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ED 124 18 . 88 SE 019 612

TITLEN: Radioactivity .and Man iinicourse, Career Oriented

Pre-Technical Physics* , INSTITUTI N Dallas Independent School District, Tex. SPONS AGE CY Bureauvof Ele*entary and Secondary tducat4.0n (D5 HEN/OE),-WashingtOn, D.C. -RUB DATE 7 For rilated 0, NOTE - 78p.; Drawings may not reproduce wel documens, see SE 018 322-333 and SE 019 605-616

, . 4 EDRS PRICE MF-$0.83 HC-$4.67 Plus Postag4. DESCRIPTOR Instructional Materialsi Physics; *Program Guides; *Radiation Effects; *Science Activities; Science .41 Careers; Science Education; *Science Materials; Secondary Zdution;.*Secondary School Science; Technical Educe ion IDENTIFIrRS Elementary Seco dart' VIAlcation ACt Title III; ESEA Title' III 07.

1 ABSTRACT .1j This instructional guide, intended for student use, develops the subject of radioactivity and can through a series. of sequential activities.. `A technical development of the subject is pursued with examples stressing practical aspects'of the concepts. Included in the minicourse are:, (1) the rationale,(2) terminal behavioral objectives, (3) enabling behavioral objectives,(4) activities,(5) resource ,packages, and (6) evaluation materials. The' * benefits as well as the dangers of radiometivity to Ian are considered.,This unit is one of twelve intended for use in.the second year of tv9 year vocationally oriented .physics. program. (CP)

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***********************************************************************. * . Documents acquired by ERIC include many inforgal unpublished * materials not a40.1able.from other sources. ERIC makes every effort * * to obtiit the best copy available. Nevertheless,items of.marginel * *.reproducibility are often encountered and this-affects the quality *

- *`of the microfiche and hardcopy reproductions ERIC makes available * *. via the title Document Reproduction service (EDRS).EDRS'is not * responsible for the quality of the original document. Reproductions * * supplied by EDRS are the best that can be made from the' original. * **********************************************************4************ :3 CAREER. ORIENTED PRE-TECHNICAL PHYSICS., US DEPARTMENT OF HEALTH, NATIONALEDUCATION INSTITUTE & WELFARE OF TN EDUCATION Radioactivity and Man ESEA Title 111 Project MINICOURSE SENTSTATEDATLNGENED"..CCED_CATLDN PERSON CFFLVA). ED r,T DO EXACITO our.ta7s,CF NOTDR tiAlcONALORGAN,ZATEONDR,CI:N. NECESSAWLY Pcs,rici AS VIEW RECEGVED Cot ctiVNIUFEOR *ay.:*OPiN-0445 SFACAt DOCUMENT CF HAS SEEN REPAD. EPRE. 7975 I tl dallas indepehdent to) school dtstrict CAREER,ORIENTED PRE-TECHNICATL FEYSICS Radioactivity and-Man Minicourse

