ˈæz ˈaɪ ˈsɛd bɪˈfɔr ˈkʰɛməstɹɪ ˈɪz, ˈlaɪk ˈmɛnɪ ˈæˌspɛkts əv ˈjɔr ˈoʊn ˈlaɪf, ˈɔɫ əˈbaʊt ə ˈsɝtʃ ˈfɔr stəˈbɪləɾɪ.
ˈlæst ˈwiːk ˈwiː ˈtʰɔkt əˈbaʊt ˌɹeɪɾiːoˈæktɪv dɪˈkʰeɪ
ənd ˈhaʊ əˈtʰɑmɪk ˈnuːkliːˌaɪ ˈɡɛt ˈɹɪd əv ˈvɛriːəs ˈpʰɑrɾɪkəɫz ˈɪn ˈɔrɾɚ ˈtʰuː bɪˈkʰʌm ˈmɔr ˈsteɪbəɫ.
ˈbʌt ˈwɑt ˈɪz ˈðɪs ɪˈluːsɪv stəˈbɪləɾɪ ˈðæt ˈɔɫ ˈθɪŋz ˈsiːm ˈtʰuː ˈbiː ˈstɹaɪvɪŋ ˈfɔr ɪɡˈzæktlɪ?
ˈɪn ˈnuːkliːɚ ˈkʰɛməstɹɪ ˈɪt ˈsɪmplɪ ˈhæs tə ˈduː ˈwɪθ ˈkʰiːpɪŋ ðə ˈnuːkliːəs təˈɡɛðɚ.
ˈɪf ðə ˈnuːkliːəs ˈɪz ˈɡoʊɪŋ ˈtʰuː ˈbɹeɪk əˈpʰɑrt, ˈðɛn ˈðæts ˈnɑt ˈɡoʊɪŋ ˈtʰuː ˈbiː ˈsʌmˌθɪŋ ˈðæt ˈlæsts ˈvɛrɪ ˈlɔŋ.
stəˈbɪləɾɪ ˈɹiːəlɪ, ˈɪz ˈkʰaɪnd əv ˈdʒʌst ə ˈweɪ əv ˈseɪɪŋ, ˈɪt kən ɪɡˈzɪst.
ənd ðiː əˈmaʊnt əv ˈɛnɚdʒɪ, ˈðæt ˈhoʊɫdz ˈiːtʃ ˈpɹoʊˌtɑn ˈɔr ˈnuːˌtɹɑn ˈɪn ən ˈæɾəmz ˈnuːkliːəs,
ˈɪz ðə ˈseɪm əˈmaʊnt ˈðæts ɹɪˈliːst ˈwɛn ˈɪts ɹɪˈmuːvd.
ˈðɪs ˈɪz ˈnoʊn ˈæz ˈbaɪndɪŋ ˈɛnɚdʒɪ ənd ˈɪts ˈwʌn əv ðə ˌfʌndəˈmɛntɫ̩ ˈpɹɪnsəpəɫz əv ˈnuːkliːɚ ˈkʰɛməstɹɪ.
ˈɪts ˈæktʃəwəlɪ ˈwɑt ˈwiː ˈmiːn ˈwɛn ˈwiː ˈtʰɔk əˈbaʊt ˈnuːkliːɚ ˈɛnɚdʒɪ.
ˈnaʊ ˈaɪm ˈnɑt ˈɡoʊɪŋ ˈtʰuː ˈlaɪ ˈtʰuː ˈjuː, ˈnuːkliːɚ ˈkʰɛməstɹɪ ˈɪz ˈtʰɛrəblɪ ˈkʰɑmpləˌkeɪɾəd,
ˈbʌt ˈwiː ˈhæv ə ˈweɪ əv ˌʌndɚˈstændɪŋ ˈɪt ˈðæt, ˈwaɪəɫ ˈnɑt ɪɡˈzæktlɪ ˈsɪmpəɫ, ˈɪz ˈwʌn ˈaɪm ˈʃʊr ˈjuːv ˈhɝd əv.
