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Atomic Science
 

Atomic Science

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How do we use the atom to generate electricity?

How do we use the atom to generate electricity?

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    Atomic Science Atomic Science Presentation Transcript

    • Atomic  Science  Introductory  Physics/  Environmental  Science   Canadian  Academy   Alpha  decay  image  from  h3p://en.wikipedia.org/wiki/Alpha_decay
    • Atomic  Science Unit  Ques?ons:  “?”     Enduring  Understandings:     •  Nuclear  energy  can  be  used  to  generate  electricity     Areas  of  interac9on:     Human  Ingenuity    The  development  of  electrical  technologies  revolu6onised  culture     Environments    Can  we  maximise  efficiency  in  order  to  maximise  sustainability?   Criterion   Assessment  Tasks C:  Unit  Test E:  Half-­‐life  inves?ga?on A  &  B:  One  World  
    • Draw  an  Atom! What  are  the  names,  sizes,  charges  and  posi?ons  of  the  components?   What  is  the  relevance  of  this  to  radioac?vity?  
    • The  Ob-­‐Scertainer How  can  we  really  know  what  we  cannot  see?     Science  is  a  process  of  observa?ons,  hypotheses  and  tes?ng.     1.  Take  4  or  5  ob-­‐scertainers.  Play  a  bit.  Predict  the  shape  inside.     2.  Test  your  hypothesis  with  careful  movements  and  observa?ons.     3.  Draw  your  ‘final’  structure.  Conclude.     Play,  predict,  draw Modify,  conclude Test   4.  Have  an  ob-­‐scertainer  class  conference  and  come  up  consensus  on   the  best  structure  of  each  of  the  dishes  (there  are  12  in  total).    
    • The  Ob-­‐Scertainer
    • Atomic  Terminology Define  these  terms  and  then  arrange   them  into  a  mind-­‐map  or  diagram.   Atom     Nuclide     Nucleus  &  Nucleons     Atomic  Number  (Z)     Mass  Number  (A)     Neutrons  (N)     Isotope    
    • Atomic  Terminology Define  these  terms  and  then  arrange   them  into  a  mind-­‐map  or  diagram.   Atom:  ‘un-­‐cu3able’  –  the  smallest  unit  of  an  element     Nuclide:  an  atom  specified  by  an  atomic  and  mass  number     Nucleus  &  Nucleons  –  protons  (+)  and  neutrons  (0)  in  a  nucleus     Atomic  Number  (Z)  –  number  of  protons  in  the  nucleus,  defines  the  element     atomZahl Mass  Number  (A)  –  number  of  nucleons.  Defines  the  isotope.       Neutrons  (N)  =  mass  number  –  atomic  number     Isotope  =  atoms  of  the  same  element  with  different  mass  numbers.                                        
    • Protons  vs  Neutrons Work  through  the  periodic  table  and  plot  every  figh  element.     What  trends  and  pa=erns  can  you  iden?fy?     Can  you  suggest  a  reason  for  this? Mass  Number  (A)   Mass  Number  (A)   12 Atomic  Number  (Z) 6 C Neutrons  (N)  =  mass  number  –  atomic  number Atomic  Number  (Z)   8   Grid  from  Desmos  the  online  graphical  calculator  h3ps://www.abe3ercalculator.com/c
    • Radioac9ve  Stability Think  about  all  those  posi?vely-­‐charged  protons  next  to  each  other.      What  do  they  want  to  do?              What  happens  if  you  add  more  protons?       Alpha  decay  image  from  h3p://en.wikipedia.org/wiki/Alpha_decay
    • Radioac9ve  Stability Think  about  all  those  posi?vely-­‐charged  protons  next  to  each  other.    What  do  they  want  to  do?  What  happens  if  you  add  more  protons?    This  repulsive  force  is  the  electromagne9c  force.    It  is  not  par?cularly  strong,  but  acts  over  a  large  distance.      So  how  does  the  nucleus  stay  together?     electromagne?c  force   Alpha  decay  image  from  h3p://en.wikipedia.org/wiki/Alpha_decay