1 ESEA Title III Project . 1974 dallas independent sthool district EugeneBOARD S Smith. OF Jr.. EDUCATIQN Presdent Emmett J. Conrad. M.D7 Bill C. Hunter. Vice-President Lawrence Herkime .0, James Jennings Nandi` Judy. Robert Medrano Kathlyn Gilliam Sarah Haskins , , . ADMINISTRATIVE OFFICERS Nolan Estes 0 General Superintendent H. S. Griffin Associate Superintendent Deputy SuperintendentRogett.I. Barton Deveopment ..- 9. Assistant SuperintendenPAdaptive EducationFrances Allen AssIValyt--trpe.rsrleszcler-1 H. 13, Pearson Elos:rrez.'s Assistant Superintendent . Assistant Sup.grintenderrtOtto M. FriOia-;__Jr.Larry Ascough Communications Ass:star!PersOnnel ,Strproirefidect Development GeorgeJoe Reid M. Fitts Assistant SuperintendentProgram DevelopmentRubenlementary Gallegos WperationS Assistant SuperintendentSecondary CtienatorisJohn J. Santillo Personnel - nl Asistant to the- General Superintendent Carlton C.- Moffett . .Assistant.Supenntenclent B. J. Stamps Bect-Kiedeclen Attorney Assistant Superintendentinstructional Services.SupportWeldon Services Wells , c October 8, 1974 dabs indeOendent school district Nz]ari This Minicourse is a tesult of hard work, dedication, and a com- the regular"teachingThestaff,prehensive Minicourse college program professors,contains ofin testingclassroomthe teachers, Dallas and activities Independent improvementand others. designed Schoolby members for useof thein ,-District. whofinedently Independenthad4,part example wit') in closeofSchool designing,the teacher excellentDistrict supervisiontesting, isefforts known. and andfor improving aid.which the this Dallas Minicourse. Through minicourseactivities, students work indepen- May I commend all of those This work-is a I commend it to your he. Sincerely yours, rTh NE:mag Genera Superintendent ..7 -CAREER-OnIENTID PRE-TECHNICAL PHYSICS RADIOACTIVITY-AND blINICOURSE 3 ,RATIONALE (What this minicourse is about): but as nuclear technology becomes more widespread, needsman-madeRadioactivity to radiationlearn issomething naturally will become, about present themore basicsall and around more aus; part of radiat,ton technology, its benefits, and of our everyday environment. Therefore, everyone its hazards. radioactiveIn this minicourse'you radiation; andwill you, develop as a a moretinformedcitizen,better undeistanding can pass of on the to hazardsothers of, radioactive An effort will be made inforAation about materials and notradiation to be alarmistshazards and and precautions not to overemphasize radiation-hazards,to but to place taken to avoid unnecessary exposure. hazards of everyday life. Of course, a'llry real and the hazards of radio-17 weightyactive environmentalwastescavity and'reactor;fuels in a concernrealistic is perspectivethefor yetthe unsolvednumerous with otherproblem power reactors planned for use in of handling and long-term Storing of the immediate- radio- ure. a radiation'technology are'so greatisat our present civilization wouldTheradioisotopes benefits not endurewithout for to mankind discover thisderived the technology. nature from of a particular Let'sillness glance (diagnostic at a few tool) of7these benefits. the use of radioisotopes The use of tothe ture functio e particular illness (therapeutic tool), the use oi radioactive tracers to better, understand of-plents._aAd to thereby increase world food production, the usa,of radioactive isotopes tionsilizeto find taken'fromfood, ways and to`reduce thea list use wearof.thousandsof radioactive in engines of materialsandtechnological machine to parts;make applications. atomic the use batteries of radioactive are only radiation:to a very few appiica- ster- Inine this some minicourse of the general you will: properties of naturally occurring and man-made radioactive elements, (a) study the relgtionship of radioactivity to nuclear energy, (b) exam- - whichused(c) radioactivematerialsto investigateshow how radioactivity several pose means forbenefits 'of the-human detecting man. body; radioactivity. and at the same time, a whole section will be You will also study some of'the dange 'tion forAn understandingentering_into-a of largeradioactivity, variety of itsrelated properties, technical its ffelds. hazards, and its detection constitute:ajounda- For example, the field of medicine , theincludes, like. radiation research physicians, specialists in medical radioisotopes Also, t,ti.s minicourse will be useful to students who may become technicians in a cancer o X-ray technicians, and clinic, assistants to,==a&rmatologist, health physics technicians for specialized manufacturers whose -4r-- 4 / I; o'processesThese requirekinds of radioactive job prospects materials, are good; nuclear and therepoier hasplant been tehnicians, an increase or inphysics demand or forpore'technical science teachers: help '''' t q in most of these fields in recent 34ars. . -2- IY)ou . n otebook during this minicourse. , The notebook will contain accounts of 1 are expected to keep a .0 ) investigations (experiments), answers to questions, and newspaper and magazine articles related to- , , In addition to RATIONALE, thisradioactivity minicOursq containsand its applicationthe following to sections:everyday living. 4% , .2) ENABLING1) TERMINAL BEHAVIORAL BEHAVIORAL' OBJECTIVES OBJECTIVES (Learning (Specific-things usteps".Khich you will are enableexpected you to to learm eventually from this reach minicourse) the 3).ACTIVITIES' (Specific things tote do to help you learn) inal behavioral objectives) .. 4) RESOURCE PACKAGES (Specific instructions.for,performingcedures; references, laboratory the materials,learnineActi:vities, etc,') such aspro- 4 5)/EVALUATION (Teats to help youa)the learn Self-test(s)terminal and to behaviOral determine with answers objectives)whether to helpor not you you learn satisfactorily mor reach )6 TERMINAL IBEHAVIORAL OBJECTIVES b) Final tests; to measure your overall achievement. t. Upon the completion of this.minicourse, you will be able to: . 2)1) explain andthe illustrate.general relationship the general of differencesnatural andartificial between alpha transmutation particles, betato radioactivity. particles, and 3).denonstrate, gamma the rays. use of such counter,ins and the spinthariscope in . . hents detection as the electroscope, of radioactive the radiation,' cloud chamber, the Geiger . -3- 4) explain some of the dangers of radiation to the Litman body, when exposed externally or, - 6)5) explainwrite down how andradloactivity explain at isleastinternally. affecting ten (10) e'veryday_lMe different benefits today, basedof radioactivity on at least'four to.mapkpd." (4) clip' ENABLING BEHAVIORAL OBJECTIVE #1: pings ot writeups from current newspaper or-magazine artilces. ACTIVITY 1,-1 FESOURCE PACKAGE 1-1 byradioactivityExplajmthe use detection of the such gene and instrumentsof al demonstrateradioactivity nature asof AnswerPa6cage-1-2;foithingRead-Resource questions all investigations. thenPackage in checkResourct 11=1, your per- RESOURCE"Radioactivity" PACKAGE 1-2 N. D Geigerthe electroscope,. counter, and thecloud spin- chamber, answers1-3. by using Resource Package activity""Self-test on Radio- . thariscope. k "'AnswersRESOURCE to Self- PACKAGE test" 1-3 ,ENABLING BEHAVIORAL OBJECTIVE #2: radioactiveExplainactive someradiation materials of the to dangers the'body,and radio7 of ACTIVITYAnswerformingRead .2-1 Resourcequestions .all investigations. Package"2-1, in Resource per- . active Radiation to "TheRESOURCEthe DangersHuman PACKAGE Body" of Radio-2-1.' - as a resultcellsscribeor internalof by 'either theenergy destructionexizosure, external emitted andfromof livingde- `2-3. answersPapkagd by2-2; using then,checkyvour Resdhrce Package- f "Self-testRESOURCE PACKAGE on the 2L2 radioactive "ma.te.ri-S1s.. A 'RESOURCE"PACKAGE,Body"DangersRadiatiopto of 2-3 Radioactive the Humeri t% -4- "Answers to Self -test' ENABLING BEHAVIORAL. OBJECTIVE #3: ACTIVITY 3-1 RESOURCE PACKAGE 3-1- s ,List at least eight; 0) ways Read Resour.cd P6.ckage 3-1 and :"Some Benefits of . man.that radioactiv(ty benefits _age, ansWera.byPackageanswer questions3-2; using then Resource incheck Resource your Pack- `RESOURCE PACKAGE"AnswersRadioactivity" 3-3 to Self-tesi" ENABLING BEHAVIORAL OBJECTIVE #4!Locate in current newspapers ' ACTIVITYRead Resource 4-1 Package 4-1. - RESOURCEReadings":"Suggested PACKAGE Outside 4 -1 0 orradioactivity.everydayarticles' magazines lifethat at leastisshow affected howfolsr man's (4)by -

