https://croatianschoolsydney.com/index.php?action=history&feed=atom&title=Sat 2026-05-24T17:10:14Z Povijest promjena ove stranice na wikiju MediaWiki 1.36.2 https://croatianschoolsydney.com/index.php?title=Sat&diff=8750&oldid=prev 2021-07-16T00:32:21Z

<p>Bot: Automatski unos stranica</p> <p><b>Nova stranica</b></p><div>&lt;!--'''Sat'''--&gt;{{redirect|Sat|druga značenja|[[Sat (razdvojba)]]}}<br /> [[datoteka:AnalogClockAnimation1 2hands 1h in 6sec.gif|mini|Animacija analognog sata.|200x200px]]<br /> '''Sat''' (simbol: h) je [[mjerna jedinica]] za [[vrijeme (fizika)|vrijeme]]. Sat nije [[SI sustav|SI]] jedinica, no prihvaćena je upotreba sata uz jedinice SI sustava.<br /> == Definicija ==<br /> 1 h = 60 [[minuta]]= 3600 [[sekunda|s]]<br /> <br /> == Povijest ==<br /> <br /> Sat je prvi put definiran u starom [[Egipat|Egiptu]] kao 1/24 [[dan]]a, prema njihovom brojevnom sustavu (baziranom na brojanju zglobova na prstima obje ruke).<br /> <br /> Moderna definicija sata je ''[[mjerna jedinica]] za [[vrijeme (fizika)|vrijeme]] jednaka 60 [[minuta]] ili 3600 [[sekunda]]''. Sat je približno jednak 1/24 srednjeg [[Sunčev dan|Sunčevog dana]] na Zemlji.<br /> <br /> Ranije definicije sata:<br /> <br /> '''Dvanaestina vremena od izlaska do zalaska Sunca'''<br /> <br /> Prema ovoj definiciji, ljetni su sati bili duži, a zimski kraći. Dužina sati je, osim o [[zemljopisna širina|zemljopisnoj širini]], ovisila čak i o vremenskim prilikama (koje utječu na [[atmosfera|atmosferski]] [[indeks refrakcije]], a time i na vremena izlaska i zalaska Sunca). Ovi se sati zbog toga ponekad nazivaju ''nejednaki sati''.<br /> <br /> Stari [[Rimski imperij|Rimljani]] i [[stara Grčka|Grci]] slijedili su ovu definiciju i podijelili [[noć]] u 3 ili 4 smjene. Kasnije je i noć podijeljena u 12 dijelova.<br /> <br /> Satni mehanizam koji je pokazivao ovo vrijeme morao se svaki dan podešavati (npr. mijenjanjem duljine [[njihalo|njihala]]) ili je morao pokazivati položaj Sunca na ekliptici (vidi [[Praški astronomski sat]]).<br /> <br /> '''Dvadesetčetvrti dio [[Sunčevo vrijeme|prividnog sunčevog dana]]'''<br /> <br /> Sunčev dan je period izmedju dva podneva, dva zalaska Sunca i slično. Kao posljedica ovakvog definiranja sata, sati su se vrlo polako mijenjali tijekom godine, s promjenama trajanja prividnog sunčevog dana kroz [[godina|godinu]]. Satni mehanizam je trebalo podešavati nekoliko puta na mjesec. <br /> <br /> '''Dvadesetčetvrti dio srednjeg [[Sunčev dan|sunčevog dana]]'''<br /> <br /> Kod ovakve definicije sata, satni mehanizam nikada nije trebalo podešavati. No, s otkrićem da se zemljina [[rotacija]] postepeno usporava (zbog međudjelovanja Zemlje s [[Mjesec]]om), odlučeno je da se i ova definicija napusti.<br /> <br /> == Brojanje sati ==<br /> {{sectionStub|, Fizika}}<br /> {{prijevod, zakomentirano}}<br /> &lt;!--<br /> Every definition of the hour came with its own starting point for counting the hours.<br /> * In antiquity, the counting of hours started with sunrise. So, sunrise is always exactly at the ''beginning'' of the 1st hour, noon at the end of the 6th hour, and sunset exactly at the end of the 12th hour. This means the length of hours varies with the season.<br /> * In the so-called ''Italian time,'' the first hour starts at sunset (or the end of dusk, i. e., 1/2 hour after sunset, depending on local custom). The hours are numbered from 0 to 23. So, the Sun rises at Lugano in December around 14:46 and noon is around 19:23; in June, the Sun rises already at 7:51 and noon is around 15:55. Sunset is always at 24:00. This manner of counting hours has the advantage that everyone can easily read the clock to see how much time they will have to finish their day's work without artificial light. It was introduced in [[Italy]] during the [[14th century]] and lasted until the mid-[[18th century]], or in some regions until the mid-[[19th century]]. It was also used in [[Poland]] and [[Bohemia]] until the [[17th century]].<br /> * In the modern [[12-hour clock]], counting the hours starts at midnight and restarts at noon. Hours are numbered 12, 1, 2, ..., 11. [[solar time|Solar noon]] is always close to 12 [[P.M.]] (''post meridiem'', ''after noon''), differing according to the [[equation of time]] (differing by up to about 15 min either way). At the [[equinox]]es, sunrise is around 6 [[A.M.]] (''ante meridiem'', ''before noon''), and sunset around 6 PM.<br /> * In the modern [[24-hour clock]], counting the hours starts at midnight, and hours are numbered from 0 to 23. Solar noon is always close to 12:00 (again differing according to the equation of time). At the equinoxes, sunrise is around 06:00, and sunset around 18:00.<br /> <br /> Sunrise and sunset are much more conspicuous points in day than noon or midnight; starting to count then is much easier than starting at noon or midnight. With modern astronomical equipment (and the telegraph or similar means to transfer a time signal in a split-second), this issue is no longer relevant.<br /> <br /> [[Sundial]]s often show the hour length and count according to some of the older definitions and countings.<br /> <br /> The division of the day into 12 hours dates back to the [[Sumerians]]. There are probably 12 hours because there are approximately 12 lunar months in a solar year. Symmetries of this sort are common in ancient units of measurement.<br /> --&gt;<br /> <br /> == Poveznice ==<br /> * [[sekunda]]<br /> * [[minuta]]<br /> * [[dan]]<br /> * [[godina]]<br /> <br /> [[Kategorija:Vremenske jedinice]]<br /> {{Mrva-fiz}}</div>

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