ʻEhia ke kaumaha o ke kilokani? Ua noiʻi nā kānaka ʻepekema i kēia pilikia maʻalahi no nā haneli makahiki.
I ka makahiki 1795, ua hoʻolaha ʻo Farani i ke kānāwai i hoʻopaʻa i ka "gram" ʻo ia hoʻi "ke kaumaha paʻa o ka wai i loko o kahi cube nona ka nui e like me hoʻokahi haneli 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 mea paʻa loa i ka wā e kiʻekiʻe loa ai ka nui o ka wai ma 4°C, no laila ua loli ka wehewehe ʻana o ke kilokani i "ka nui o 1 cubic decimeter o ka wai maʻemaʻe ma 4°C". Ua hana kēia i kahi kilokani platinum kumu maʻemaʻe, ua wehewehe ʻia ke kilokani e like me kona nui, i kapa ʻia ʻo ka kilokani waihona.
Ua hoʻohana ʻia kēia kilogram waihona ma ke ʻano he pae hoʻohālikelike no 90 mau makahiki. I ka makahiki 1889, ua ʻāpono ka ʻAha Kūkākūkā Honua Mua ma ka Metrology i kahi kope platinum-iridium alloy kokoke loa i ka kilogram waihona e like me ke kilogram kumu honua. Ua wehewehe ʻia ke kaumaha o ka "kilogram" e kahi cylinder platinum-iridium alloy (90% platinum, 10% iridium), nona ke kiʻekiʻe a me ke anawaena ma kahi o 39 mm, a ke mālama ʻia nei i loko o kahi hale lua ma waho o Palisa.
Kilokilo kumu honua
Mai ka Au o ka Mālamalama, ua kūpaʻa ke kaiāulu ana i ka hoʻokumu ʻana i kahi ʻōnaehana ana honua. ʻOiai he ala hiki ke hoʻohana i ka mea kino ma ke ʻano he pae ana, no ka mea ua hōʻino maʻalahi ʻia ka mea kino e nā mea i hana ʻia e ke kanaka a i ʻole nā mea pili i ke kaiapuni, e hoʻopilikia ʻia ke kūpaʻa, a ua makemake mau ke kaiāulu ana e haʻalele i kēia ʻano hana i ka wā hikiwawe loa.
Ma hope o ka hoʻohana ʻana o ke kilokani i ka wehewehena kilokani mua o ka honua, aia kahi nīnau e hopohopo nui nei nā metrologists: pehea ka paʻa o kēia wehewehena? E neʻe anei ia i ka hala ʻana o ka manawa?
Pono e ʻōlelo ʻia ua hāpai ʻia kēia nīnau i ka hoʻomaka ʻana o ka wehewehe ʻana o ke kilokani anakahi nuipa. No ka laʻana, i ka wā i wehewehe ʻia ai ke kilokani i ka makahiki 1889, ua hana ka International Bureau of Weights and Measures i 7 mau kaupaona kilokani platinum-iridium alloy, ʻo kekahi o ia mau mea ʻo ka International. Hoʻohana ʻia ke kilokani mua e wehewehe i ke kilokani anakahi nuipa, a ʻo nā kaupaona ʻē aʻe 6 i hana ʻia me ka mea like a me ke kaʻina hana like e hoʻohana ʻia ma ke ʻano he mau pae hoʻohālikelike lua e nānā inā he ʻauwana ma waena o kekahi me kekahi i ka hala ʻana o ka manawa.
I ka manawa like, me ka hoʻomohala ʻana o ka ʻenehana kikoʻī kiʻekiʻe, pono mākou i nā ana paʻa a pololei hoʻi. No laila, ua hāpai ʻia kahi hoʻolālā e wehewehe hou i ke anakahi kumu honua me nā mea mau kino. ʻO ka hoʻohana ʻana i nā mea mau e wehewehe i nā anakahi ana ʻo ia hoʻi e hoʻokō 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 loko o nā makahiki 100 mai 1889 a i 2014, ua loli ke ʻano kūlike o nā kilograma kumu ʻē aʻe a me ke kilograma kumu honua ma kahi o 50 micrograms. Hōʻike kēia he pilikia me ke kūpaʻa o ka pae hoʻohālikelike kino o ka ʻāpana maikaʻi. ʻOiai ke kani liʻiliʻi nei ka loli o 50 micrograms, he hopena nui ia i kekahi mau ʻoihana kiʻekiʻe.
Inā hoʻohana ʻia nā kūpaʻa kino kumu e pani i ka pae hoʻohālikelike kino kilogram, ʻaʻole e hoʻopilikia ʻia ke kūpaʻa o ka ʻāpana nuipa e ka hakahaka a me ka manawa. No laila, i ka makahiki 2005, ua kākau ke Komite Honua no nā Kaumaha a me nā Ana i kahi ʻōnaehana no ka hoʻohana ʻana i nā kūpaʻa kino kumu e wehewehe i kekahi mau ʻāpana kumu o ka ʻōnaehana honua o nā ʻāpana. Manaʻo ʻia e hoʻohana ʻia ke kūpaʻa Planck e wehewehe i ka ʻāpana nuipa kilogram, a paipai ʻia nā keʻena hoʻokolohua pae aupuni kūpono e hana i nā hana noiʻi ʻepekema pili.
No laila, ma ka 2018 International Conference on Metrology, ua koho balota nā kānaka ʻepekema e hoʻopau kūhelu i ke kilokika prototype honua, a ua hoʻololi i ke kūpaʻa Planck (hōʻailona h) ma ke ʻano he kūlana hou e wehewehe hou i ka "kg".
Ka manawa hoʻouna: Malaki-05-2021