Watsawa
Watsawa kalma ce da ake amfani da ita a cikin ilimin kimiyyar lissafi don bayyana nau'ikan tafiyar matakai na zahiri inda aka tilasta wa barbashi motsi ko radiation na wani nau'i, kamar haske ko sauti, su karkata daga madaidaicin yanayin ta hanyar da ba daidai ba (ciki har da barbashi da radiation) matsakaicin da suke wucewa. A cikin amfani na al'ada, wannan kuma ya haɗa da karkatar da hasken haske daga kusurwar da dokar tunani ta annabta.Tunani na radiation da ke fama da tarwatsewa galibi ana kiran su ra'ayoyi masu yaduwa kuma abubuwan da ba a warwatse ba ana kiransu tunani na musamman (kamar madubi). Asalinsu, kalmar ta keɓe ga tarwatsewar haske (komawa aƙalla har zuwa Isaac Newton a ƙarni na 17[1]). Yayin da aka gano wasu abubuwa masu kama da “ray”, an fadada tunanin watsawa gare su, ta yadda William Herschel zai iya yin nuni ga tarwatsawar “hasken zafi” (ba a gane shi a matsayin electromagnetic a yanayi ba) a cikin 1800.[2]. John Tyndall, majagaba a cikin binciken tarwatsa haske, ya lura da alaƙa tsakanin watsawar haske da watsa sauti a cikin 1870s.[3] Kusa da ƙarshen karni na 19, an lura da watsar da hasken cathode (biyoyin lantarki) [4] da X-ray [5] kuma an tattauna su. Tare da gano ƙwayoyin subatomic (misali Ernest Rutherford a cikin 1911[6]) da kuma haɓaka ka'idar ƙididdiga a cikin karni na 20, ma'anar kalmar ta zama mafi girma yayin da aka gane cewa ana iya amfani da tsarin lissafi iri ɗaya da aka yi amfani da shi a watsar haske. ga sauran al'amura da dama.

Watsawa na iya nufin sakamakon karo-karo-barbashi tsakanin kwayoyin halitta, atom, electrons, photons da sauran barbashi. Misalai sun haɗa da: raye-rayen sararin samaniya a cikin sararin sama na duniya; haduwar barbashi a cikin masu kara kuzari; watsawar lantarki ta atomatik atom a cikin fitilu masu kyalli; da neutron da ke warwatse a cikin injinan nukiliya.[7]

Nau'in rashin daidaituwa wanda zai iya haifar da watsawa, wani lokacin da aka sani da masu watsawa ko cibiyoyin watsawa, suna da yawa don lissafin, amma ƙaramin samfurin ya haɗa da barbashi, kumfa, ɗigon ruwa, haɓakar yawa a cikin ruwaye, crystallites a cikin polycrystalline solids, lahani a cikin daskararrun monocrystalline. , rashin ƙarfi na sama, sel a cikin kwayoyin halitta, da zaren yadi a cikin tufafi. Tasirin irin waɗannan siffofi akan hanyar kusan kowane nau'in igiyar ruwa mai yaɗa ko motsi mai motsi ana iya bayyana shi a cikin tsarin ka'idar watsawa.