{"id":2116,"date":"2014-08-07T13:27:21","date_gmt":"2014-08-07T11:27:21","guid":{"rendered":"http:\/\/www.zsvltava.cz\/fyzika\/?p=2116"},"modified":"2024-11-19T14:53:31","modified_gmt":"2024-11-19T13:53:31","slug":"povidani-o-magnetu","status":"publish","type":"post","link":"https:\/\/www.zsvltava.cz\/fyzika\/?p=2116","title":{"rendered":"Jak funguje magnet?"},"content":{"rendered":"<p><iframe loading=\"lazy\" width=\"640\" height=\"400\" src=\"\/\/www.youtube.com\/embed\/hFAOXdXZ5TM?list=UUUHW94eEFW7hkUMVaZz4eDg\" frameborder=\"0\" allowfullscreen><\/iframe><\/p>\n<p><strong>P\u0159epis obsahu video p\u0159\u00edsp\u011bvku:<\/strong><\/p>\n<p>Kdy\u017e vezmete kus d\u0159eva a p\u0159ilo\u017e\u00edte ho k jin\u00e9mu kusu d\u0159eva&#8230; nic se nestane. kdy\u017e vezmete kus \u017euly a polo\u017e\u00edte ho vedle jin\u00e9ho kamene&#8230; po\u0159\u00e1d nic. Ale kdy\u017e vezmete tenhle kus \u017eeleza a polo\u017e\u00edte ho vedle jin\u00e9ho kusu \u017eeleza&#8230; kouzlo!<br \/>\nTedy, magnet.<\/p>\n<p>Magnetick\u00e9 p\u0159edm\u011bty mohou magicky p\u0159itahovat na dlouh\u00e9 vzd\u00e1lenosti proto\u017ee generuj\u00ed magnetick\u00e9, kter\u00e9 se neviditeln\u011b rozprost\u00edr\u00e1 kolem objektu. Ale z\u00e1hada je v tom: odkud se bere magnetick\u00e9 pole?<\/p>\n<p>Derekk: to je jednoduch\u00e9, Henry! U\u017e dlouho v\u00edme, \u017ee elekt\u0159ina a magnetismus jsou ve skute\u010dnosti dv\u011b strany jedn\u00e9 mince, podobn\u011b jako hmota a energie nebo \u010das a prostor, a mohou se vz\u00e1jemn\u011b transformovat. Ve skute\u010dnosti je magnetick\u00e9 pole jen t\u00edm v co se prom\u011bn\u00ed elektrick\u00e9 pole kdy\u017e se elektricky nabit\u00fd objekt za\u010dne pohybovat!<\/p>\n<p>Henry: T\u00edm se d\u00e1 vysv\u011btlit pro\u010d proud elektron\u016f proch\u00e1zej\u00edc\u00ed dr\u00e1tem zp\u016fsob\u00ed pohyb st\u0159elky kompasu nebo jak proudy ve vn\u011bj\u0161\u00edm zemsk\u00e9m j\u00e1dru vytv\u00e1\u0159ej\u00ed geomagnetick\u00e9 pole&#8230; ale ty\u010dov\u00fd magnet nebo st\u0159elka kompasu jsou p\u0159ece jen kousky kovu, kter\u00fdmi neproch\u00e1z\u00ed \u017e\u00e1dn\u00fd proud.<\/p>\n<p>Derek: A nebo ne? Na mikroskopick\u00e9 \u00farovni spousty elektron\u016f kmitaj\u00ed v atomech a molekul\u00e1ch tvo\u0159\u00edc\u00edch ka\u017edou pevnou l\u00e1tku.<\/p>\n<p>Henry: Spr\u00e1vn\u011b! To n\u00e1s p\u0159iv\u00e1d\u00ed ke skv\u011bl\u00e9mu zji\u0161t\u011bn\u00ed &#8211; Magnetick\u00e9 chov\u00e1n\u00ed jak\u00e9hokoli b\u011b\u017en\u00e9ho p\u0159edm\u011btu je ovliv\u0148ov\u00e1no fascinuj\u00edc\u00ed kombinac\u00ed jev\u016f sahaj\u00edc\u00edch od \u00farovn\u011b \u010d\u00e1stic k atom\u016fm, soubor\u016fm atom\u016f a shluk\u016fm soubor\u016f atom\u016f. Nejd\u0159\u00edv jednotliv\u00e9 \u010d\u00e1stice.