    • Radioac9ve  Stability Think  about  all  those  posi?vely-­‐charged  protons  next  to  each  other.    What  do  they  want  to  do?  What  happens  if  you  add  more  protons?    This  repulsive  force  is  the  electromagne9c  force.    It  is  not  par?cularly  strong,  but  acts  over  a  large  distance.      So  how  does  the  nucleus  stay  together?     electromagne?c  force  The  strong  force  acts  between    neutrons  and  protons.    It  s?cks  them  together  (using  gluons  –  yes,  really).    The  strong  force  is  strong,  but  acts  only     strong  force over  a  ?ny  distance.  As  the  size  of  the  atom  increases,  more  neutrons  are  required  to    keep  it  stable.       Alpha  decay  image  from  h3p://en.wikipedia.org/wiki/Alpha_decay
    • Radioac9ve  Decay When  the  forces  inside  the  nucleus  are  unbalanced,  decay  occurs.    What  condi?ons  favour  these  different  forms  of  radioac?ve  decay?      h3p://phet.colorado.edu/en/simula?on/alpha-­‐decay -­‐ -­‐ Gamma  decay  ( )  is  high-­‐frequency  energy  which   accompanies  other  forms  of  decay.     h3p://phet.colorado.edu/en/simula?on/beta-­‐decay Alpha  decay  image  from  h3p://en.wikipedia.org/wiki/Alpha_decay
    • Radioac9ve  Decay Radioac?ve  decay  is  a  natural,  random  change  in  atomic  nuclei  that  goes  on  all  around  us.  Radioac?ve  materials  are  going  through  radioac?ve  decay.    In  this  group  task,  find  out  about  one  type  of  decay  and  explain  to  others.     Alpha  decay  symbol:  (      ) Beta-­‐  decay  symbol:  (      ) Gamma  Decay  symbol:  (  γ  ) Nucleus  is  too  large  and   Nucleus  has  too  many… Nucleus  has  too  much   posi?ve.   energy  ager  α  or  β  decay.   ___________  is  released   _________  and  _______  are   A  gamma  ray  is  released   from  the  nucleus. released  from  the  nucleus. from  the  nucleus.   The  alpha  par?cle  is  a  stable   The  beta-­‐par?cle  is  a  fast-­‐ The  gamma  ray  is  a  photon   ___________  nucleus  (__   moving… of  high-­‐frequency  energy.   protons  and  ___  neutrons) Diagram: Diagram: Penetra?ng  ability: Penetra?ng  ability: Penetra?ng  ability:   Will  pass  through  thin  lead.   Image  from:  h3p://en.wikipedia.org/wiki/Gamma_decay#Gamma_ray_produc?on
    • Radia9on Radioac?ve  decay  emits  radia?on  in  different  forms.    Radia?on  is  considered  harmful  if  it  is  ionizing.  This  means  it  interacts  with  electrons  in  living  things,  causing  them  to  become  ionised.    This  results  in  free  radical  forma?on,  and  lots  of  damage  to  cells  and  ?ssues.      When  damage  is  caused  to  DNA,  this  can  lead  to  cancers.      Although  α    radia?on  is  easily  stopped,  it  may  be  dangerous  if  inhaled  or  ingested.     par?cles energy Penetra?on  image  from  h3p://en.wikipedia.org/wiki/Radia?on  
    • Decay  Equa9ons  Decay  (proton:  neutron  ra?o  too  high)  An    par?cle  (He)  is  always  lost.   Mass  number  decreases  by  4.   Atomic  number  decreases  by  2.     235 4 ? 92 U! 2 He + ? X 4 He 2 40 4 ? 19 K! 2 He + ? X 209 205 ? 84 Po ! 82 Pb + ? ? Some  gamma  energy  is  released,   but  is  not  a  par6cle  (so  does  figure   in  our  equa6ons) Alpha  decay  image  from  h3p://en.wikipedia.org/wiki/Alpha_decay
    • Decay  Equa9ons -­‐  Decay  (too  many  neutrons)   -­‐  Decay  (too  many  neutrons)  A  neutron  decays  into:   Neutron  decays  into  proton.    •  Proton  (remains  in  nucleus)   Electron  and  an?neutrino  released.   •  -­‐  par?cle  (fast  electron)  •  An?neutrino  Some  gamma  energy  is  released,  but  is  not  a  par6cle  (so  does  figure  in  our  equa6ons) Alpha  decay  image  from  h3p://en.wikipedia.org/wiki/Beta_decay
    • Decay  Equa9ons  Decay  (proton:  neutron  ra?o  too  high)   -­‐  Decay  (too  many  neutrons)  An    par?cle  (He)  is  always  lost.   Neutron  decays  into  proton.     Electron  and  an?neutrino  released.   235 4 231 92 U! 2 He + 90 Th40 4 3619 K! 2 He + 17 Cl209 205 4 plus  Decay  (too  many  protons)   84 Po ! 82 Pb + He 2 Proton  decays  into  neutron.  Posi?ve   electron  (positron)and  neutrino  released.  