ðə ˈbaɪndɪŋ ˈɛnɚdʒɪ əv ən ˈæɾəm ˈɪz ˈkʰæɫkjəˌleɪɾəd ˈwɪθ ðə ˈfɔrmjələ ˈiː = /mctwo/.
ˈpɹɑbəblɪ ðə ˈmoʊst ˈfeɪməs ɪˈkweɪʒən ˈɪn ðə ˈwɝɫd,
ənd ˈsɪns ˈɪt ˈwəz ˈfɝst ˈhɪt əˈpʰɔn ˈbaɪ ə ˈjʌŋ ˈpʰæʔn̩t ˈklɝk ˈɪn naɪnˈtʰiːn ˈoʊ ˈfaɪv ˈɪt ˈhæz bɪˈkʰʌm səˈnɑnəməs ˈwɪθ ˌsaɪənˈtʰɪfɪk ˈdʒiːnjəs.
ˈpʰɑrt əv ˈwaɪ ˈɪts ˈsoʊ ˈfeɪməs, ˈaɪ ˈlaɪk ˈtʰuː ˈθɪŋk, ˈɪz bɪˈkʰɔz ðə ˈlɑdʒɪk bɪˈhaɪnd ˈɪt ˈɪz ˈsoʊ ˈɛlɪɡəntlɪ ˈsɪmpəɫ,
ənd ˈjɛt ˈtʰoʊɾɫ̩ɪ ˈkʰaʊntɚ ɪnˈtʰuːəɾɪv, ˈbʌt ˈɪts ˈpɹɑbəblɪ ˈɔɫˌsoʊ ˈfeɪməs bɪˈkʰɔz ˈɪts ɪmˈpʰɔrʔn̩t.
ˈɪt ɪkˈspleɪnz ˈwʌn əv ðə ˈmoʊst ˈpʰaʊɚfəɫ ˈsɔrsəz əv ˈɛnɚdʒɪ ˈnoʊn ˈtʰuː hjuːˈmænəɾɪ.
[ˈθiːm ˈmjuːzɪk]
ˈiː = /mctwo/ ˈɪz ˈfɔrməlɪ ˈnoʊn ˈæz ðə ˈmæs-ˈɛnɚdʒɪ ɪˈkwɪvələns ˈfɔrmjələ
ənd ˈɪt ˈsteɪts ˈðæt ˈmæs ˈɪz ˌɪntɚˈtʃeɪndʒəbəɫ ˈwɪθ ˈɛnɚdʒɪ.
oˈkʰeɪ, ˈðɛr ˈɪz ə ˈlɑt ˈðɛr, ˈɪn ˈwɑt ˈaɪ ˈdʒʌst ˈsɛd.
ˈtʰuː ˈtʰiːz ˈɪt əˈpʰɑrt kənˈsɪɾɚ ðə ˈnuːkliːəs əv ən ˈæɾəm əv ˈɑksɪdʒən: ˈeɪt ˈpɹoʊˌtɑnz ənd ˈeɪt ˈnuːˌtɹɑnz.
kəˈlɛktɪvlɪ, ˈbaɪ ðə ˈweɪ, ˈðiːz ˈpʰɑrɾɪkəɫz ˈɑr ˈnoʊn ˈæz ˈnuːkliːˌɑnz.
ˈɪf ˈjuː ˈwɝ ˈtʰuː ˈæd ˈʌp ˈɔɫ ðiː ˌɪndəˈvɪdʒəwəɫ ˈmæsəz əv ˈɔɫ ˌsɪkˈstiːn ˈnuːkliːˌɑnz ˈsɛpɚɹətlɪ
ənd ˈðɛn kəmˈpʰɛr ˈðæt ˈtʰuː ðə ˈtʰoʊɾɫ̩ ˈmæs əv ən ˈæktʃəwəɫ ˈɑksɪdʒən ˈnuːkliːəs,
ˈjuːd ˈfaɪnd ˈðæt ˈðɛrz ə ˈdɪfɹəns bɪˈtwiːn ðə ˈtʰuː.