n- I a. RESOURCE PACKAGE 1=1 ti and its R latonship to Basic 9oncepts of RADIOACTIVITY Radioactivity Nuclear Energy) e NATURAL TRANS. , . ATI AND RADIOACTIVITY 4 . - _.6 . Tile- e and tech logy 0 radioactivity ihad it scientist, Henri. Becquerel, in . beginnings in the his Pariscold, laboratory,wet winter ofmade a , left1896, a whensealed, the unexposed startling accidental photographic.discovery film plate(ste Fig. 1). Henear had aaccidentally 4 piece nf uraniumf ore': e had been expos d to Latti, he was surprised to find the' liht. ,He'felt that ___ somethingfilm darkened-as like X-rays though was it generated by tt minerals -containing uranium,AndSbon after this this, property in 1898, of uranium was givenPierre Curie and his wife, Marie the name, radioactivity. Sklodowska Curie (see Fig. 2 on next cr, page) discovered a new chemical element, J , Cr BECOERELFig.. (---"%4 ,-tadium, whose raaioactiyity proved to be four mi/liOn times that ofit Beccuerel,concluded afterthat itMmIldstudying onlythe film,have, uraniuin. However, they could hot explain why. ...____ energybeen darkened which he by_a4 unknown kind of called Radioactivity. * For-anothet.treatment of radioactivity and related concepts, examine -7- .the Nuclear Energyminidburse. Then,is mattero.gradually in 1905, Albert Einstein changing st1Bgested into energy". a'-;t'edioal,answer: "Radioactivity , (see rig. 3);. and Einsteia,f0 lated his famous mathematicalaterial property) equagon of relatingan element: the energy and the mass ,* . Energyor, =Mass E = MC2 Oneed-df Ligiat 2 where: -E = nergy; M = mass; and C = 'Speed of light. G. THE-,CURIES Fig. 2 arty (mass). aisof annatural element and torpure gradual energy changetof is called. the material prop- tivit * and this change is ,'measured in what 4 ( Curie,discoveredSoon afterward03ierre that radium. and Marie' was. ;half-life" 11. IP Z1so hiould hly no elain. why. Yor any given amount of radioactive,radioactive material, the time revired for bg, one half of Fig. 3 . - . EINSTEIN. -; that amount of material to tran0fOrm'to energy is cdkiled its half-life.* Hall-. . $ ilk Then, in 1905, Albert Einstein lives can range from fractions . . a second to hundreds of thousAnds of yeas, i . suggesfeda radical answer:,; Isk gaily"Radioactivity clianging is into matthr energy... grad.- .,.,.:..F-_, There are 92 elements, (kinds'..,of matter) OCCURRING RADIOACTIVE EIENENTS WhiCh occur in nature. .These elements, are numbered 1 (for the lightest, hydrogen) through 92 (for the heaviest, uranium). > Also, a small number of naturally rndio- Alt of the naturally occurring elements with atomic numbers greaterive isotopes ** of elements with atomic numbers less than than85 are radioactive. 83 exist , RadiumConsiderRADIOACTIVE emits radidm, DISINTEGRATIONwhat theare radioactivecalled element 4pha, beta, and gamma discovered,by the Curies. rays.' The therays nucleus are VUndles.of of the radium,atom energy and matter ithiCh originate from within Radii radidactivity_can be investigated by placing a little radium so the. the radiation' stream can be stibjected to an f in an apparatus such as that Fig. 4 shown in Fig. 4 , to its direction; the.stream of radiation ALPHA; BETA,. AND GAMMA. RAYS beta,iselectric seen and to field be separated perpendicular into amma rays. three ,parts called historically the alpha, raystheRepresenting threeby magnetic types the of separation field.deflecton.radioactive of * 'There are also a few short-lived man-made elements called transuranic i elements,difference between an element ,Look upand the.definition'of an isotope! isotope, \ Make sureyouunderstand the basic , P? whileThe so-called the'beta alpha ray isray sharply is.slightly deflected deflected in the in opposite a direeL.ion direction that (indicatingshows it to thatbe positively the beia raycharged, is - , negatively charged). -Rtmever, the gamma r y is not deflectO at all, indicating thilt it is Uncharged. Alpha'raysDESCRIPTIONS -(04 OF TIE SO-CALLED*RAYS Thethe so-called nucleus ofalpha the raysradioaCtive turn out element's to be streams called ofalpha positively Particles. charged particles In fact, an alpha from ; elementsofparticle 2 neutrons is composedexac and 2 protons of neutrons.and and 'has an. protons, electri \ y the same as the nucleus -of the element, helium, which consists t ollectivelyal charge of callednudleons.+2. The nucleus of all . The ALPHA PALIICL:.