    • Radioac9ve  Decay  of  Uranium  238 It  takes  billions  of  years  and  many  cycles   of    decay    and   -­‐    decay  for  radioac9ve   238U  to  become  stable  206Pb.       Work  through  the  puzzle  on  the  sheet,   prac?cing  the  decay  equa?ons  and  proper   nota?on  of  the  isotopes  as  you  go.                 If  you  finish:     Find  out  more  about  ‘half  life’.     What  does  it  mean?    
    • Decay  Lab Carry  out  this  inves6ga6on  to  learn  more  about  half-­‐lives.     Assessed  for  Criterion  E:  Processing  Data.   100  Green  beads   100  White  beads   Radioac?ve  green  beads  decay  into  white  beads.     This  process  is  random.       Record  the  start  ?me.       Remove  4  greens  from  the            cup  and  put  in  ‘discard’.   2.  replace extra     Replace  with  white  4  daughter  beads.     daughters Record  “4”  as  the  number  of  greens  removed.       Cover,  shake  and  select  4  at  random  again.     white Count  and  record  the  greens.  Discard  and  replace.    1.  random  4  sample   green Repeat  un?l  20  random  samples  have  been  taken.     Record  the  number  of  greens  each  ?me.     discard   Record  the  finish  ?me.   Total  ?me/20  =  mean  ?me  per  sample.  Record.       How  could  you  graph  these  data   Reset  the  simula9on  and  repeat,     and  use  them  to  calculate  the  half   this  9me  taking  8  beads  at  random  per  sample.     life  of  the  green  beads?
    • Decay  Lab Carry  out  this  inves6ga6on  to  learn  more  about  half-­‐lives.     Assessed  for  Criterion  E:  Processing  Data.   100  Green  beads   100  White  beads   Decreasing Increasing 2.  replace extra     daughters white 1.  random  4  sample green discard Total  6me  for  each  experiment When  you  have  finished  the  sampling,  save  and   20  cycles  of  random  sampling  –  4  at  a  9me.     send  to  your  partner.  You’re  on  your  own  now.     Then:   Go  to  Tools  –  Protec6on  –Unprotect  Sheet  to  be   able  to  complete  the  rest  of  the  task.   Reset  the  simula9on  and  repeat,     this  9me  taking  8  beads  at  random  per  sample.    
    • Decay  Lab Carry  out  this  inves6ga6on  to  learn  more  about  half-­‐lives.     Assessed  for  Criterion  E:  Processing  Data.   Plot  best-­‐fit  decay  curves  (no  need  for  the  increases).  Adjust  the  polynomial  order  so  the  curves   are  smooth  and  realis?c.  Remove  the  labels  for  the  curves  which  will  appear  in  this  legend.  
    • Decay  Lab Carry  out  this  inves6ga6on  to  learn  more  about  half-­‐lives.     Assessed  for  Criterion  E:  Processing  Data.   Calcula9ng  Half  Life   For  each  curve,  find  as  many   ‘half  intervals’  as  possible  (e.g.   100-­‐>50,  80-­‐>40,  60-­‐>30).       Take  a  mean  of  these  half   intervals.  This  is  an  es?mate  of   the  half-­‐life  of  the  isotope.       What  differences  do  you  find   between  the  4-­‐sample  and  the   8-­‐sample?  Which  es?mate  of   half  life  is  more  reliable?  Why?     Plot  best-­‐fit  decay  curves  (no  need  for  the  increases).  Adjust  the  polynomial  order  so  the  curves   are  smooth  and  realis?c.  Remove  the  labels  for  the  curves  which  will  appear  in  this  legend.  