spɪˈsɪfɪklɪ ðə ˈmæs əv ðə ˈnuːkliːəs, ɪɡˈzæktlɪ ˌfɪfˈtʰiːn əˈtʰɑmɪk ˈmæs ˈjuːnəts,
ˈɪz ˈloʊɚ ˈðæn ðə ˈmæs əv ˈɪts ˌɪndəˈvɪdʒəwəɫ ˈnuːkliːˌɑnz ˈpʰʊt təˈɡɛðɚ, ˈɪn ˈðɪs ˈkʰeɪs ˌsɪkˈstiːn /amu's/.
ˈðæt ˈmæs ˈwɛnt ˈsʌmˌwɛr.
ˈðæt "ˈmɪsɪŋ ˈmæs" ˈɪn ðə ˈnuːkliːəs, ˈnoʊn ˈæz ˈɪts ˈmæs ˈdiːˌfɛkt, ˈɪz ˈæktʃəwəlɪ ˈpɹɛzn̩t ˈɪn ðə ˈfɔrm əv ˈɛnɚdʒɪ.
ˈɪts ðiː ˈɛnɚdʒɪ ˈðæt ˈhoʊɫdz ðə ˈnuːkliːˌɑnz təˈɡɛðɚ,
ˈsoʊ ˈfɔr ɪɡˈzæmpəɫ ðə ˈmæs ˈdiːˌfɛkt ˈfɔr ən ˈɑksɪdʒən ˈæɾəm ˈɪz ˈnɛɡəɾɪv ˈtʰuː ˈɛks ˈtʰɛn ˈkʰɪləˌɡɹæmz.
ˈtʰuː ˈfaɪnd ˈaʊt ˈhaʊ ˈmʌtʃ ˈbaɪndɪŋ ˈɛnɚdʒɪ ˈðæt ˈmɪsɪŋ ˈmæs əˈmaʊnts ˈtʰuː, ˈjuː kən ˈjuːz ˈɪt ˈæz ðə 'ˈɛm' ˈɪn ˈaɪnstaɪnz ˈfɔrmjələ.
ˈðɪs ɪnˈdʒiːnjəs ˈlɪɾɫ̩ ɪˈkweɪʒən ɹɪˈleɪts ˈmæs ənd ˈɛnɚdʒɪ ˈbaɪ ə ˈsɪmpəɫ pɹəˌpɔrʃəˈnæləɾɪ ˈkʰɑnstənt,
ənd ˈθæŋks ˈtʰuː ˈaɪnˌstaɪn ˈwiː ˈnoʊ ˈðæt ˈkʰɑnstənt ˈɪz ðə ˈskwɛr əv ðə ˈspiːd əv ˈlaɪt, ˈɔr /ctwo/.
ˈsɑɫv ˈfɔr 'ˈiː' ənd ˈjuː ˈfaɪnd ˈðæt ðə ˈbaɪndɪŋ ˈɛnɚdʒɪ ˈɪn ˈðæt ˈɑksɪdʒən ˈnuːkliːəs ˈɪz ˈtʰuː ˈɛks ˈtʰɛn ˈdʒuːɫz,
ˈwɪθ ðə ˈnɛɡəɾɪv ˈsaɪn ˈɪndəˌkeɪɾɪŋ ˈðæt ðiː ˈɛnɚdʒɪ ˈɪz ˈbiːɪŋ ɹɪˈliːst.
ˈnaʊ əv ˈkʰɔrs ˈtʰuː ˈɛks ˈtʰɛn ˈɪz ə ˈvɛrɪ ˈsmɔɫ ˈnʌmbɚ.
ˈðæt ˈmaɪt sɚˈpɹaɪz ˈjuː, ˈbʌt ˈhoʊɫd ðə ˈfoʊn, ˈðæt ˈɪz ˈdʒʌst ˈfɔr ˈwʌn ˈsɪŋɡəɫ ˈnuːkliːəs.
