Coin lab

EXPERIMENT: Physics of The Atom AIM: To illustrate illustrate the nature of half-life through the use of analogous systems. THEOR: Half-life !t "# is the time re$uire% for a $uantity to fall to half its &alue as measure% at the the 'egi 'eginni nning ng of the the time time (eri (erio% o%.. In (hysi (hysics cs)) it is ty(i ty(ical cally ly use% use% to %esc %escri ri'e 'e a (ro(e (ro(ert rty y of ra%ioacti&e ra%ioacti&e %ecay) therefore therefore ra%ioacti&e ra%ioacti&e half-life half-life for a gi&en ra%ioisoto(e ra%ioisoto(e is a measure measure of the ten%ency of the nucleus to %ecay or %isintegrate an% such is 'ase% (urely u(on that (ro'a'ility. The half-life is in%e(en%ent of (hysical state!soli%) li$ui% or gas#) tem(erature) (ressure) the chemical com(oun% in *hich the nucleus fin% itself an% any other outsi%e influences. It is also in%e(en%ent of the chemistry of the atomic surface. The only thing thing that has an im(act on the half-life of an o'+ect is %irect nuclear interaction *ith the (article from outsi%e. E,am(le: a high energy collision in an accelerator. Half-life can 'e use% for estimating the age of a %ea% organism. The amount of car'on- in the atmos(here has not change% in thousan%s of years. E&en though it %ecays %eca ys into nitrogen) ne* car'on- is al*ays 'eing forme% *hen cosmic rays hit atoms high in the atmos(here. Plants a'sor' car'on %io,i%e from the atmos(here an% animals eat  (lants. This means all li&ing things ha&e ra%ioacti&e car'on- in them. /hen an organism) eg a tree) %ies it sto(s ta0ing in car'on %io,i%e. The amount of car'on- in the *oo% %ecreases *ith time as it %ecays into nitrogen *ith a half-life of a'out 1233 years. 4y com(aring ho* much car'on- there is in the %ea% organism *ith the amount in a li&ing one) the age of the %ea% organism can 'e estimate% .

5ARIA46E7: 8ontrolle%: The coins use%) The can use%) The (lace *here the coins are thro*n Mani(ulate%: The num'er of thro*s Res(on%ing: The num'er of un%ecaye% atoms !t#

APPARAT97:: 33 8oins 8ylin%rical containertin

Michael  Timson Form: 4E

;IA
=ar 

8oins !Hea%s or Tail#

Michael  Timson Form: 4E

METHO;: . The total num'er of coin!un%ecaye% atoms# *as note% *here the num'er of thro*s!n#>3 ?. The coins *ere then (lace% into the +ar *here hea%s re(resente% %ecaye% atoms an% tails re(resente% un%ecaye% atoms. @. The can *as sha0en &igorously to ensure that the coins *ere mi,e% an% the coins *ere then an% *as then) flung an% scattere% on the floor. . The num'er of hea%s an% tails *ere counte% an% the un%ecaye% atoms *ere (lace% 'ac0  into the can 1. 7te(s @ an%  *as re(eate% until un%ecaye% atoms >  . The entire e,(eriment *as re(eate% of to o'tain a secon% set of rea%ings

RE796T7: TA46E 7HO/IN< THE BIR7T REA;IN< OB ;E8AE; AN; 9N;E8AE; 8OINTE; BOR EA8T THRO/

 No. of Thro*s

;ecaye%

9n%ecaye%

3

3

33



2

1@

?

?1

?C

@

1

@





D

1

1





@



Michael  Timson Form: 4E

TA46E 7HO/IN< 7E8ON; REA;IN<7 OB ;E8AE; AN; 9N;E8AE; 8OIN7 BOR EA8H THRO/  No. of Thro*s

;ecaye%

9n%ecaye%

3

3

33



11

1

?

D

?

@

3

@





D

1





8A6896ATION7: Half life from 33 > t-t? > .-3 >.

Half-life from C3 > t@- t? >.-3. >.3

Half-life from 3 > t-t1 > .D-.C >. A&erage half-life > !..3.#@ >. Michael  Timson Form: 4E

PRE8A9TION7: . The floor *as o'ser&e% an% ensure% that it *as clear from o'stacles that *ill (re&ent the  'all from rolling. ?. All the coins use% *ere of the same ty(e @. All the rea%ings *ere ta0en in the same location. . All the coins *ere tosse% using the same han% an% mo&ement. 1. All the coins counte% !%ecaye% an% un%ecaye%# *ere a%%e% u( to ensure that their total a%%e% u( to the (re&ious total amount of un%ecaye% atoms. . The floor *as fully scanne% after each rea%ing to ensure that all coin *ere counte% an% either (lace% asi%e or (lace% into the +ar. 2. The same (erson must %i% all the coin tossing. 7O9R8E7 OB ERROR: . ?. @. .

All the coins use% *oul%nFt ha&e 'een 33G i%entical. The same han% mo&ement *oul%nFt 'e33G i%entical e&ery time. The coins each time %i% not lan% on the same e,act (lace.
;I78977ION: The results of this e,(eriment is ran%om meaning that it *oul% &ary e&ery time the e,(eriment is con%ucte%) therefore if another classmate is to con%uct the same e,(eriment) they *oul% not o'tain the results as seen in the. If one coin is mar0e% *ith an X it cannot 'e  (re%icte% that it *ill %ecay) 'ecause ra%ioacti&e %ecay is a ran%om (rocess. Ra%ioacti&e %ecay) also 0no*n as nuclear %ecay or ra%ioacti&ity) is the (rocess 'y *hich a nucleus of an unsta'le atom loses energy 'y emitting (articles of ioniing ra%iation. Ra%ioacti&e %ecay is a ran%om (rocess at the le&el of single atoms) in that) accor%ing to $uantum theory) it is im(ossi'le to (re%ict *hen a (articular atom *ill %ecay. Ho*e&er un%erstan% an% characterie the %ecay of ra%ionucli%es on the 'asis of statistical analysis. Only 'y loo0ing at a large num'er  of atoms of a gi&en isoto(e of a gi&en element an% counting the %ecay e&ents o&er time can *e $uantify the %ecay rate. This is *hat the term half-life is use% to state) 'ase% on the statistics) *hen half of a gi&en $uantity of a su'stance *ill ha&e un%ergone ra%ioacti&e %ecay. This e,(eriment *as a en+oya'le e,(eriment an% a successful one. Im(ro&ement coul% 'e mane. An e,am(le of an im(ro&ement is that a smoother surface coul% ha&e 'een use% instea% of a rough one. The result in the ta'le sho*s that ra%ioacti&e %ecay occurs ran%omly. Brom the gra(h o'tain) three half li&fe *ere calculate% an% foun% to 'e .) .3 an% .3. Therefore it can 'e conclu%e% that the half life *as constant. 8ON8697ION: As seen in the t*o ta'les o'taine%) ra%ioacti&e %ecay ha((ens ran%omly. Ho*e&er the half-life as seen in the calculation *as constant. Michael  Timson Form: 4E