    • Decay  Lab Carry  out  this  inves6ga6on  to  learn  more  about  half-­‐lives.     Assessed  for  Criterion  E:  Processing  Data.   Plot  best-­‐fit  decay  curves  (no  need  for  the  increases).  Adjust  the  polynomial  order  so  the  curves   are  smooth  and  realis?c.  Remove  the  labels  for  the  curves  which  will  appear  in  this  legend.  
    • Decay  Lab Carry  out  this  inves6ga6on  to  learn  more  about  half-­‐lives.     Assessed  for  Criterion  E:  Processing  Data.   In  the  conclusion,  work  through  this  scenario.     Assume  that  in  the  4-­‐sample  test,  1  minute  represents  100  years.     For  the  material  to  be  considered  ‘safe’,  it  needs  to  decay  to  1/16  of  its  original  amount.       Answer  the  following  ques9ons,  with  jus9fica9on.       •  How  long  do  you  need  to  be  concerned  about  the  material?       •  How  might  you  store  it  safely  for  that  long?  
    • Decay  occurs  at  random  –  we  can’t  predict  when  an  individual  Half  Life atoms  will  decay.  However,  we  can  predict  the  rate  at  which  large   quan??es  will  decay,  and  this  is  called  half-­‐life.   “The  radioac6ve  half-­‐life  for  a  given  radioisotope   is  the  6me  for  half  the  radioac6ve  nuclei  in  any   sample  to  undergo  radioac6ve  decay.”   Hyperphysics   (h=p://hyperphysics.phy-­‐astr.gsu.edu/hbase/nuclear/halfli.html) Use  this  PhET  Lab  to  find  out  more  about   half  lives  of  13C  and  238U  and  how  they   can  be  used  to  es?mate  the  age  of   geological  materials.  Cool.   h3p://phet.colorado.edu/en/simula?on/radioac?ve-­‐da?ng-­‐game
    • Biological  Effects  of  Radia9on Ionising  radia?on  can  damage  living  ?ssues  by  causing  atoms  to  become  ions,   which  can  in  turn  become  damaging  free-­‐radicals.     Infographic  from:  h3p://www.theglobeandmail.com/news/world/asia-­‐pacific/how-­‐ radia?on-­‐affects-­‐the-­‐body/ar?cle1942117/?from=1942081
    • Biological  Effects  of  Radia9on Infographic  from:  h3p://www.theglobeandmail.com/news/world/asia-­‐pacific/how-­‐ radia?on-­‐affects-­‐the-­‐body/ar?cle1942117/?from=1942081
    • Uses  of  Nuclear  Radia9on Find  out  more  about  these  uses  of  radia?on:   •  What  type  of  radia?on?   •  How  is  it  used?  da?ng Rad iocarbon Sterilising  fo od  &  medical  e quipment Radioac?ve  tracers  &  diagnosis Radiotherapy:  cancer  treatment Smoke  detec tors
    • Some  Decays.  Which  are  α  and  which  are  β-­‐? 238 4 234 218 4 214 92 U! 2 He + 90Th 84 Po ! 2 He + 82 Pb 214 0 214 234 90 Th ! 0 "1 e+ 234 91 Pa +! 82 Pb ! "1 e+ 83 Bi +! 214 0 214 234 91 Pa ! 0 "1 e+ 234 92 U +! 83 Bi ! "1 e+ 84 Po +! 234 4 230 214 4 210 92 U! 2 He + 90Th 84 Po ! 2 He + 82 Pb 210 0 210 230 Th ! 4 He + 226 Ra 82 Pb ! "1 e+ 83 Bi +! 90 2 88 210 0 210 226 4 222 83 Bi ! "1 e+ 84 Po +! 88 Ra ! 2 He + 86 Rn 210 4 206 222 4 218 84 Po ! 2 He + 82 Pb 86 Rn ! 2 He + 84 Po 29  