ˈɪf ˈwiː ˈmʌɫtəˌplaɪ ˈðæt ˈbaɪ ˌævəˈɡɑdɹoz ˈnʌmbɚ ˈtʰuː ˈfaɪnd ðiː ˈɛnɚdʒɪ ˈtʃeɪndʒ ˈfɔr ə ˈhoʊɫ ˈmoʊɫ əv ˈɑksɪdʒən ˈnuːkliːˌaɪ,
ə ˈmɪr ˌsɪkˈstiːn ˈɡɹæmz əv ˈɑksɪdʒən, ˈwiː ˈɡɛt ən əˈmeɪzɪŋ ˈwʌn ˈɛks ˈtʰɛn ˈdʒuːɫz əv ˈɛnɚdʒɪ.
ˈtʰuː pɹəˈduːs ˈðæt ˈɛnɚdʒɪ ˈwɪθ ˈkʰoʊɫ, ˈjuː wəd ˈhæf tə ˈbɝn ˈfɔr ˈhʌndɹəd ˈtwɛntɪ ˈθaʊzənd ˈkʰɪləˌɡɹæmz, ˈfɔr ˈhʌndɹəd ˈtwɛntɪ ˈmɛtɹɪk ˈtʰʌnz əv ˈkʰoʊɫ.
ˈðæt ˈɛnɚdʒɪ ˈɪz ˈwɑt ˈwiː ˈmiːn ˈwɛn ˈwiː ˈtʰɔk əˈbaʊt ˈnuːkliːɚ ˈɛnɚdʒɪ,
ðə ˈbaɪndɪŋ ˈɛnɚdʒɪ ˈðæts ɹɪˈliːst ˈwɛn ə ˈnuːkliːˌɑn ˈɪz ɹɪˈmuːvd fɹəm ˈɪts ˈnuːkliːəs.
ˈnaʊ, ˈtʰuː dɪsˈlɑdʒ ˈwʌn əv ˈðoʊz ˈnuːkliːˌɑnz ənd ˌʌnˈliːʃ ˈðæt ˈɛnɚdʒɪ ˈðɛr ˈɑr ˈtʰuː ˈdʒɛnɹəɫ
ˈtʰaɪps əv ˈnuːkliːɚ ɹiːˈækʃənz: ˈfɪʃn̩ ənd ˈfjuːʒn̩.
ˈfɪʃn̩ əˈkʰɝz ˈwɛn ə ˈlɑrdʒ ˈnuːkliːəs ˈsplɪts ˈɪntuː ˈtʰuː ˈlaɪɾɚ ˈwʌnz.
ˈfjuːʒn̩ ˈɪz ðiː ˈɑpəzət ˈwɛn ˈtʰuː ˈlaɪt ˈnuːkliːˌaɪ ˈdʒɔɪn təˈɡɛðɚ ˈtʰuː ˈfɔrm ə ˈhɛviːɚ ˈwʌn.
ˈɪn ˈboʊθ ˈkʰeɪsəz ðə ˈpɹɑˌdʌkts əv ðə ɹiːˈækʃənz ˈɑr ˈmɔr ˈsteɪbəɫ ˈðæn ðə ˈstɑrɾɪŋ məˈtʰɪriːəɫz,
ənd ˈðɪs ˈɪz, ˈæz ˈɔɫˌweɪz, ˈwɑt ˈdɹaɪvz ðə ɹiːˈækʃən.
ˈðɪs ˈɪz ə ˈɡɹæf əv ðə ˈbaɪndɪŋ ˈɛnɚdʒiːz əv ˈvɛriːəs ˈɛləmənts kəmˈpʰɛrd ˈtʰuː ˈðɛr ˈmæs ˈnʌmbɚz.