<\/p>\n<p>Narozd\u00edl od b\u011b\u017en\u00fdch projev\u016f gravitace a elekt\u0159iny, permanentn\u00ed magnety mohou b\u00fdt pln\u011b pochopeny jen jako jev kvantov\u00e9 mechaniky. Velmi podobn\u011b jako \u010d\u00e1stice typu elektrony a kvarky maj\u00ed z\u00e1kladn\u00ed vlastnosti zvan\u00e9 hmotnost a elektrick\u00fd n\u00e1boj, v\u011bt\u0161ina \u010d\u00e1stic m\u00e1 DAL\u0160\u00cd jinou vnit\u0159n\u00ed vlastnost zvanou &#8222;malink\u00fd magnet&#8220;. D\u011bl\u00e1m si legraci, \u0159\u00edk\u00e1 se tomu &#8222;vlastn\u00ed magnetick\u00fd moment,&#8220; ale fakticky je to jen technick\u00e1 hatmatilka \u0159\u00edkaj\u00edc\u00ed, \u017ee \u010d\u00e1stice s elektrick\u00fdm n\u00e1bojem je z\u00e1rove\u0148 TAK\u00c9 malink\u00fd magnet.<\/p>\n<p>Derek: Chcete-li v\u011bd\u011bt PRO\u010c jsou malink\u00e9 magnety, m\u016f\u017eete se v prvn\u00ed \u0159ad\u011b pt\u00e1t PRO\u010c \u010d\u00e1stice maj\u00ed n\u00e1boj nebo pro\u010d se p\u0159edm\u011bty s energi\u00ed a hybnost\u00ed gravita\u010dn\u011b p\u0159itahuj\u00ed? Nikdo nev\u00ed&#8230; V\u00edme jen, \u017ee je to pravda\/\u017ee takto funguje n\u00e1\u0161 vesm\u00edr.<\/p>\n<p>Henry: P\u0159esn\u011b tak. A od roku 1920, v\u00edme, \u017ee ka\u017ed\u00fd elektron nebo proton<br \/>\nje v podstat\u011b malink\u00fd magnet. Co\u017e n\u00e1s p\u0159iv\u00e1d\u00ed na \u00farove\u0148 atom\u016f.<br \/>\nAtom je houf kladn\u011b nabit\u00fdch proton\u016f s houfem z\u00e1porn\u011b nabit\u00fdch elektron\u016f<br \/>\nKmitaj\u00edc\u00edch kolem nich. Malink\u00e9 magnety proton\u016f jsou zhruba tis\u00edckr\u00e1t slab\u0161\u00ed ne\u017e ty v elektronech tak\u017ee atomov\u00e9 j\u00e1dro nem\u00e1 skoro \u017e\u00e1dn\u00fd efekt na magnetismus atomu jako celku.<\/p>\n<p>Derek: A m\u016f\u017eete si domyslet, \u017ee d\u00edky tomu, \u017ee mnoho (a\u010dkoli ne v\u0161echny) elektrony se tak\u00e9 pohybuj\u00ed, jako proud v dr\u00e1tu, budou generovat magnetick\u00e9 pole d\u00edky tomuto pohybu. Samoz\u0159ejm\u011b to tak je a takov\u00e9 pole se naz\u00fdv\u00e1 &#8222;orbit\u00e1ln\u00ed&#8220; magnetick\u00e9 pole.<\/p>\n<p>Henry: Ov\u0161em tato pole obvykle nep\u0159isp\u00edvaj\u00ed k magnetick\u00e9mu poli atomu. Pod\u00edvejme<br \/>\nse pro\u010d: Elektrony v atomech p\u0159esn\u011b a komplikovan\u011b popisuje kvantov\u00e1 mechanika, ale podstata cel\u00e9ho p\u0159\u00edb\u011bhu je v tom, \u017ee elektrony se soust\u0159e\u010fuj\u00ed ve slupk\u00e1ch kolem j\u00e1dra. Elektrony v ka\u017ed\u00e9 obsazen\u00e9 slupce l\u00e9taj\u00ed rovnom\u011brn\u011b v\u0161emi sm\u011bry a proudy, kter\u00e9 tvo\u0159\u00ed, se vz\u00e1jemn\u011b ru\u0161\u00ed tak\u017ee negeneruj\u00ed \u017e\u00e1dn\u00e9 magnetick\u00e9 pole. Tyto elektrony tak\u00e9 p\u0159edstavuj\u00ed p\u00e1ry jejich\u017e malink\u00e9 magnety sm\u011b\u0159uj\u00ed opa\u010dn\u00fdmi sm\u011bry a tak\u00e9 se ru\u0161\u00ed. Ov\u0161em ve slupk\u00e1ch zapln\u011bn\u00fdch jen z poloviny jsou v\u0161echny elektrony nesp\u00e1rovan\u00e9 a jejich mal\u00e9 magnety ukazuj\u00ed stejn\u00fdm sm\u011brem a s\u010d\u00edtaj\u00ed se. To znamen\u00e1, \u017ee je to vlastn\u00ed