    • Which  is  the  correct  α  decay  equa?on?  Which  is  the  correct  β-­‐  decay  equa?on? A.   B.   238 4 234 214 0 214 92 U! 2 He + 90 Th 82 Pb ! +1 e+ 83 Bi +! C.   D.   234 0 234 214 1 213 91 Pa ! "1 e+ 92 U +! 84 Po ! H + 1 83 Bi Which  product  is  correct? A.   222 B.   222 87 Fr 86 Rn 226 4 ? 88 Ra ! 2 He + ? ? C.   225 223 D.   80 U 86 Rn Which  product  is  correct? A.   222 B.   222 234 0 ? 87 Fr 86 Rn 90 Th ! "1 e+ ? ? +! C.   238 234 D.   92 U 91 Pa
    • Which  product  is  correct? A.   17 B.   18 9 F 9 F 17 4 ? 8 O! 2 He + ? ? C.   13 D.   13 C 6 C 7 Which  product  is  correct? A.   211 B.   210210 0 ? 83 Bi 83 Bi 82 Pb ! "1 e + ? +! ? C.   206 D.   214 80 Hg 84 Po Which  product  is  correct? A.   220 B.   210 84 Po 83 Bi ? 4 235 ? ?! 2 He + U 92 C.   206 D.   239 80 Hg 94 Pu
    • Check  the  periodic  table.  Which  are  the  most  common  isotopes? A.   14 B.   12 A.   211 B.   209 6 C 6 C 83 Bi 83 Bi C.   12 C.   209 6 C D.   13 C 7 84 Bi D.   208 83 Bi Which  nuclide  is  correct? A.   137 B.   141 ? 0 137 55 Cs 58 La ? ?! "1 e+ 56 Ba +! C.   135 D.   131 55 Cs 53 Xe Which  nuclide  is  correct? A.   220 B.   236 84 Po 95 Am ? 4 237 ? ?! 2 He + 93 Np C.   241 D.   233 95 Am 91 Pa
    • Where  does  our  energy  come  from?
    • Where  does  our  energy  come  from? Nuclear  fusion  reac?ons  occur   in  the  core  of  the  Sun.       How  does  the  Sun’s  energy  give   us  the  energy  we  use  on  Earth? 1.  Core   5.  Chromosphere   6.  Corona   2.  Radia?ve  zone   7.  Sunspot   3.  Convec?ve  zone   8.  Granules   4.  Photosphere   9.  Prominence  Images  from:h3p://en.wikipedia.org/wiki/Sun
    • Nuclear  Fusion is  how  the  Sun  generates  energy! Iden?fy  these  nuclei.       What  happens  here?       What  are  the  products?       What  is  this?   What  nuclear  force  must  be  overcome  in   order  for  fusion  t  occur?       For  us  to  achieve  this  on  Earth  takes  massive   amounts  of  energy  and  resources.  Fusion  is   not  (yet)  a  realis?c  way  of  genera?ng  energy.     Images  from:  h3p://en.wikipedia.org/wiki/Nuclear_fusion
    • Nuclear  Fusion is  how  the  Sun  generates  energy…   …  but  we  can’t  reliably  do  it  here  on  Earth.   Nuclear  Fission is  what  we  mean  by  atomic  energy.   Images  from:  h3p://en.wikipedia.org/wiki/Nuclear_fusion
    • Nuclear  Fission is  how  we  generate  ‘atomic  energy’.   Open  this  PhET  Lab  on  Fission.       Describe  how  a  fission  reac?on  works.     •  What  is  the  role  of  the  neutron?   •  What  happens  to  the  235U  nuclide?   •  How  is  energy  released? Switch  to  the  Chain  Reac9on   Set  it  up  in  a  containment  vessel.     •  What  happens  when  you  add  more  235U?   •  How  does  238U  behave?   •  Which  isotope  would  you  choose  to  sustain  a   chain  reac?on,  releasing  energy? Switch  to  the  Nuclear  Reactor   Set  it  up  and  get  it  running!   •  What  is  the  effect  of  removing  the  control   rods  from  the  reactor?  h3p://phet.colorado.edu/en/simula?on/nuclear-­‐fission •  How  could  control  rods  be  used  to  maintain   safety  and  control  output  of  energy?   •  What  are  they  made  of?