-' rig. ti hasproton_and an-elgctrioal neutron charge have-about of one thepobitive same prppertiesunit and the and neutron characteristics, (n) has no except,,thatelectrical charge. theti proton () In electricandother are words, rathercharge protons alike(quite andin like sizeneutrons having and shapeare some the andblocks building weight painted butblocks differ:inred of while the thenucleiother property blocksgip the calledare elements left HELIUM ATOM Fig. 6 Radioactiveunpainted; theelements blocks eject wouldsbe alpha quite particles alike, at differing chatacteristic only in speeds, the property called color). . l.. ., ranging frail 10,000 to 15,000 mil4 per second. -10, F ability and can be stopped by the thinnest s1 et. k. Alpha particles-(alphas). _Alphas are haveof 1 low-=penetrating metalto 4 inches).foil, or even by an ordinary sheet of paper. stopped by collisions with air molecules after travelling only from 3 to 11 cm (about . Alphas arecan resultsthey electrically from their collisionspull electrons with offair electrically--neutralmolecules. air molecules, chieflyionize responsiblethe air through for thewhich heat they libprated pass. by radioactive elements. This means that because they are charged +2, thus leaving thiismole- This tieating . Alphascules canpositively decompose charged. water and convert oxygen into ozone. a . Alphas can Alphas can produce severe skin burns. "expose" photographic plates. Beta rays i. cif Beta rays (betas) are Streams of (P) 1, electron's (negatively charged particles of about 2,000 the Mass . . . the nucleic of radioactive elements. Radioactive ekements eject(nearly beta f particles,at thea proton speed ofor light!)characteristicneutron) ejected from Betas are the sameoas cathode rays; speeds, ranging' from 60,00 to 180,000 miles per both are simply streams of fL second ability.electrons, except that betas have much greater speeds.vhd pheretore have much, greater ability of alpha particles. .411,A penetrating . .Betas Betas 1 mm of lead.havereadily More passthan through;1,00 times the-penetrating . 10 mm (14 mmcm) of of 'aluminum water -1.1.7 . Betas can "expose" photographic plates. 'Gamma rays (r) Gamma' rays' are a kind of photon. A photon is Ablincile tam of electromagnetic' .energli; visibleisduced forcefully during light violentandejected X-rays nuclearfrom .are a examplesnucleus.."eruptions" of suchin which electromagnet]. e;ther ..n a lpha p rticle or abeta particle aanta. .Gammas are pro- . Gammas haveare invisiblethe same and have far greater penetrating speed as visible light or X -rays (186,000 miles per second in a liaCtitym). ., , ability than even X-rays. . . Gammas can-;timps! "expose" thatGammas photographic of haVealpha morerays, plates.than 100 titles. the penetratingability of beta rays, and more than 10,000 . , Gammas-readily penetrate up to 25.4 cm.(10 inches) of lead? $'Gammas. Gammas can canhavekill prodtce abacteria greater severe andcauterizing otherflesh microorganitms:burns, ("killing") effect upon unhealthy tissue than upon healthy cancertissue. and certain skin infections. It is ,this property of gamma rays that makes, radium so valuable in the treatment of - GENERAL PROPERTIES OF RADIOACTIVE ELEMENTS form of visible light. Such . All mentsfact,insubstances ve can ryit causesmallis can just certainquantitiesbe suchse&I aotherin mixture tothe substanceszinc dark which sulfide, since is radioactive to.fluoresce. theyused can l'gloreoncause clock elements or and emit energy, some of whidh may be the zinc sulfide to glow in the dark.ForphdOhoresce. example, aAlso, radium radioactive cbmpound,watch addedele- hands to ,make them visible in In the dark. , 4.Radioactive elements,canA radioactive react element with tendslight-sensitive to ionize the air near it. emulsions (photOgraphic film) even if the containers. . emulsionsRadiation/from are well a radioactivewrapped in their'usualelement can heavykill plants,black paper seeds, bacteria,-and eve %ft , animals (includ- METHODS OF DETECTING RADIOACTIVE 'RADIATION ing uiah) under certain conditions. instrumentsSeveral instruments are disbussed have beenbelow: of importance in detecting t and measuring radioactivity. .-. Sixq6) of these 1) Thetosityisbased.onthefactthatradioactiveemissionswillcausellhecharge firstchange is (see the Fig,gold 7).leaf on the When electrically charged,electroscope..,The the gold leaves detection and wasurement of radioactive inten- the greater t0e,4 electroscope of-thesityseparation,separation. electroscope and kind when 'of separate;subjected radiation,cunbe theto agreater radioactive tested. the charge,source, the. source By observing the rate of change and-direction of leaf inten- 4( 2) ' grate (see Fig. 8 onparticles43%The nextlived seconda cloudpage). from andis chambei 1869 theof manycloudto (invented199)'; other cha mber.weparticles byare the able American, produced to observe C.wheh T. the nucleiR. pathsWilson, disinte- of whoalpha ByIn m theeans original of the condensation'track apparatus,,t4e Gold Leaf. -13- ELECTROSCOPE Fig. 7 'rubber bulb, or lower part, is filled with water ti volt,theratusdyed radioactivepotentialblack. is made isof materialmaintlidedglass and being containsacross studied. the a sampleobser- of The upper compartment of the appa- A 1Q0- .