Kuwo wonke umlando, abantu baye bezwa ukusithakasela okujulile isibhakabhaka, hhayi nje kuphela phakathi nobusuku bokucabanga obuvusa imizwa ekhona, kodwa naphakathi namahora okukhanya kwasemini, lapho sibonisa inqwaba yemibala egqamile. Ngesinye isikhathi ekuphileni kwethu, sonke siye sazibuza ukuthi kungani isibhakabhaka sibonakala siluhlaza okwesibhakabhaka noma kungani sishintsha amathoni awolintshi nabomvu ngesikhathi sokushona kwelanga. Lo mbuzo waqale waxazululwa nguLord Rayleigh, owaziwa nangokuthi uJohn William Strutt, isazi sezibalo esathola lokhu ngasekupheleni kwekhulu le-19.
Kulesi sihloko sizochaza kuwe Umphumela we-Rayleigh, izici zayo nokuthi kungani isibhakabhaka siluhlaza okwesibhakabhaka.
Umphumela we-Rayleigh
ILanga likhipha imisebe eminingi kagesi, okuhlanganisa ukukhanya okubonakalayo, okuvame ukwaziwa ngokuthi ukukhanya okumhlophe. Kuyathakazelisa ukuthi ukukhanya okumhlophe empeleni kuyinhlanganisela yayo yonke imibala yothingo, kanti i-violet iwubude obufushane kakhulu be-waveleng kanye nobomvu bubude kakhulu. Njengoba Ukukhanya kwelanga kuhamba emkhathini, kuhlangana nezinto ezihlukahlukene njengamagesi, izinhlayiya eziqinile nama-molecule amanzi.. Uma lezi zinhlayiya zizincane kunengxenye yeshumi ye-micrometer, zibangela ukusakazeka kokukhanya okumhlophe kuzo zonke izinhlangothi, ngokugcizelela kakhulu ukukhanya okuluhlaza okwesibhakabhaka.
Lokhu kukhethwa kokukhanya okuluhlaza okwesibhakabhaka kungachazwa yi-coefficient yokuhlakazwa, ebalwa kusetshenziswa ifomula 1/λ4, lapho u-λ umele ubude begagasi. Njengoba ukukhanya oku-violet nokuluhlaza kunobude obufushane kunawo wonke ku-spectrum ebonakalayo, kukhiqiza isilinganiso esiphezulu kakhulu lapho kufakwa esikhundleni sefomula, ethi . Lesi simo sivame ukubizwa ngokuthi i-Rayleigh scattering.
Ngenxa yalokho, imisebe ehlakazekile ihlangana nezinhlayiya zegesi ezisebenza njengendawo ekhanyayo, ezenza ziphinde zigobe futhi zikhulise amandla azo.
Kungani isibhakabhaka siluhlaza?
Uma ucabangela ulwazi olushiwo ngenhla, umuntu angase alindele ukuthi isibhakabhaka sibonakale sinsomi esikhundleni sokuba sibe luhlaza okwesibhakabhaka ngenxa yobude baso obufushane. Nokho, lokhu akunjalo ngoba iso lomuntu alizwani kakhulu nombala we-violet. Ngaphandle kwalokho, Ukukhanya okubonakalayo empeleni kuqukethe ingxenye ephezulu yemisebe ye-wavelength eluhlaza okwesibhakabhaka kune-violet.
Ezimeni lapho izinhlayiya zidlula ubude be-waveleng ngosayizi, ukuhlakazeka okuhlukile akwenzeki. Esikhundleni salokho, zonke izingxenye zokukhanya okumhlophe zihlakazeka ngokulinganayo. Lesi senzakalo sichaza ukubukeka okumhlophe kwamafu, njengoba amaconsi amanzi awakhayo edlula ingxenye yeshumi ye-micrometer ububanzi. Nokho, lapho la maconsi amanzi eminyene, ukukhanya angeke kudlule kubo, okuholela ekubonakaleni okumpunga okuhlotshaniswa nekhava yamafu ebanzi.
Nokho, kumelwe kuqashelwe ukuthi isibhakabhaka asiwugcini umbala oluhlaza njalo. Ngenxa yalokho, isenzakalo sokuhlakazeka kweRayleigh akuchazi ngokugcwele ukuba khona kwemibala ehlukahlukene ebomvu ngesikhathi sokuphuma nokushona kwelanga. Nokho, kunencazelo yaleli qiniso.