ˈɛləmənts ˈwɪθ ˈvɛrɪ ˈhaɪ ˈbaɪndɪŋ ˈɛnɚdʒiːz ˈsʌtʃ ˈæz ˈaɪɚn-ˈfɪftiː-ˈsɪks ˈɑr ˈvɛrɪ ˈsteɪbəɫ ənd ˈɹɛrlɪ ˌʌndɚˈɡoʊ ˈnuːkliːɚ ɹiːˈækʃənz.
ˈbʌt ˈɛləmənts ˈwɪθ ˈloʊɚ ˈbaɪndɪŋ ˈɛnɚdʒiːz kən ɹiːˈækt ˈmʌtʃ ˈmɔr ˈɹɛɾəlɪ.
ˈɪf ðə ˈnuːkliːəs ˈɪz ˈhɛviːɚ ˈðæn ˈaɪɚn-ˈfɪftiː-ˈsɪks ˈɪt ˈwɪɫ ˈtʰɛnd ˈtʰuː ˈbɹeɪk ˈɪntuː ˈtʰuː ˈɔr ˈmɔr ˈsmɔlɚ ˈnuːkliːˌaɪ; ə ˈfɪʃn̩ ɹiːˈækʃən.
ˈɪf ˈɪts ˈlaɪɾɚ ˈðæn ˈaɪɚn-ˈfɪftiː-ˈsɪks ˈɪt ˈwɪɫ ˈmɔr ˈlaɪklɪ pɑrˈtʰɪsəˌpeɪt ˈɪn ə ˈfjuːʒn̩ ɹiːˈækʃən,
ˈdʒɔɪnɪŋ ˈtʰuː ˈnuːkliːˌaɪ təˈɡɛðɚ ˈtʰuː ˈfɔrm ə ˈhɛviːɚ ˈwʌn.
ˈbʌt ðə ˈmoʊst ɪmˈpʰɔrʔn̩t ˈθɪŋ ˈtʰuː ˈnoʊɾəs ˈhɪr ˈɪz ˈðæt
ˈwɪθ ˈboʊθ ˈfɪʃn̩ ənd ˈfjuːʒn̩ stəˈbɪləɾɪ ɪnˈkɹiːsəz ˈæz ə ɹɪˈzʌɫt əv ðə ɹiːˈækʃən.
ˈfɪʃn̩ ˈɪz ðə ˈtʰaɪp əv ɹiːˈækʃən ˈðæt ˈwiː ˈjuːz ˈmɔr ˈɔfən
bɪˈkʰɔz ˈɪts ðə ˈwʌn ˈðæt ˈwɪr ˈbɛɾɚ ət ɪˈnɪʃiːˌeɪɾɪŋ ənd kənˈtɹoʊlɪŋ, ət ˈliːst ˈsoʊ ˈfɑr.
ənd ˈwɛðɚ ˈɪts ˈjuːzd ˈɪn ˈpʰaʊɚ ˈplænts ˈɔr ˈbɑmz, ðə ˈmoʊst ˈkʰɑmən ˈfjuːəɫ ˈfɔr ˈfɪʃn̩ ˈɪz jʊˈɹeɪniːəm-ˈtʰuː ˈhʌndɹəd ˈθɝɾiː-ˈfaɪv.
ˈðɛr ˈɑr ˈsɛvɚɹəɫ ˈweɪz ˈðæt ˈɪt kən ɹiːˈækt,
ˈbʌt ðə ɹiːˈækʃən ˈɪz ˈɔɫˌmoʊst ˈɔɫˌweɪz ˈtɹɪɡɚd ˈbaɪ ˈhɪɾɪŋ jʊˈɹeɪniːəm ˈwɪθ ˈnuːˌtɹɑnz fɹəm əˈnʌðɚ ˈsɔrs.
ˈwɛn ˈðæt ˈhæpənz ðə jʊˈɹeɪniːəm ˈsplɪts ˈɪntuː ˈsmɔlɚ ˈæɾəmz.