+, 'vation spacewaterhydrogengas in above Vapor.th' isthe .Theni compressed4 blac a u4when the bulb is oartment.theer becomebulb is 'eaturated 'squeeied, with the The,*ydrogen 8AdioactiveMaterial Particle Tracks waterHydrogensaturated vapOr gas with bseriationbecbmisnextleft released, supersatuiatedby space alpha thellydroggpxpands,(a particles black with background canwater now vapor; be cools,is seen pro .andin the Tracks - more100 volts or , tracksoningionize the some are someof like- theof the supersaturatedfog hydr-a-g- streams which'appear v to shErgt, hydrogeny molecules.. The alpha part_ 'the alpha pariicles les, thus caus- nse black dyecontaining rial,.out from the exposed ttp.of the radioactive mate- - 11 1Rnbbee.r-Jni14- 3) whichAnotheris-by(on is nettmeansmethod inserted page) of for the throughyoudetecting deiger will -an dotice,,acounter. alpha.and insulator metal bete' into wire, raysthe A, In Fig: 9 WILSON CLOUD CHAMBER Fig. 8 metal2,000are connectedcylinder, volts, toC. a high voltage source .(about which is not quite high enough to The wire and the cylinder "N. alphaitcause acts, or a 'a sparkas beta a "trigger" toparticle jump between andpasses causes-the Athrough and C). Geigerthe tube, If an ,' jumptocounter increasebetWeen to discharge;i.e., Athe and sound C. of the causes spark .a so'that spark.to. a The amplifier is used only ' -14- crackling noise' may, begyllinly heard in .indicatingemission.isthe the used,headset presence.of insteaTO.a,headset), (sometimes a radloaeave a loud speaker thus, T. 4) emulsionThealphasto photographicdetect and,of,a such etas chargemethod --particles also may be as used otographic plate placed, 'nee they affect the tracksthesgemulsion(em oftracks, theseis made scientistsparticles visible. throughare they,flightable the to paths. n) is devploped, the actual When the film By measuring Fig. 9 rifetime,asdetermine velocity, range,L--andsuch momentum, phrticle the mass, characteristics like. charge, And the 4 GEIGER-MULLER COUNTER mannerwill,raffectchestthephotographic uncharged similaFX-ray photographicphotographs. methodtogammas, that can ofsince betheemulsion.in used theycommon` toalso detect a . 5) heatedvolatileTheresearch bubble to liquids temperatures laboratories.chamber (liquids method above whichis theira change respective readily boiling to vapor) points. Bubb hambers arebeyondre recent the method scope of of particle our laboratory, detection for they which are under pressure and which are These tracksParticles are photographed passing through fOr the and is used mostly in utilize 6) ,study and bubbleanalySis,The spinthariscope chamber just leaye as are methodtracks wascomposed much usedof a inseries earlier of bubbles.days of particle pha'ographic-emulsion tracks. research, but is little used and a magnifying glass. Wherevernow.flash of charged light servesparticles as astrike detector. the screen, a momentary flashThis of method light utilizesis produced; a zinc thus sulfide screen, radioactive material, By counting the flashes per unit time, one can also deter- ,. the mine radiation intensity. . -15- IN STIGATION NO. DETECTING AND NFASURINC THE PENLIRATING ABILITY OF RADIOACTIVE RADIATION G". Purposes: , 1) To investigate the effect=of radioactivg materials on an electroscope ar41on a Geiger counter. , , '2) To investigate the pciltrating ' abilitythrough -of aluminum,,-aad: bets radiation through (in air,'14ad).. through cardboard, , .-r t Materials Needed: . . Simple electroscope;-cat's fur; hard rubber stop watch or watch with second hand;dial; Geiger uranium counter compound tube qr andraciiiolCtive,isotope; a#0c-pitec apparatus; 20 cardboardradioactive sheets, sample; 4 inches wrist .squarewatch with and illuminated1/32 inch . - thick; 15 aluminum sheets, 4 inches square and 1n2 inch thick; and 15 lead sheets, 4 inches square I - and 1/32 iYrch thick. ' e' t . , HofYou the atoms of radila-CtiVe elements resultshave*learned )in 'emission'of-alpha in this study of this4minpicourse that the spontaneous disintegration of the nuclei . . . particles, beta particles, and gamma . . bytheelecttesCoge,rays. Geiger Counter, or.Olher method as previously described.ThiS. emission'isAiled radioactivity or radioactive radiation. Such emissions can be detected Because alpha parti -'. . - , -cies ionize the gas molecules inthe,air.and canthereby:discharge an electroscope, their penetOting ---.. .- + . .. . gammaability rays is notcan greatbe detected enough by.)theto-iffeco.a Geiger Geiger counter countertube. tube i N -; On thd other hand,' beta particles and - -16;- penetratingIn this investigation ability of youbeta will'examine particles. some effects of several radioactive materials, including the. Procedure: 1)' Charge an electrdscope by rubbing a hard rubber rod with cat's fur and then holding the charged Fig.chargefingerrod near10, onwill below)thethe be knogiland left of not9n the theholding-the electroscope. electroscope. charged, rod. At the "same time, totch_thg-electroscopeThis process is called charging by induction Then, withdraw the charged rod. knob with Aa residual (see