    • Nuclear  Fission is  how  we  generate  ‘atomic  energy’.   Annotate  this  diagram  to  describe  what  is  happening  in  a   1  neutron  in   nuclear  fission  reac?on.       This  fission  equa9on  represents  the  reac?on:     235   92 U + 01n ! 3 01n + 141Ba + 36 Kr 56 92     Complete  these  fission  equa?ons:     235 92 U + 1n ! 3 1n + 90 Rb + ? ? 0 0 37 ? energy 235 92 U + 01n ! 3 01n + 143 55 Cs + ? ? ? 3  neutrons   These  neutrons  can  go  on  to  split  other    produced 235U  nuclides  in  a  chain  reac6on.   Image  from:  h3p://en.wikipedia.org/wiki/Nuclear_fission
    • Nuclear  Energy how  do  we  get  electricity  from  this?   It  takes  a  lot  of  binding  energy  to  hold  a  nucleus  together.       When  we  split  the  atom,  we  release  the  daughter  par?cles,   some  neutrons  and  gamma  radia?on.  Gamma  radia?on  is   high-­‐frequency  energy!       This  energy  can  be  used  to  heat  water,  to  drive  a  turbine  and   power  a  generator,  just  like  conven?onal  electrical  genera?on.       It  all  needs  magnets  to  move  in  rela9on  to  coils!     Control-­‐rods  are  neutron-­‐absorbent   materials  that  can  stop  or  control  the   rate  of  the  chain  reac?on  and   therefore  control  the  temperature  and   safety  of  the  reactor.   Images  from:  h3p://en.wikipedia.org/wiki/Nuclear_fission      and  h3p://en.wikipedia.org/wiki/Pressurized_water_reactor
    • Radioac9ve  Waste How  do  we  get  rid  of  it? The  products  of  nuclear  fission  are  radioac?ve  but  will  decay  to  stable  nuclides.       141Complete  the  decay  pathways  for  92Kr  and  141Ba.     92 36 Kr 56 Ba   -­‐,  1.8s ??,  18.3  min     92 141 ? ? ? ? ??,  4.5s ??-­‐,  3.9  h   92 141 ? ? ? ? ??,  2.7h ??-­‐,  32.5  days     92 141 ? ? ? ? ??,  3.5h Data  from:  h3p://periodictable.com/Isotopes/056.141/index2.p.full.dm.html
    • Radioac9ve  Waste How  do  we  get  rid  of  it? The  products  of  nuclear  fission  are  radioac?ve  but  will  decay  to  stable  nuclides.       141Because  nuclear  waste  is  radioac?ve,  it  needs  to   92 36 Kr 56 Ba -­‐,  1.8s -­‐,  18.3  min   be  isolated  un?l  it  has  decayed  to  a  safe  level.  This  could  be  underground  or  in  special  treatment   92 141facili?es.     37 Rb 57 La   -­‐,  4.5s -­‐,  3.9  h     92 141Nuclear  reprocessing  plants  can  take  the  spent  fuel   38 Sr 58 Cerods  and  extract  fissionable  materials,  such  as   -­‐,  2.7h -­‐,  32.5  days     plutonium,  from  them.  These  can  be  used  in  other  reactors.     92 141   Y 39 59 Pr -­‐,  3.5h  Next  genera?on  nuclear  reactors  will  use  current   92nuclear  waste  as  fuel.     40 Zr     Data  from:  h3p://periodictable.com/Isotopes/056.141/index2.p.full.dm.html
    • Can  nuclear  fission  power  the  planet? 42  
    • Fission,  Fusion,  α-­‐Decay  or  β–Decay? 1.     235   92 U + 01n ! 3 01n + 143 Cs + 55 90 37 Rb   2 2.     1 H + 1 H ! 01n + 3 4 2 He + energy     3.     238 4 234   92 U! 2 He + 90 Th   4.     214 0 214 82 Pb ! "1 e+ 83 Bi +!     235 5.     92 U + 01n ! 3 01n + 141 56 Ba + 92 36 Kr     40 4 36 6.     19 K! 2 He + 17 Cl 32 0 32   15 P! "1 e+ 16 S +!   214 0 214 131 0 131 7.   83 Bi ! "1 e+ 84 Po +! 53 I! "1 e+ 54 Xe +! 43  
    • What  do  you  think? Ideas  based  on     Concept  Cartoons:   h3p://www.conceptcartoons.com   Clipart  people  from:  h3p://www.clker.com/search/krug/1
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