MAGNOLIA SOLAR FURNACE EXPERIMENT

Many  years  ago,  my  wife  and  I  regularly  babysat  little  Lesle  Nhu  Kieu,  the  daughter  of  our  Vietnamese  neighbors,  on  Saturdays,  when  both  of  her  parents  were  working.  I  was  the  main  caretaker,  and,  man,  I  loved  that  little  punk.  And  like  me  she  was  a  "lefty"  --  the  most  left  "lefty"  I  have  ever  seen  --  and  I  think  because  I  was  a  "lefty"  also  not  only  was  she  a  "tomboy"  who  loved  spending  time  with  me,  but  she  could  almost  read  my  mind.

If  I  wasn't  helping  little  Lesle  with  her  homework,   she  would  always  ask  to  go  on  some  "adventure"  or  other.   We  did  many  really  cool  things  --  we  toured  the  Franklin  Institute  in  Philadelphia,  the  University  of  Pennsylvania  Archaeology  Museum,  the  Academy  of  Natural  Sciences  Museum;  we  would  go  on  photography  walks,  taking  pictures  of  interesting  things  along  the  route;  I  took  her  flying,  once;  we  would  also  do  back  yard  experiments,  which  she  loved  more  than  anything  else.

One  of  our  backyard  experiments  was  the  construction  of  a  solar  furnace.

I  had  told  her  the  story  of  Archimedes  and  the  Roman  ships  attacking  his  City  of  Syracuse,  Sicily.  He  had  the  city  of  Syracuse  prepare  about  6,000  highly-polished  copper  shields,  with  a  man  assigned  to  each  shield,  and  stationed  them  around  the  harbor  of  Syracuse.  When  the  invading  Romans  sailed  their  barges  full  of  troops  into  Syracuse  harbor,  all  6,000  shield  bearers  carefully  reflected  the  sunlight  to  the  same  spot  on  each  barge,  multiplying  the  reflected  sunlight  by  6,000,  sending  a  blinding  reflection  of  sunlight,  as  hot  as  lava  from  a  volcano,  onto  each  barge,  cooking  the  troops,  and  setting  the  barge  afire.

When  I  told  little  Lesle  that  we  could  imitate  what  Archimedes  did  in  an  experiment,  she  looked  forward  to  it  with  enormous  enthusiasm.   I  began  buying  $1  mirrors  from  our  local  dollar  store ...

... until  I  had  accumulated  60  of  them,  and  then,  one  cloudless  Fall  Saturday,  Lesle  and  I,  and  a  neighbor  kid  named  Andrew  who  had  a  kind  of  crush  on  Lesle,  went  down  to  the  local  ballfield  for  the  experiment  with  our  mirrors.

We  set  up  an  overturned  trash  can  on  the  south  side  of  some  bleachers,  and  placed  a  black  plastic  flowerpot  on  the  trash  can,  and  I  said,  "This  is  a  wooden  barge  of  the  Romans  sailing  into  Syracuse  harbor";  and  the  3  of  us,   Lesle,  Andrew  and  myself,  then  carefully  set  up  in  an  array  all  60  mirrors  on  the  bleachers,  so  that  the  sunlight  reflecting  off  each  mirror   landed  on  the  same  spot  on  the  black  flower  pot.

As  the  concentrated  sunlight  on  the  flower  pot  from  the  addition  of  the  reflection  of  each  succeeding  mirror  grew  brighter  and  brighter,  it  became  so  brilliant  in  its  intensity,  even  on  black  plastic,  that  it  became  hard  to  look  at.  The  side  of  the  plastic  flower  pot  began  to  smoke  and  melt,  and  finally  it  caught  fire.

Voila:  With  a  few  dollars  of  junk  mirrors,  little  Lesle  and  Andrew  had  helped  me  prove  that  Archimedes  could,  indeed,  have  saved  his  beloved  City  of  Syracuse  against  invading  Romans  with  a  kind  of  "ray  gun"  powered  by  sunlight!