/p>\n<p style=\"text-align: justify;\">1. Omplim el dip\u00f2sit amb aigua destil\u00b7lada i hi introdu\u00efm la gasa de manera que quedi ben xopa.<br \/>\n2. Deixem el psicr\u00f2metre a l&#8217;aire lliure, en un lloc ventilat \u00a0per\u00f2 protegit del sol i de la pluja.<br \/>\n3. Hem d&#8217;esperar una bona estona a que la gasa quedi ben xopa.<\/p>\n<p style=\"text-align: justify;\"><strong>Lectura de la humitat relativa de l&#8217;aire<\/strong><\/p>\n<p style=\"text-align: justify;\">1. Mesurem la temperatura del term\u00f2metre sec i l&#8217;anotem.<br \/>\n2. Mesurem la temperatura del term\u00f2metre humit i tamb\u00e9 l&#8217;anotem.<br \/>\n3. Calculem la difer\u00e8ncia dels dos valors anteriors.<br \/>\n4. Consultem<a href=\"http:\/\/www.acom.cat\/utilitats\/humitat.html\" target=\"_blank\"> la taula psicrom\u00e8trica<\/a> per obtenir el valor d&#8217;humitat relativa de l&#8217;aire.<\/p>\n<p style=\"text-align: justify;\">Exemple:<br \/>\nLa mesura del term\u00f2metre sec \u00e9s de\u00a0 20 \u00baC<br \/>\nLa mesura del term\u00f2metre humit \u00e9s de\u00a0 18,5 \u00baC<br \/>\nLa difer\u00e8ncia de temperatures \u00e9s de 1,5 \u00baC<br \/>\nSi consultem la<a href=\"http:\/\/www.acom.cat\/utilitats\/humitat.html\" target=\"_blank\"> taula psicrom\u00e8trica<\/a> obtenim una humitat relativa de l&#8217;aire de 86%<\/p>\n<p style=\"text-align: justify;\"><span style=\"color: #3366ff;\"><strong>En quines unitats es mesura?<\/strong><\/span><\/p>\n<p style=\"text-align: justify;\">La humitat relativa s&#8217;expressa en tants per cents o percentatge (%)<\/p>\n<p style=\"text-align: justify;\"><span style=\"color: #3366ff;\"><strong>Interpretaci\u00f3 dels valors d&#8217;humitat<\/strong><\/span><\/p>\n<p style=\"text-align: justify;\">Trobareu aquesta informaci\u00f3 a l&#8217;<a title=\"Els aparells meteorol\u00f2gics: l\u2019higr\u00f2metre\" href=\"http:\/\/blocs.xtec.cat\/cdacansantoi\/2014\/11\/13\/els-aparells-meteorologics-lhigrometre\/\" target=\"_blank\">article de divulgaci\u00f3 sobre l&#8217;higr\u00f2metre<\/a>.<\/p>\n<p style=\"text-align: justify;\"><span style=\"color: #3366ff;\"><strong><span style=\"color: #3366ff;\">Altres models de psicr\u00f2metre<\/span><\/strong><strong><br \/>\n<\/strong><\/span><\/p>\n<p><strong>El psicr\u00f2metre de carraca o psicr\u00f2metre de camp<br \/>\n<\/strong><\/p>\n<p style=\"text-align: justify;\"><a href=\"http:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2015\/03\/psicr\u00f2metre-de-camp.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft wp-image-2706\" src=\"http:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2015\/03\/psicr\u00f2metre-de-camp.jpg\" alt=\"psicr\u00f2metre de camp\" width=\"207\" height=\"290\" \/><\/a>Presenta la mateixa estructura i funcionament que el psicr\u00f2metre convencional (tamb\u00e9 anomenat, mural). Les difer\u00e8ncies que el converteixen en un aparell f\u00e0cilment transportable i de r\u00e0pid \u00fas s\u00f3n:<\/p>\n<ul style=\"list-style-type: circle;\">\n<li style=\"text-align: justify;\">Els term\u00f2metres s\u00f3n m\u00e9s petits i estrets (ocupa menys espai).<\/li>\n<li style=\"text-align: justify;\">L&#8217;aigua del dip\u00f2sit s&#8217;omple en el moment de la lectura; tamb\u00e9 es mulla\u00a0 la gasa.<\/li>\n<li style=\"text-align: justify;\">T\u00e9 un m\u00e0nec plegable que serveix per fer voltar l&#8217;aparell a gran velocitat de manera que afavorim l&#8217;evaporaci\u00f3 de l&#8217;aigua de la gasa per tal d&#8217;obtenir una lectura r\u00e0pida.<\/li>\n<\/ul>\n<p><strong>El psicr\u00f2metre d&#8217;Asmann o d&#8217;aspiraci\u00f3<\/strong><\/p>\n<p><a href=\"http:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2015\/03\/psicr\u00f2metre-Asmann.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft wp-image-2713\" src=\"http:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2015\/03\/psicr\u00f2metre-Asmann.jpg\" alt=\"psicr\u00f2metre Asmann\" width=\"76\" height=\"296\" \/><\/a>Aquest psicr\u00f2metre, a difer\u00e8ncia dels anteriors, \u00e9s molt m\u00e9s prec\u00eds i <a href=\"http:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2015\/03\/psicrometro-asmann-mecanisme.