Ehia ke kaumaha o ke kilo? Ua ʻimi nā kānaka ʻepekema i kēia pilikia maʻalahi no nā haneli mau makahiki.
I ka makahiki 1795, ua hoʻolaha ʻo Farani i ke kānāwai e ʻōlelo ana i ka "gram" ʻo ia "ke kaumaha piha o ka wai i loko o kahi pahu kupa nona ka nui i like me ka hapahaneri o ka mika ma ka mahana i ka wā e heheʻe ai ka hau (ʻo ia hoʻi, 0°C). I ka makahiki 1799, ua ʻike nā kānaka ʻepekema ʻo ka nui o ka wai ka paʻa loa ke kiʻekiʻe loa ka mānoanoa o ka wai ma 4°C, no laila ua hoʻololi ʻia ka wehewehe ʻana o ke kilo i "ka nui o 1 cubic decimeter o ka wai maʻemaʻe ma 4°C. ”. Ua hoʻopuka kēia i kahi kilokani mua platinum maʻemaʻe, ua wehewehe ʻia ka kilokani e like me kona nuipaʻa, i kapa ʻia ʻo ka waihona kilokilo.
Ua hoʻohana ʻia kēia kilokika waihona ma ke ʻano he benchmark no 90 mau makahiki. I ka makahiki 1889, ua ʻae ʻia e ka First International Conference on Metrology i kahi kope o ka platinum-iridium alloy kokoke loa i ka kilo kilokani e like me ke kilokani kumu honua. ʻO ke kaumaha o ka "kilogram" i wehewehe ʻia e ka platinum-iridium alloy (90% platinum, 10% iridium) cylinder, aia ma kahi o 39 mm ke kiʻekiʻe a me ke anawaena, a ke mālama ʻia nei i loko o kahi haʻahaʻa ma waho o Paris.
Kilokika kumu honua
Mai ka makahiki o ka naauao, ua paa ka poe nana ana i ka hookumu ana i ke ao holookoa. ʻOiai he ala kūpono ia e hoʻohana ai i ka mea kino e like me ke ana ʻana, no ka mea ua maʻalahi ka mea kino i ka hana ʻia e ke kanaka a i ʻole nā mea kaiapuni, e hoʻopilikia ʻia ke kūpaʻa, a ua makemake mau ke kaiāulu ana e haʻalele koke i kēia ʻano hana. e like me ka hiki.
Ma hope o ka ʻae ʻana o ka kilo i ka wehewehena kilokani kumu honua, aia kahi nīnau e hopohopo nui ai ka poʻe metrologists: pehea ka paʻa o kēia wehewehe? E nee ana paha i ka manawa?
Pono e ʻōlelo ʻia ua hāpai ʻia kēia nīnau i ka hoʻomaka ʻana o ka wehewehe ʻana o ka kilo kilo. No ka laʻana, i ka wā i wehewehe ʻia ai ka kilo i ka makahiki 1889, ua hana ka International Bureau of Weights and Measures i 7 platinum-iridium alloy kilo paona, ʻo kekahi o ia ka International Ua hoʻohana ʻia ka kilokani kumu e wehewehe i ka nuipa kilo kilo, a ʻo nā mea kaupaona 6 ʻē aʻe. i hana ʻia me ka mea like a ua hoʻohana ʻia ke kaʻina hana like me nā pae kiʻekiʻe kiʻekiʻe e nānā inā he neʻe ka manawa ma waena o kekahi.
I ka manawa like, me ka hoʻomohala ʻana i ka ʻenehana kiʻekiʻe, pono mākou i nā ana paʻa a pololei. No laila, ua manaʻo ʻia kahi hoʻolālā e wehewehe hou i ka ʻāpana kumu honua me nā mea mau kino. ʻO ka hoʻohana ʻana i nā mea maʻamau e wehewehe i nā ʻāpana ana ʻo ia ka mea e hoʻokō ai kēia mau wehewehe i nā pono o ka hanauna hou o nā ʻike ʻepekema.
Wahi a ka ʻikepili kūhelu o ka International Bureau of Weights and Measures, i nā makahiki 100 mai 1889 a i 2014, ua hoʻololi ʻia ke kūlike o ka maikaʻi o nā kilokani kumu ʻē aʻe a me ka kilokani kumu honua ma kahi o 50 micrograms. Hōʻike kēia i ka pilikia me ka paʻa o ka pae kino o ka ʻāpana maikaʻi. ʻOiai ke kani liʻiliʻi ka hoʻololi o 50 micrograms, he hopena nui ia i kekahi mau ʻoihana kiʻekiʻe.
Inā hoʻohana ʻia nā mea hoʻomau kino maʻamau e pani i ka pae kino kilokilo, ʻaʻole e hoʻopilikia ʻia ka paʻa o ka ʻāpana nui e ka lewa a me ka manawa. No laila, i ka makahiki 2005, ua hoʻolālā ke Kōmike Kūʻokoʻa no nā Weights and Measures i kahi papa hana no ka hoʻohana ʻana i nā mea maʻamau kino e wehewehe i kekahi mau ʻāpana kumu o ka International System of Units. Manaʻo ʻia e hoʻohana ʻia ka Planck mau no ka wehewehe ʻana i ka kilo kilokani nui, a paipai ʻia nā keʻena hana hoʻonaʻauao kūlana ʻāina e hana i nā hana noiʻi ʻepekema pili.
No laila, ma ka 2018 International Conference on Metrology, ua koho nā kānaka ʻepekema i ka decommission o ka honua prototype kilokani, a hoʻololi i ka Planck mau (hōʻailona h) ma ke ʻano he maʻamau hou e wehewehe hou i ka "kg".
Ka manawa hoʻouna: Mar-05-2021