ElectroscopeUncharged. bynegatively, induction chargedLeaves repelledElec&nsBodyfinger intovia ElectroScopefiniterelectronsdeficient is.- -.when in whenelectroscopePositively rod 4charged THE STEPS IN CHARGING AN f T"-- ELECTROSCOPE BY INDUCTION removed removed -17- (2, electroscope.electroscopeleavedObserve4 collapse. the'rate-of in the samedischarge manner of and the place electroscope, a radioactive as evidencedseSupie beneath by,the therate leaves at which of thethe Do you Observe a different rateObserve of discharge? the collapse over a,pericii of:several minutes.' Now recharge the .0 -Setup,the Geigef(a) On.a counter sheet at'apparatds;'Count notebook and record the background 9:ickse Number. ,.f'beckground clicks (tiverag/minu: paper (please, riot in:this .book), enter'the following: Background Reading (b) Place thiaradioactive sample'at thecounter distance nitt!er.scale. which gives a maximum reading on the 'Geiger Record this meter value: Maxinium Meter Reading (c). radioactiveUsing an illuminated sample, above. watch .Recorddial, place this themeter dialoatieiactly value .for the the watch distance used Dial. Reading for the (d) Using a radioactive isotoges_place i - atethe same dance used above, Record this meter . . value: . Isotope Reading,-. . (e),Write down any inferences or conclusions you can draw from the recorded meter values of(b), (c) , a and (d) above. Placea(a) Determine radioactive nd.repord sample thatthecount emits in beta a-data particles table such'.2 inches Is the from one the shown Geiger on cZ5unterthe next tubs.page. 1 (b) P1 the same samplq,4 inches from.the counter tube. -L8 -. Determine and record the count. reachedContinue a.di'stance moving.the ofsample 20 inches away fromfrom the counter the counter tube. tube in 2-inch intervals.until.you have Record the count for each 2-inch interval. (Plpse do not -write on this page) SAMPLE. DATA TABLE 0 Distance . Count . - ,.. Distance Count: Distance '. Count . / (Inches) . . 10 -18- ,44 12. . 20 . 8. 1614 22 z. 4), Plot a curve of the table data, usingvalue. Then see if you can answer these "questions distance as the X a s value and / /- (ReMOmberothat the recorded counts /, count.as the .Y axis include background(b)(a) wha,tRow count):far type can of a radioactivebeta particle radiation travel reaches 4-- through air,beforYbeing.absorbed?the counter tube after the betas have been absorbed? \ he counter tube to obtain a maximum reading on 5 ,-Pla.ce the betweencounterradioactivedothe not meter. thetubes.write samplesample in Aecord this' closeand thebook!)-.the enough counter to tube; Retord this count in a data table such as count reading. Now place one sh'et of cardboafd recaidingContinue the °w ittoplace reading,after addi4ional sheets of the one shown on the next between the sample and-the pagee(Pleasecardboard of each sheet. 4 Use a total of 20 sheets of cardboard. aluminum_iaiead of cardboard. , Take readings , whenandRepeat 1,the 2,.3, theradioactive investigation,4, 5,'%6, sample. 7, 10, but 12 us e'sheets, and of 15 sheets of aluminum are placed . between the counter.. Repeat the cardboard sheet inves ation once more, -but use sheets. of -19-- t -.9k7 lead.thiS-time. A I 4 . . . .(Please do not write on this page) SAMPLE ---i- DATA i .kBLE : '440. Sheets -' Count' OARDBOARb No Sneess Count No ALUMINUMsheets 6unt No Sheets LEAD *7 count " \ `1. 0-f2 .121311 0 -0 2i . a 43 15 4 . "" 3, . ' 65...... 1716 .. 6.5 , 6 .---.2..., 7 19IS- . , 1O 7 .15 12 7 *Plotdifferentof the aurves.q variousmate;ials coIo onithe X axis and the' respective ; these data don pencil4 the same to sheetconstruct of coordinate_paper, a graph for each of these count readings as, the Y axis.' Use threeplacing absorber the rfumber'of materials. sheets 1)By infere pes fr m these graphs, answerfadiatir?What the tfollowing ickneslof cardboard, aluminum,\\, and lead produced ! questions: complete absorption of beta Which of "thfee,absorbers was moSt4effectIve As e . an absorber of -beta radiation? {OP Of 40 Purposes: 1)'To construct a simpleINVESTIGATION clotld NO 2: MAKINGI.AND USING A CLOUD OHA19ER TO TRACK ALPHA PARTICLES ;-chamber. , 2) To-arse thec1ntid chamber to See alpha particle -20- tracks. ANN / Materials Needed: N1) one-pint wi outh vacuum bottle' 10) two pg ds of dry ice 2"papa small diameter r bag blo oves r brass disc, any 14)13)12)-an11) soldering hammerone old 5" radiuM.1 iron dial Watch or:tubing, clock. ou gth of copper' water idepipe diameter or 3/4" to 1" Lucitetintweezers'thickness snips .or ple 8" to 1/4" hisigl ss 4" 3(4", and 18)17)16)15) 2"x3"solderingpiece to2".' 4"of slidediameter silkflux, projector solder clear plasticor bright food dish flashlight 'Introduction it Prwiew clp 1 black pa n er detection by reading the section on the detection 19) on pint of denatured alcohol of radioactive 4 materialsProcedure: and radioaCtive (If yout,-instrIcto tion presentedhas a:earlier c loud chamber,in this minskip Sectio A oUrse. and go directl y'to Section B.) ; A.: C nstruction of A Clo d , melt a hole tudythrough Fig. the 11 plastic (seene capt page). o ,the va Chailtber- e Then- at t piece of copperum bottle. pipe oetu bing and use it to If cork granules end up in the. 'foodhollowCop dish. surface cap, OfSoldetshakethe the, thedis coppe out. .Now'a reheat duul 1 black.the pip \ disk tothe end of andimelt a hole inrthee piece ceder of the plastic of cop0r water pipe; Paint the then 'throughNext,to, thefitpush. just Cl, the pipe holetoinside which it thAcap. of dish,aoldered strip ofthe blotting disk thr pa Naw.your'cloud ch er s hoIt oufld regemble.Fig.: n the disk andand make a ring of .it IL ofFutonUsing dry aiceyour cloud into gloves. Chamberthet vacuum to, bott-e....,Se -/ With th hammer,1pha Particle, break the TraCks dry ice into 1 /2" lumps Slowly pour alcohol 8Ver tie- Wraps. 