Ko kilogram inorema zvakadii? Masayendisiti akaongorora dambudziko iri rinoratidzika kuva nyore kwemazana emakore.
Muna 1795, France yakagadza mutemo waiti “giramu” “huremu hwakakwana hwemvura iri mucube ine uremu hwakaenzana nechikamu chimwe chemita patembiricha panonyunguduka aizi (kureva 0°C).” Muna 1799, masayendisiti akawana kuti huwandu hwemvura ndiyo yakanyanya kugadzikana kana kuwanda kwemvura kuri pamusoro pe4 ° C, saka tsanangudzo yekirogiramu yachinja kuita "huremu hwe1 cubic decimeter yemvura yakachena pa4 ° C. ”. Izvi zvakaburitsa pure platinum yepakutanga kilogram, kilogiramu inotsanangurwa seyakaenzana nehuremu hwayo, iyo inodaidzwa kuti archives kilogram.
Iyi kirogiramu yakachengetwa yakashandiswa sechiyereso kwemakore makumi mapfumbamwe. Muna 1889, Musangano Wekutanga Wenyika Dzepasi Pose weMetrology wakabvumira platinamu-iridium alloy replica iri padyo nekirogiramu yezvinyorwa seyepasi rose kirogiramu yepakutanga. Huremu hwe "kilogram" inotsanangurwa neplatinamu-iridium alloy (90% platinum, 10% iridium) silinda, iyo inenge 39 mm kureba uye dhayamita, uye parizvino yakachengetwa mukamuri yepasi kunze kweParis.
International yepakutanga kilogram
Kubva muZera reKuvhenekerwa, nharaunda inoongorora yakazvipira kumisikidza ongororo yepasi rose. Kunyangwe iri nzira inogoneka yekushandisa chinhu chemuviri seyeyero yekuyera, nekuti chinhu chemuviri chiri nyore kukuvadzwa neyakagadzirwa nemunhu kana zvakatipoteredza, kugadzikana kunokanganiswa, uye nharaunda yekuyera yagara ichida kusiya nzira iyi nekukurumidza. sezvinobvira.
Mushure mekunge kilogiramu yatora tsananguro yepasi rose yepakutanga kilogiramu, pane mubvunzo uyo metrologists anonetsekana nazvo: tsananguro iyi yakagadzikana sei? Ichadonha nekufamba kwenguva here?
Zvinofanira kutaurwa kuti mubvunzo uyu wakamutswa pakutanga kwetsanangudzo yehuwandu hwema unit kilogram. Semuenzaniso, apo kilogiramu yakatsanangurwa muna 1889, International Bureau of Weights and Measures yakagadzira 7 platinum-iridium alloy kilogram uremu, imwe yacho iInternational Iyo yekutanga kilogiramu inoshandiswa kutsanangura hukuru hwema kilogiramu, uye humwe huremu 6. yakagadzirwa nechinhu chimwe chete uye maitiro akafanana anoshandiswa sechipiri mabhenji kutarisa kana paine kudhiraivha nekufamba kwenguva pakati peumwe neumwe.
Panguva imwecheteyo, nekugadzirwa kwepamusoro-soro tekinoroji, tinodawo kudzikama uye kuyerwa kwakaringana. Naizvozvo, chirongwa chekutsanangura patsva chikamu chepasi rose chine zvimiro zvemuviri chakarongwa. Kushandisa maconstants kutsanangura zviyero zvekuyera zvinoreva kuti tsananguro idzi dzichazadzisa zvinodiwa nechizvarwa chinotevera chezviwanikwa zvesainzi.
Zvinoenderana nedata repamutemo reInternational Bureau of Weights and Measures, mumakore zana kubva 1889 kusvika 2014, kuenderana kwemhando yemamwe makirogiramu epakutanga uye kirogiramu yepasi rose yepakutanga yakashandurwa ne50 micrograms. Izvi zvinoratidza kuti pane dambudziko nekugadzikana kwechimiro chechimiro chemhando yemhando. Kunyangwe shanduko ye50 micrograms inonzwika idiki, ine simba guru kune mamwe maindasitiri epamusoro.
Kana izvo zvekutanga zvemuviri zvinogara zvichishandiswa kutsiva iyo kilogiramu yemuviri bhenji, kugadzikana kweiyo mizhinji unit hakuzokanganiswe nenzvimbo uye nguva. Naizvozvo, muna 2005, International Committee for Weights and Measures yakaronga hurongwa hwekushandiswa kwezvisingaguri zvemuviri kutsanangura mamwe mayuniti akakosha eInternational System of Units. Zvinokurudzirwa kuti iyo Planck inogara ichishandiswa kutsanangura iyo mass unit kilogram, uye ane hunyanzvi hwepamusoro-level marabhoritari anokurudzirwa kuita zvinoenderana nesainzi basa rekutsvagisa.
Naizvozvo, pa2018 International Conference on Metrology, masayendisiti akavhota kuti abvise zviri pamutemo kirogiramu yepasi rose, uye akachinja Planck constant (symbol h) semwero mutsva wekutsanangura patsva "kg".
Nguva yekutumira: Mar-05-2021