magnetismus elektron\u016f ve vn\u011bj\u0161\u00edch slupk\u00e1ch, co dod\u00e1v\u00e1 atomu v\u011bt\u0161inu jeho magnetick\u00e9ho pole. Tak\u017ee atomy pobl\u00ed\u017e kraj\u016f ka\u017ed\u00e9 \u0159ady periodick\u00e9 tabulky prvk\u016f, kter\u00e9 maj\u00ed pln\u00e9 (nebo t\u00e9m\u011b\u0159 zapln\u011bn\u00e9) vn\u011bj\u0161\u00ed elektronov\u00e9 slupky, nejsou p\u0159\u00edli\u0161 magnetick\u00e9. A atomy ve ST\u0158EDU ka\u017ed\u00e9 \u0159ady maj\u00ed zpola pln\u00e9 elektronov\u00e9 slupky a jsou magnetick\u00e9. Nap\u0159\u00edklad nikl, kobalt, \u017eelezo, mangan, chrom, a podobn\u011b.<\/p>\n<p>Derek: Moment, ale chrom p\u0159ece nen\u00ed magnetick\u00fd!<\/p>\n<p>Henry: Ale, p\u0159ece jen proto, \u017ee atom je magnetick\u00fd je\u0161t\u011b neznamen\u00e1, \u017ee materi\u00e1l skl\u00e1daj\u00edc\u00ed se ze spousty takov\u00fdch atom\u016f bude magnetick\u00fd. To n\u00e1s p\u0159iv\u00e1d\u00ed na \u00farove\u0148 krystal\u016f. Kdy\u017e se magnetick\u00e9 atomy formuj\u00ed dohromady aby utvo\u0159ily pevnou l\u00e1tku, maj\u00ed obecn\u011b dv\u011b mo\u017enosti. Bu\u010f si v\u0161echny navz\u00e1jem sv\u00e1 magnetick\u00e1 pole srovnaj\u00ed do stejn\u00e9ho sm\u011bru a nebo se orientace magnetick\u00e9ho pole st\u0159\u00edd\u00e1, tak\u017ee se navz\u00e1jem vyru\u0161\u00ed. Atomy zaujmou takovou pozici, kter\u00e1 vy\u017eaduje m\u00e9n\u011b energie.<\/p>\n<p>Derek: Tak proto se nap\u0159\u00edklad chov\u00e1 chrom jako velmi magnetick\u00fd atom, ale velmi nemagnetick\u00fd materi\u00e1l &#8211; proto\u017ee je to jeden z nejv\u00edce antiferomagnetick\u00fdch materi\u00e1l\u016f kter\u00e9 zn\u00e1me. Na druhou stranu \u017eelezo, kter\u00e9 dalo feromagnetismu jm\u00e9no, je podle o\u010dek\u00e1v\u00e1n\u00ed feromagnetick\u00e9. Neboli,jak b\u011b\u017en\u011b \u0159\u00edk\u00e1me: magnetick\u00e9.<\/p>\n<p>Henry: N\u011bkdy. Ta posledn\u00ed a kone\u010dn\u00e1 \u00farove\u0148 magnetismu je ta dom\u00e9nov\u00e1. Zjednodu\u0161en\u011b, dokonce i v magnetick\u00e9m materi\u00e1lu, kde magnetick\u00e9 pole atom\u016f je orientov\u00e1no stejn\u011b, je mo\u017en\u00e9, \u017ee jeden kousek tohoto materi\u00e1lu bude m\u00edt atomy srovnan\u00e9 do jedno sm\u011bru, zat\u00edmco jin\u00fd kousek bude m\u00edt v\u0161echny sv\u00e9 atomy srovnan\u00e9 do jin\u00e9ho sm\u011bru, a tak d\u00e1le.<\/p>\n<p>Derek: Pokud v\u0161echny tyto &#8222;dom\u00e9ny&#8220; maj\u00ed p\u0159ibl\u017en\u011b stejnou velikost, \u017e\u00e1dn\u00e1 z nich nem\u016f\u017ee b\u00fdt dost siln\u00e1 na to, aby p\u0159inutila ostatn\u00ed srovnat se podle n\u00ed, tak\u017ee nap\u0159\u00edklad kus \u017eeleza nemus\u00ed m\u00edt \u017e\u00e1dn\u00e9 magnetick\u00e9 pole d\u00edky v\u0161em sv\u00fdm soupe\u0159\u00edc\u00edm magnetick\u00fdm kr\u00e1lovstv\u00edm uvnit\u0159.