Atoms tuaj yeem nce lossis poob lub zog thaum lub tshuab hluav taws xob txav los ntawm qhov siab dua mus rau qis qis ib ncig ntawm cov keeb. Txawm li cas los xij, kev faib cov nucleus ntawm atom yuav tso ntau lub zog ntau dua li lub zog thaum cov hluav taws xob rov qab mus rau qis qis los ntawm qhov chaw siab dua. Lub zog ntawd tuaj yeem siv rau lub hom phiaj puas tsuaj lossis rau lub hom phiaj nyab xeeb thiab tsim khoom. Kev faib cov atom yog hu ua nuclear fission, txheej txheem tshawb pom xyoo 1938; Kev rov ua dua ntawm cov atoms hauv fission hu ua chain reaction. Txawm hais tias coob leej neeg tsis muaj cov cuab yeej los ua qhov no, yog tias koj xav paub txog cov txheej txheem sib cais, ntawm no yog cov ntsiab lus.
Kauj ruam
Ntu 1 ntawm 2: Yooj Yim Atomic Fission
Kauj Ruam 1. Xaiv lub isotope uas raug
Qee lub ntsiab lus lossis lawv cov isotopes dhau los ntawm cov kab mob tawg. Txawm li cas los xij, tsis yog txhua isotopes tau tsim sib npaug raws li lawv qhov yooj yim ntawm kev tshem tawm. Feem ntau siv isotope ntawm uranium, muaj qhov hnyav atomic ntawm 238, suav nrog 92 protons thiab 146 neutrons, tab sis nws cov nucleus nyhav nqus cov neutron yam tsis faib rau hauv cov nuclei me ntawm lwm yam. Ib isotope ntawm uranium uas muaj peb qhov tsawg dua neutrons, 235U, tuaj yeem ua kom yooj yim dua li cov isotopes 238U; Cov isotopes no hu ua cov khoom tawg.
Qee qhov isotopes tuaj yeem muab tshem tawm tau yooj yim heev, yog li nrawm heev uas tsis tuaj yeem tswj tau. Qhov no hu ua spontaneous fission; isotope ntawm plutonium 240Pu yog piv txwv ntawm isotope ntawd, tsis zoo li isotope 239Pu nrog qeeb tus nqi qis dua.
Kauj Ruam 2. Tau txais cov isotopes txaus kom ntseeg tau tias kev sib cais yuav txuas ntxiv tom qab thawj lub atom cais
Qhov no yuav tsum muaj qee yam tsawg ntawm cov khoom siv isotopic yuav tsum tau qhib qhib rau cov tshuaj tiv thaiv fission kom tshwm sim; Tus nqi no hu ua qhov hnyav. Tau txais qhov hnyav tseem ceeb xav tau cov khoom siv rau isotope, txhawm rau ua kom muaj feem ntawm kev tawg.
Qee zaum, nws yog qhov yuav tsum tau nce tus txheeb ze sib faib cov khoom isotope hauv cov qauv kom ntseeg tau tias cov tshuaj tiv thaiv tsis tu ncua tuaj yeem tshwm sim. Qhov no hu ua kev txhawb ntxiv, thiab muaj ntau txoj hauv kev siv los txhawb qhov piv txwv. (Rau cov txheej txheem siv los txhim kho uranium, saib wikiHow Yuav Txhim Kho Uranium li cas.)
Kauj Ruam 3. Tua lub nucleus ntawm cov khoom isotope cais nrog subatomic particles ntau zaus
Ib qho me me subatomic tuaj yeem tsoo atoms 235U, faib nws mus rau ob qhov sib cais ntawm lwm lub hauv paus thiab tso peb lub neutrons. Peb hom subatomic particles feem ntau siv.
- Proton. Cov subatomic hais no muaj qhov hnyav thiab muaj txiaj ntsig zoo. Tus naj npawb ntawm protons hauv ib qho atom txiav txim siab lub hauv paus ntawm atom.
- Neutrons. Cov subatomic hais no muaj qhov hnyav li protons tab sis tsis muaj nqi.