ˈwʌn ˈsʌtʃ ɹiːˈækʃən pɹəˈduːsəz ˈkɹɪpˌtɑn-ˈnaɪntiː-ˈtʰuː, ˈjɛs ˈkɹɪpˌtɑn ˈɪz ə ˈɹiːəɫ ˈθɪŋ,
əˈlɔŋ ˈwɪθ ˈbɛriːəm-ˈwʌn ˈhʌndɹəd ˈfɔrɾiː-ˈwʌn, ˈθɹiː ˈfɹiː ˈnuːˌtɹɑnz ənd ˈlɑts əv ˈɛnɚdʒɪ.
ˈðɪs ˈɛnɚdʒɪ ˈɪz ɹɪˈliːst ˈmeɪnlɪ ˈæz ðə kəˈnɛɾɪk ˈɛnɚdʒɪ əv ðiː ɪˈskeɪpɪŋ ˈpʰɑrɾɪkəɫz,
ˈwɪtʃ ˈɪz ɪˈmiːɾiːətlɪ tɹænsˈfɝd ˈtʰuː ðə sɚˈɹaʊndɪŋz ˈæz ˈhiːt.
ˈsʌm ˈɛnɚdʒɪ ˈɪz ˈɔɫˌsoʊ ɹɪˈliːst ˈɪn ðə ˈfɔrm əv ɪˈlɛktɹo-mæɡˈnɛɾɪk ˌɹeɪɾiːˈeɪʃən ˈsʌtʃ ˈæz
ˈvɪzəbəɫ ˈlaɪt, ˈɛksˌɹeɪz, ənd ˈɡæmə ˌɹeɪɾiːˈeɪʃən.
ˈnuːkliːɚ ˈpʰaʊɚ ˈplænts ˈjuːz ðiː ˈɛnɚdʒɪ ɹɪˈliːst ˈbaɪ ˈðiːz ɹiːˈækʃənz ˈtʰuː kənˈvɝt ˈwɔɾɚ ˈtʰuː ˈstiːm,
ˈwɪtʃ ˈðɛn ˈɪz ˈpʰæst ˈθɹuː ˈtʰɝbənz ˈspɪnɪŋ ə ˈdʒɛnɚˌɹeɪɾɚ, ˈpʰaʊɚɹɪŋ ˈsɪɾiːz ənd ˈstʌf.
bɪˈkʰɔz əv ðiː ɪˈnɔrməs əˈmaʊnts əv ˈɛnɚdʒɪ ˈðiːz ɹiːˈækʃənz kən ɹɪˈliːs,
ˈnuːkliːɚ ˈpʰaʊɚ ˈplænts kən pəˈtʰɛnʃəlɪ pɹəˈduːs ˈlɑts əv ɪˌlɛkˈtɹɪsəɾɪ,
ˈbʌt ˈðɛrz ˈɔɫˌsoʊ, ˈaɪ ˈθɪŋk ˈjuː ˈmeɪ ˈhæv ˈhɝd, ˈsʌm ˈsɪriːəs ˈdɹɔ ˈbæks.
ˈfɔr ˈwʌn ˈθɪŋ, ˈæz ˈjuː ˈnoʊ, ˈæɾəmz ˈɹɛrlɪ ɪɡˈzɪst ˈɪn ˌaɪsəˈleɪʃən.
ˈwiː ˈɹaɪt ðiː ɪˈkweɪʒən əv ə ˈfɪʃn̩ ɹiːˈækʃən ˈæz ˈɪt ˈfɪts ˈdʒʌst ˈwʌn ˈæɾəm,
ˈbʌt ˈɪn ɹiːˈæləɾɪ ˈðæt ˈwʌn ˈæɾəm ˈɪz sɚˈɹaʊndəd ˈbaɪ ˈmɛnɪ, ˈmɛnɪ ˈmɔr.