4 .../ - . and placeAt these first,.there lumps Will thatbe a-violent o boiling; the dry`\ice'.(about 103° F. below zero) .l?ut this will subside when the, temperature of the aledhol ,droph td . Gradually iidd more alcohol un 1 the flask e , ..., SolSisin filled the ,coo.112'1 ling om iixtire the top. he blotef sect' paper ring in alcohol and position it as shown in Fig.. 11. Putt \ plastic cap on the bottle; the copper pipe she-tad-be 4 Using tweezers, , -'.' chartheplac 'disk"e, o w' h the square of Lucite 6r plexitlass. a static electricity and to cle n of the radium watch -or cloCkdial (or clock hand) on the ,§..., the viewing region of any Rub thee square with silk to give it a ions. blackdisk. 4 Cover sourceClear-Plastic Radium clock hand. or dial.1,ucite (rub with OUre silk) Blotting paper ring/ CO Black painted'eepper disk Denatured alcohol 2" diameter sy. ' / Illuminateas you look the down chathber through from the side orradium,clockthe top, you will dial see and the crosAtng tracks the disk. with the projector or.flashlight. of alpha partieles.coming.out of ':Your cloud chamber will After,a few minutes, dayscontinuetheIf7you Section'you see tomay operateoftracks have the to piecethat recharge do not the originate cover every to many hours without any from the radiuut_source, they will fifteen minutesfurther by attention. (Remember tbat-on damping it.) probably be cosmic nucleusrays. of an air molecule, such as Ii-ybu see a'fc/ikedtrack, this indicates nitro ens, that an alp a particle has . collideclvith the Usual Track 0 o e Collision Tracks 'ft -- 0 0 - Q. Makeinstruct-or. drawings of your. observations (iden and turn them 00. your RADIOACTIVEThe spontaneous DECOMPOSITION change of tlie into lighter nuclei., (into otfter elements) decayis called emits radioactive-decomposition. either- alpha particles or ft botaIn pareidles-,er_both. radioactive deeomposItion Man caft\do.little about the radioactiveundergoinr. .723- asdeday you process--heshall see later, cannot it stop is nowit; possibleand untll.the to create turn radicacciveof this century, auc10. he artificialty. could not start it. However, -The-rateHALF at LIFE' which radioactive decay 'occurs 1s'fixed for each particulml: kind of radioactive nucleus, - sampleand n6thing of radium can be atoms done towill change have thisdecayed rate atto theany endnoticeable of 1,620 -,-:-tent. years, and half of the remaining atos For example, one4,t, half of-a given willof adecay specific during radioactive the next-1,620 nuclei years, will decayetc. is called the Aalf _ . The length of time during which half of a given-number . v. life'l that radioactive element. . 4 i '' _. P . the half life_is math maticallY related to the 13,4rEicufar --. element by the following equation: where /_'is the decay constant sy 2 and ty7 ist1/271.= the half0.693 life symbol. symbolLet us.see for how this equat3 can be us4d to calculate decay rate. the element`, radium. .The 226 represents the atomic mass units First consider(atomic weight), and is equal 226 Ra `Ra is the to the sumnumber of "ye'protOrisof protons and neutrons in the in-the-radiumradium nucleus. nucleus. - TheI fife'(#' radium is known tol4e 1,620 years, The B8, is the atomic number and is equal which we will convert to seconds. c -24- 7 4/6 0.693 . By the simple operation of division o both sides of the quation by tt, write , = 0.6 3 as t k 4 tAltk _ 0.693 ) t . ' 0.693 t1/2 Then 4 0.693 = 1,6201.36 yrsx 10 x 365 daysiyx 86,4001sec/day 1141sec This means that since 1 gram of radium contains 2.665 x 10 21 ,' nuclei,4 a AP This is over 31/2 billion "counts" or disintegrations per '2.665 x 1021 nuclei x 1.36 x 10711// nucleardisintegrations/sec = 3.62 x secolid! 101 nuclei/sec has anmaterialThe approximate common which measurement radioactivityproduces fOr 3.70 radioactivity ofx 101 Curie?. is the Curie. 10 disintegrations per second. One Curie is that quantity of a radioactive Can you see that one gram of radium RADIOACTIVEIt(by was ejectingRutherford SERIES alpha' and some or betaof his particles), co-workers ther...i\ho remaining discovered atom thatis sM1 when radioactive one..radioac,tived and may atomsooner disintegrates or. later -eject another particle to become still a different atom. This radioactive decay process was found to . . continueand, not throu radioactive. &h a series of :elements, ending up finally with a type,of atom that was- lighter, stable, / , ..,-,.. 4nThere ÷ 2 areseries. four commonly knows radioactive series. The only change in mass number possible in this -seriip is,eith -,7 I,. . One of these starts wiih'4-1°V - 9. zero or -4;and all is called the ' the elements- in this series will have mass numbers-which -diffezZom 238 by some multiple of 4 ----,., .. f .. -__._ . see Fig. l2t. Thereon next are-three page). other natural series. One of these starts with itI 0 ''..."..S...... 235 - 92Ra and, is t4lied -the uranium-actinium gl',, series, or 4n -I- 3 series. Another wit* 232 90 - Th. as the starting member is called the Thorium, y 241 " -% . . or 4N series. The .last series, the Neptunium series, starting with plutonium, . . - , 94 ' / The only membei of this last series found in nature in appreciable quantitie6 is the Stable and f1ial,Kproduct, , bismuth, 209 . 83 Bi. -26- O .(a)