Njengoba iLanga lishona futhi lingena esigabeni sokuhwalala, ukuma kwalo emkhathizwe kubangela ukukhanya kuhambe ibanga elide ukuze kufinyelele kithi, kungabe kusaba yi-perpendicular. Lolu shintsho lwe-engeli luholela ezenzakalweni eziphansi, okubangela ukukhanya okuluhlaza okwesibhakabhaka kuhlakazeke ngaphambi kokuba kufinyelele emehlweni ethu. Kunalokho, . Kubalulekile ukuqaphela ukuthi ukuhlakazeka kweRayleigh kuyaqhubeka ukwenzeka, kodwa endaweni ehlukile emkhathini kunalapho iLanga lisezingeni eliphezulu.
historia
Kuwo wonke umlando, isibhakabhaka siye sakhanga ukunaka kwethu kokubili emini nasebusuku. Isebenze njengendwangu yokuzulazula emcabangweni wethu. Ngokwemvelo, ilukuluku kanye nocwaningo lwesayensi akuzange kukhishwe kulokhu kuthakasela. Njengezinye izenzakalo zansuku zonke, njengokushintsha kombala wamaqabunga noma umsuka wemvula, abacwaningi baye bazama ukuthola izimfihlakalo zesibhakabhaka. Kunokuba inciphise ukukhanga kwayo okungaqondakali, okutholakele kuye kwajulisa ukuqonda kwethu nokuthakasela kwethu.
Ngesikhathi sokuhlolwa kwakhe kwe-infrared ngo-1869, uRayleigh wathola ukutholakala okungalindelekile: ukukhanya okuhlakazwe izinhlayiya ezincane kwakunombala oluhlaza okwesibhakabhaka ocashile. Lokhu kwamholela ekubeni acabange ukuthi ukusakazeka okufanayo kokukhanya kwelanga yikona okubangele umbala oluhlaza wesibhakabhaka. Nokho, akakwazanga ukuchaza ngokugcwele ukuthi kungani kukhethwa ukukhanya okuluhlaza okwesibhakabhaka noma ukuthi kungani umbala wesibhakabhaka wawushube kangaka, ekhipha uthuli olusemkhathini njengokuwukuphela kwencazelo.
Umsebenzi wakhe oyinhloko ophathelene nombala nokuhlukanisa ukukhanya okuvela esibhakabhakeni wanyatheliswa ngo-1871. Umgomo wakhe wawuwukulinganisa umphumela weTyndall emaconsini amanzi ngokulinganisa ukuba khona kwezinhlayiya ezincane kanye nezinkomba zazo ezibukwayo. Ukwakhela phezu kobufakazi bukaJames Clerk Maxwell bangaphambili bemvelo yokukhanya kwe-electromagnetic, uRayleigh wabonisa ngo-1881 ukuthi ama-equations akhe alandela ku-electromagnetism. Enweba lokho akutholile ngo-1899, wanweba isicelo kuma-molecule ngamanye, esikhundleni samagama ahlobene namavolumu ezinhlayiya kanye nezinkomba zokuphinda aphendule ngemibandela ye-molecular polarizability.
Ukuhlakazeka ezintweni ezimbotshana
Izinto ezisetshenziswayo ezinama-porous zinekhono lokubonisa ukuhlakazeka kohlobo lwe-Rayleigh, okulandela iphethini yokuhlakazeka engu-λ-4. Lesi simo sibonakala ikakhulukazi ezintweni ezisetshenziswa yi-nanoporous, lapho kunomehluko omkhulu kunkomba ye-refractive phakathi kwezimbotshana nezingxenye eziqinile ze-alumina e-sintered. Ngenxa yalokho, i- ukusabalalisa ukukhanya iba namandla ngendlela emangalisayo, iyenze ishintshe indlela cishe njalo ngama-micrometer amahlanu.
Lokhu kuziphatha kokuhlakazeka okuphawulekayo kubangelwa ukwakheka kwe-nanoporous okuyingqayizivele okuzuzwe ngenqubo yokucwilisa, okubandakanya ukusetshenziswa kwempushana ye-alumina monodispersive ukudala ukusatshalaliswa okuncane kosayizi wembotshana, ngokuvamile ebalelwa ku-70 nm.