ənd ˈɪf ˈwʌn ˈlɪɾɫ̩ ˈnuːˌtɹɑn kən ˈtɹɪɡɚ ðə ɹiːˈækʃən ənd ˈðæt ɹiːˈækʃən ˈlɪbɚˌɹeɪts ˈθɹiː ˈmɔr ˈnuːˌtɹɑnz,
ˈwɛɫ ˈaɪ ˈθɪŋk ˈjuː kən ˈsiː ˈwɛr ˈðɪs ˈɪz ˈɡoʊɪŋ.
ˈɪf ðə ɹiːˈækʃən ˈɪzn̩t kənˈtɹoʊɫd ˈiːtʃ ɹiːˈækʃən ˈtɹɪɡɚ ˈθɹiː ˈmɔr,
ənd ˈɛvɹɪ ɹiːˈækʃən ɹɪˈliːsəz ðə ˈseɪm əˈmaʊnt əv ˈɛnɚdʒɪ, ˈwɪtʃ ˈædz ˈʌp ˈfæst.
ˈðɪs ˈɪz ˈpɹɪɾɪ ˈmʌtʃ ðə ˌdɛfəˈnɪʃən əv ə ˈtʃeɪn ɹiːˈækʃən
ənd ˈɪt ˈɪz ðə ˈbeɪsəs əv ðə ɹɪˈmɑrkəbəɫ ˈpʰaʊɚ əv ðə ˈnuːkliːɚ ˈwɛpən.
ðə ˈseɪm ˈtʰaɪp əv ɹiːˈækʃən əˈkʰɝz ˈɪn ˈnuːkliːɚ ˈpʰaʊɚ ˈplænts,
ˈbʌt ˈðoʊz ɹiːˈækʃənz ˈɑr kənˈtɹoʊɫd ˈɪn ˈsɛvɚɹəɫ ˈweɪz ˈtʰuː ˈkʰiːp ˈðɛm fɹəm ˈɡɛɾɪŋ ˈaʊt əv ˈhænd.
ðə ˈfækt ˈɪz ˈðiːz ˈtʃeɪn ɹiːˈækʃənz ˈhæv ðə pəˈtʰɛnʃəɫ ˈtʰuː pɹəˈduːs ˈfɑr ˈmɔr ˈhiːt ˈðæn ðə ˈplænt kən ˈjuːz,
ˈsoʊ ˈmʌtʃ ˈmɔr ˈðæt ðə ˈtʰɛmpɹəˌtʃʊr kən ˈiːzəlɪ ˈɹaɪz ˈtʰuː ˈdeɪndʒɚɹəs ˈlɛvəɫz, ɪˈnʌf ˈtʰuː ˈmɛɫt ðə jʊˈɹeɪniːəm.
ˈðɪs ˈɪz ðə ˈmɛɫtˌdaʊn ˈðæt ˈjuː ˈhɪr əˈbaʊt
ənd ˈmoʊst ɹiːˈæktɚ ˈkʰɔrz ˈɑr ɪˈmɝst ˈɪn ˈwɔɾɚ ˈtʰuː dɪˈspɝs ðə ˈhiːt ənd pɹɪˈvɛnt ˈðɪs fɹəm ˈhæpənɪŋ.
ˈbʌt ˈðæt, ˈðæts ˈnɑt ɪˈnʌf ˈɔn ˈɪts ˈoʊn ˈtʰuː kənˈtɹoʊɫ ˈðɪs ˈθɪŋ.
If the chain reaction is allowed to run freely,
no amount of water can remove the heat fast enough to prevent a meltdown.
A real way we control nuclear reactions is with control rods.
They're made of materials that readily absorb neutrons
and they're inserted between the fuel rods of uranium to slow the neutrons down and therefore slow the reaction.
They can be put in more to slow the reaction more, and lifted out more if you need more heat.
Now the other sticky wicket of fission reactions is the stuff that's left behind.
These reactions not only produce products that are still radioactive,
they produce tons of them, lots of different troublesome kinds.
Like we saw last week, uranium undergoes many different types of nuclear decay,
so not only does each uranium atom produce isotopes of krypton and bromine,
but that process also produces many other isotopes of other elements.