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignright wp-image-2714 \" src=\"http:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-content\/uploads\/usu1385\/2015\/03\/psicrometro-asmann-mecanisme-150x150.jpg\" alt=\"psicrometro asmann mecanisme\" width=\"165\" height=\"165\" \/><\/a>serveix per a calibrar altres psicr\u00f2metres o higr\u00f2metres.<\/p>\n<p>Els seus term\u00f2metres tenen una precisi\u00f3 de 0,2 \u00baC i es realitza una ventilaci\u00f3 for\u00e7ada d&#8217;aire que facilita i accelera l&#8217;evaporaci\u00f3 de l&#8217;aigua del term\u00f2metre humit.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><span style=\"color: #3366ff;\"><strong>El taller: constru\u00efm un psicr\u00f2metre<\/strong><br \/>\n<\/span><\/p>\n<p><a href=\"http:\/\/librodigital.oupe.es\/oxed\/0560891001300218339\/plantilla\/ebook\/data\/pdf\/750-construccion-de-un-psicometro-a.pdf\" target=\"_blank\">Web que explica com construir f\u00e0cilment un psicr\u00f2metre<\/a> (Oxford Univeristy Press\/ en castell\u00e0)<\/p>\n<p><strong><span style=\"color: #3366ff;\">Refer\u00e8ncies i<\/span><\/strong><span style=\"color: #3366ff;\"><strong> enlla\u00e7os<br \/>\n<\/strong><\/span><\/p>\n<ul>\n<li><a title=\"Els aparells meteorol\u00f2gics: l\u2019higr\u00f2metre\" href=\"http:\/\/blocs.xtec.cat\/cdacansantoi\/2014\/11\/13\/els-aparells-meteorologics-lhigrometre\/\" target=\"_blank\">Article sobre l&#8217;higr\u00f2metre, en aquest mateix web.<\/a><\/li>\n<li>Activitats del Camp d&#8217;Aprenentatge relacionades:\n<ul>\n<li><a title=\"Quin temps fa? (CMP)\" href=\"http:\/\/blocs.xtec.cat\/cdacansantoi\/quin-temps-fa\/\" target=\"_blank\">Quin temps fa? (cicle mitj\u00e0 de prim\u00e0ria)<\/a><\/li>\n<li><a title=\"Observaci\u00f3 i mesura del temps atmosf\u00e8ric (CSP)\" href=\"http:\/\/blocs.xtec.cat\/cdacansantoi\/observacio-i-mesura-temps-atmosferic-csp\/\" target=\"_blank\">Observaci\u00f3 i mesura del temps atmosf\u00e8ric (cicle superior de prim\u00e0ria)<\/a><\/li>\n<li><a title=\"Observaci\u00f3 i mesura del temps atmosf\u00e8ric. ESO\" href=\"http:\/\/blocs.xtec.cat\/cdacansantoi\/observacio-i-mesura-del-temps-atmosferic-eso\/\" target=\"_blank\">Observaci\u00f3 i mesura del temps atmosf\u00e8ric (ESO)<\/a><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<ul style=\"list-style-type: square;\">\n<li><a title=\"Meteorologia\" href=\"http:\/\/blocs.xtec.cat\/cdacansantoi\/meteorologi\/\" target=\"_blank\">Dades de l&#8217;estaci\u00f3 meteorol\u00f2gica digital de Can Santoi<\/a><\/li>\n<li><a href=\"http:\/\/blocs.xtec.cat\/cdacansantoi\/programes-de-suport\/\" target=\"_blank\">Meteomaps: <\/a>programari per a confegir mapes del temps<\/li>\n<li><a href=\"http:\/\/ca.wikipedia.org\/wiki\/Psicr%C3%B2metre\" target=\"_blank\">Viquip\u00e8dia<\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Per a qu\u00e8 serveix? Un psicr\u00f2metre \u00e9s un aparell que\u00a0 mesura la humitat relativa de l&#8217;aire. Com funciona? El psicr\u00f2metre consta de dos term\u00f2metres de precisi\u00f3 mitjana (amb graduacions de 0,5\u00baC), col\u00b7locats l&#8217;un al costat de l&#8217;altre: El term\u00f2metre sec: \u00e9s un term\u00f2metre convencional que mesura la temperatura de l&#8217;aire. El term\u00f2metre humit: al seu [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":8804,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[376],"tags":[329,330],"class_list":["post-2624","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-articles-aparells-meteorologia","tag-humitat-relativa","tag-psicrometre"],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/posts\/2624","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/comments?post=2624"}],"version-history":[{"count":1,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/posts\/2624\/revisions"}],"predecessor-version":[{"id":8805,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/posts\/2624\/revisions\/8805"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/media\/8804"}],"wp:attachment":[{"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/media?parent=2624"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/categories?post=2624"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/tags?post=2624"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}