<\/p>\n<p>Henry: Av\u0161ak pokud z vn\u011bj\u0161ku aplikujeme dostate\u010dn\u011b siln\u00e9 magnetick\u00e9 pole\/s\u00edlu\/tlak, m\u016f\u017eeme pomoci jedn\u00e9 dom\u00e9n\u011b roz\u0161\u00ed\u0159it sv\u016fj vliv na sv\u00e9 okol\u00ed,<br \/>\na tak d\u00e1l dokud nebudou v\u0161echny dom\u00e9ny sjednoceny do jednoho kr\u00e1lovstv\u00ed, v\u0161echny orientovan\u00e9 t\u00edm sam\u00fdm sm\u011brem.<\/p>\n<p>Derek: A te\u010f kone\u010dn\u011b m\u016f\u017eeme vl\u00e1dnout \u017eeleznou rukou&#8230; tedy, magnetem.<\/p>\n<p>Henry: P\u0159esn\u011b tak! Za zm\u00ednku stoj\u00ed, \u017ee magnetismus je v podstat\u011b kvantov\u00e1 vlastnost zv\u011bt\u0161en\u00e1 na velikost b\u011b\u017en\u00fdch p\u0159edm\u011bt\u016f: ka\u017ed\u00fd permanentn\u00ed magnet je p\u0159ipom\u00ednkou toho, \u017ee kvantov\u00e1 mechanika tvo\u0159\u00ed z\u00e1klad na\u0161eho vesm\u00edru &#8211; aby byl p\u0159edm\u011bt magnetick\u00fd mus\u00ed m\u00edt jednotn\u00e9 kr\u00e1lovstv\u00ed magnetick\u00fdch dom\u00e9n, z nich\u017e ka\u017ed\u00e1 je tvo\u0159ena miliardami magnetick\u00fdch atom\u016f, kter\u00e9 tak\u00e9 musej\u00ed b\u00fdt vz\u00e1jemn\u011b orientovan\u00e9 a p\u0159itom ka\u017ed\u00fd z nich m\u016f\u017ee b\u00fdt magnetick\u00fd jen pokud m\u00e1 v p\u0159ibli\u017en\u011b z poloviny zapln\u011bn\u00e9 vn\u011bj\u0161\u00ed elektronov\u00e9 slupky, tak\u017ee jejich vlastn\u00ed magnetick\u00e1 pole se mohou srovnat a nevyru\u0161\u00ed se p\u0159i tom. Nep\u0159ekvapuje, \u017ee tyto podm\u00ednky<br \/>\nje opravdu t\u011b\u017ek\u00e9 splnit, a proto existuje jen omezen\u00fd po\u010det vhodn\u00fdch materi\u00e1l\u016f, kter\u00e9 m\u016f\u017eete pou\u017e\u00edt na v\u00fdrobu magnetu.<\/p>\n<p>Derek: A NEBO m\u016f\u017eete prost\u011b nechat proch\u00e1zet elektrick\u00fd proud vodi\u010dem a vytvo\u0159it tak magnetick\u00e9 pole t\u00edmto zp\u016fsobem. <\/p>\n<p>Zdroj: <a href=\"http:\/\/www.youtube.com\/channel\/UCUHW94eEFW7hkUMVaZz4eDg\">Minute Physics, YouTube<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>P\u0159epis obsahu video p\u0159\u00edsp\u011bvku: Kdy\u017e vezmete kus d\u0159eva a p\u0159ilo\u017e\u00edte ho k jin\u00e9mu kusu d\u0159eva&#8230; nic se nestane. kdy\u017e vezmete kus \u017euly a polo\u017e\u00edte ho &#8230;. <\/p>\n","protected":false},"author":1,"featured_media":4760,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[81,13],"tags":[4,17,71],"class_list":["post-2116","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-magnetismus","category-zajimavosti","tag-magnetismus","tag-video","tag-vysvetleni"],"_links":{"self":[{"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/posts\/2116","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2116"}],"version-history":[{"count":0,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/posts\/2116\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/media\/4760"}],"wp:attachment":[{"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2116"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2116"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2116"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}