And as these various nuclei break down they release more neutrons
and more unstable products and the process continues for a long time.
All of these reactions eventually yield stable products
but they have half-lives ranging from a few years to tens of millions of years.
The products with shorter half-lives stabilize pretty quickly
but they release particles and energy like crazy during that time so they're extra dangerous.
The ones with longer half-lives decay more slowly, release less energy
but that means it takes a very, very long time for them to stabilize.
So long in fact, that for human purposes, it may as well be forever.
That means they'll always be an issue in our environment which is why we're always looking
for ways to store them, and keep them out of our way.
Fusion reactions, as you'd expect, are very different from fission.
For one thing, the energy released in many fusion reactions dwarfs even the huge amount released by fission.
You might be familiar, for example, with the wonderful work done by our sun.
The reactions that power the sun are like most fusion reactions,
in that they involve very small nuclei like isotopes of hydrogen and helium.
This reaction begins when two atoms of hydrogen,
accelerated by the sun's fantastically high temperatures and contained by its high pressures,
join to form an atom of deuterium, an isotope of hydrogen.
This fusion of particles releases a positron and some heat energy in the process.
Then another atom of hydrogen is joined to the deuterium to form helium-3.
This step also releases a lot of energy in the form of gamma radiation.
When two atoms of helium-3 are available they join together to form an atom of helium-4,
as well as two atoms of regular hydrogen which then can be used to begin the process all over again.
This final step also, as you might imagine, releases a large amount of energy in the form of mostly gamma radiation.
So this is a chain reaction too, but it's not a self-perpetuating one like we saw before.
This reaction requires a total input of 6 atoms of hydrogen but it only produces two,
in the end the remaining mass being released in the form of helium.
For this reason more fuel is always needed,
which is why our sun is going to run out of hydrogen in about 5 and a half billion years.
We can produce fusion reactions here on Earth too,
but they're not very useful for us because we haven't figured out how to control them.
They're super useful if you just want to blow up a big city though,
just to be clear, depending on your definition of use.
One reason is, as you can see on the mass-energy graph,
light nuclei that fuse together undergo a much larger energy change than heavy nuclei that break apart.
That means their reactions release far more energy than fission reactions do,
so much more that it's nearly impossible to contain and therefore use.
Also, because fusion involves joining nuclei,
the reaction has to overcome the really strong repulsion that naturally exists between their positive charges.
For this reason, fusion reactions can only occur when particles collide at very high speeds,
or under very high pressures.
At these mind-blowing speeds, the kinetic energy of the particles produces insane temperatures,
like in the 100 million kelvin range,
at which point, the material being accelerated actually exists in the form of plasma.
So not only are those speeds really hard to reach but material at that temperature, how do you control that?
Which is why we can't use fusion for things like generating electricity which would be super nice.
We've only found applications for it when we don't need to control it at all like in nuclear weapons.
So as you can tell, there is plenty of room for new ideas in nuclear chemistry.
Fusion would be really great because it would produce a lot of energy
and you'd just get helium out of the process and helium is awesome!
How can we use radioactive materials more efficiently?
Is there a way to achieve the speeds and manage temperatures that come with fusion?
And how can we do this stuff without blowing our faces off?
You've already taken the first step by learning the basics.
It's up to you how far you want to go from here.
Maybe you'll write the next totally crazy ingenious and counter intuitive equation that takes us to the next level.
For now though, thank you for watching this episode of Crash Course Chemistry.
If you paid attention, you learned how Einstein's famous formula helps us calculate
the binding energy of a nucleus from its mass defect.
You also learned the difference between fission and fusion.
You saw an example of each one.
and you learned about their applications in the real world.
This episode of Crash Course Chemistry was written by Edi González and edited by Blake de Pastino.
Our chemistry consultant is Dr. Heiko Langner.
It was filmed, edited and directed by Nicholas Jenkins. Our script supervisor is Caitlin Hofmeister.
Michael Aranda is our sound designer and our graphics team is Thought Café.