- Alpha hais. Cov particle no yog lub nucleus ntawm lub helium atom, ib feem ntawm cov electrons uas tig ncig nws. Cov khoom no muaj ob lub protons thiab ob lub neutron.
Ntu 2 ntawm 2: Txoj Cai Fission Atomic
Kauj Ruam 1. Tua ib lub atomic nucleus (nucleus) ntawm tib isotope ntawm lwm qhov
Vim tias cov nyom subatomic hais lus nyuaj dhau los, lub zog feem ntau xav tau kom yuam cov khoom tawm ntawm lawv cov atoms. Ib txoj hauv kev ua qhov no yog tua atoms ntawm qhov muab isotope ntawm lwm atoms ntawm tib isotope.
Txoj kev no tau siv los tsim lub foob pob tawg 235Koj poob rau Hiroshima. Riam phom xws li phom nrog cov tub ntxhais uranium, uas tua atoms 235Ua atom 235Lwm tus U, nqa cov khoom siv ntawm qhov nrawm uas nws ua rau cov tso tawm neutrons tsoo lub nucleus ntawm atom 235lwm U thiab rhuav tshem nws. Cov neutron tso tawm thaum lub atom sib cais tuaj yeem hloov pauv tsoo thiab faib cov atom 235lwm U.
Kauj Ruam 2. Nyuaj cov qauv atomic nruj, nqa cov khoom atomic los ze zog ua ke
Qee zaum, cov atoms lwj sai heev kom raug rho tawm haujlwm ib leeg. Hauv qhov no, nqa cov atoms los ze zog ua ke ua rau muaj feem ntawm kev tso tawm subatomic particles tsoo thiab faib lwm cov atoms.
Txoj kev no tau siv los tsim lub foob pob tawg 239Pu poob rau Nagasaki. Kev tawg ib puag ncig puag ncig qhov hnyav ntawm plutonium; thaum tawg, qhov tawg ua rau plutonium huab hwm coj, nqa cov atoms 239Pu mus kom ze kom cov neutron tso tawm yuav txuas mus ntxiv thiab faib cov atoms 239lwm pu.
Kauj Ruam 3. Txaus siab rau cov tshuab hluav taws xob nrog lub teeb ci laser
Nrog kev txhim kho ntawm petawatt laser (1015 watts), tam sim no muaj peev xwm faib cov atoms siv lub teeb ci laser kom ua rau cov electrons zoo nyob hauv cov hlau ntim cov khoom siv hluav taws xob.
- Hauv kev sim xyoo 2000 ntawm Lawrence Livermore Laboratory hauv California, uranium tau qhwv kub thiab muab tso rau hauv tooj liab. Lub plawv dhia ntawm cov duab hluav taws xob laser ntawm 260 joules tsoo lub hnab ntawv thiab vaj tse, ua rau cov khoom siv hluav taws xob zoo siab. Raws li cov hluav taws xob rov qab mus rau lawv qhov qub ib puag ncig, lawv tso tawm lub zog hluav taws xob gamma uas nkag mus rau cov kub thiab tooj liab, tso cov neutrons uas nkag mus rau hauv lub uranium atoms hauv qab txheej kub thiab faib lawv sib nrug. (Ob qho kub thiab tooj liab tau dhau los ua hluav taws xob los ntawm kev sim.)
- Cov kev sim zoo sib xws tau ua tiav ntawm Rutherford Appleton Laboratory hauv tebchaws Askiv siv 50 terawatts (5 x 10)12 watts) laser tsom mus rau phaj tantalum nrog ntau yam khoom siv tom qab nws: potassium, nyiaj, zinc, thiab uranium. Ib feem ntawm atoms ntawm tag nrho cov ntaub ntawv no tau ua tiav sib cais.
Ceeb toom
- Ntxiv rau qee qhov fission ntawm qee cov isotopes uas nrawm heev, kev tawg me me tuaj yeem rhuav tshem cov khoom tawg ua ntej qhov tawg mus txog qhov xav tau ntawm cov tshuaj tiv thaiv.
- Ib yam li lwm yam khoom siv, ua raws cov txheej txheem kev nyab xeeb xav tau, thiab tsis txhob ua ib yam uas zoo li pheej hmoo. Ceev faj.