uranium(1) .Thorium(UX1) flum II 4.5 billion 241 days. n_ ''-'',000 years years (23* Protractinium 6.7'hours Ca)

ThoriOm 04;4. Polonipm(RaA Radium Radon 82 000 years 3.05 minutes . 1520 years 3.82 days 1. 0 I (3)

02.0 Lead(ria6) Bfismuth( RaC) . .onum(RaC1)(20 Lead(RaD) 26.8 minutes 19.7 minutes .00016 seconds 22 years

(a) (d)

(Ade.? eismuth(RaE) Polonium °,4 Lead . 5,0 days 139 day6 stable.,

*I Fig. 12 CHIEF MEMBERS OF THE URANIUM- RADIUM ,FAMILY (411 ±2 Series)

Showing (.1) half-life periods, (2) atomcmass numbers, and (3) atomic numbers. ?ratans are repreaented by,a + and neutrons by a ±,sa that you can see where particles come from and so. that conservation of charge isnot violated. The -etashows alpha partibles (oC) as helium nuclei (beinggiven off) and -beta particles (A) as electrons (e) coming fromthe nucleus.(due to the integration of neutraps).. Gamma rays are.also given off duringmost of the transformationa, but are not'shown'in the diagram. 31 -27- FOR THOSE WHO WANT TO KNOW MORE: energy.The nucleons inside the nucleus of an Isotope* have large amounts of stored elfctrital Think of two protons and two neutrons forming.the;singie nuclear unit calked the alphaparti- -RADIOACTIVE DISINTEGRATION BY ALPHA PARTICLE EMISSION and nuclear. en ugh energy to be ablee, and to considerescape from thii the unit larger as a nucleus.stAkunit of a large nucleus. Generally, for a len picture this sub-unit as acquiring nucleus, escape is a - largerate numbers in terms of nuclei, of half welife.. can determineThe time required a constant-rate for event;any given of and disintegration isotopeit is impossible -to disintegrate W to predict to halfexactly its.orig when such an event will occur. We have expressed thig .\ But with really linal,valueEnergy is call releases d its byhalf radioactive life, just disintegration-derives from the change of masses'of the particles.. , as we learned in a previous section. For example,k 4 I 226 222 4 \ 88- Ram 86 Rn+ He + Q 2 . where lepredents tie radium nucleus;-2 and Rn representsHe representsthe . the alpha particle-Q .41 represents the energy liberated in the disintegration process; i ter, radioactive nucleus produced by tile Anits isotope weight is (mass) an.element varies, having but ina nogiven way numberis its ofchemi protons al behavior but having changed. different neutron numbers; thus .-- f -2 ° nuclear mass. \ disintegration.From a. table o he6mic mass.units, the mass. elemenCievriadon):-Toca/taate Q, one of Ra ='226.10309 AEU must,calc-Olato the change-in and the mass of Rn .= 222.09397 AMU. 4 .equationAlsok.the withmass o and yieldsHe Rnis +given He + asQ-on 4.00388 AMU. the right side,---sat-shown So the nuelearreaction below: starts on tho left side of the a o 4 / Notice .that Rn 4 = 222.09397 AMU + tit-nucleus, Ra, and the two 4.00388 = 226.09785 AMU, daughter nuclei, Therefore, the mass differencebetween the ma0 ss -valu - s of the pa 226.10309 AMU - 4".04785 AMU. 0.010525 AMU, which .can0 be converted . to Thisenergy mass ifference between he equation; arent and daughter Mev. nuclei =. Q4= re, Q (in: Nev) = . 4.1378.-Nev0.00524 (nearly 5, U on 931 Nev/AEU. electron volts) .4" / DISINT4GRATION-OF BETA PARTICLE EM7 SION number m st docrease, since a neutron-minus an electron resqp in a,proton! he resultantisotope nucleus disintegrates increases byby one,emission while of a beta particle (by electron 'eelction), the e mass number remains uncharged. For example, the The sotop bismuth 210 emits ebeta,aarticle according to the nuclear reaction:. .210 83 84/0 Po 4- Q 4 Totoa'and support this,dea of beta decay, yo lectron, with'he proton remaiing.in the might imagine a neutron in the nucleus being split into a pro- nucl4 and thelelectron ejected from it. There-is j s ones... problem with this simple notion, the released energ . . Q is observed to be not always . the same. Mx account for a continuous distribution of energy Q (due to continuous distribUtion of i . ' velocities among the beta particles until a maximum velocity known as the end point velocity is reached), .tI / particlesit was suggested are-emltted in 1931in.beta by Wolfdecay. " yang Pauli that this difficulty couldbe resolved by assuming; that two One particle was an electron, and the other was a then unknown The total energy Q could thus be shared by the toelectrontype the of maximump and t end point ve ocity. ticle which later was called thy_ neutrino. neutrino, a d various combinations of shared energy The equation for this is as follows: Auld yield various velocities up (neutron) N (in nucleus)---*P + (proton) 1.1 (in nucleus) + particle beta: d7 + neutrino 4'...- . discovered in 1956. . The neutrino has no charge and very little Mass. It e neutrino was finallyI sses much energy, so it moves very-near the speed ./ ofilight. Therefore it has tremendous pene- _tr,tidg ability.pos , so iong.tght it would It bias been calculated that to stop an average take the fastest neutrino about 50,000 years to go from one neutrino,..a block of lead would d to-the have Many natutally stable nuclei, when * bombgrded by high-speed particles, canARTIFICIAL'RADIDACTIVITY be transformed into different som times such bombardmentclei. ZP These kinds man-made nuclear transformationsresults are in'the formation of unstable accomEanied by nuclear disintegration,nuclei. The bombarding particles are and ofte 1.\ Fission - the splitting of a heavy 6, ptotons, deuteronsor neutrons. nucleus into two lighter nuclei;Man-inddced nucieer transformationg inlude: some-of these fission Aproducts are radioactive.areaF radioactive. combining; light nuclei to form a heavier nucleUs;- some of-theSp',fusion products 14aO-MaddttanSmutation.of0 One element into another:was'first ,3 \ 4He accomplished by Lord Rutherford in 1919 -A on the next page.by, bombarding nitron (7 ) with alpha particles nitrogen (2 ) This nuclear reaction is shown - A. 14N. 7 . 4..4ke 2 17,0 8. -1H Noticesimilar tfiat to Rutherford's, it is possible-to produce many isotopic forms of an element, most of which are the trasmutation changes nirog&t-14 to oxygen- a stable form of oxygen. By processes (. unstable.guish . theft' from the-natdrally occurring radioactive ones.These man-created unstable elementi are called artificial radioactive elements, to distir- As an,example,.when ordinary phosphorous . ( 153 --P1 Us-hit by a fast-moving - deuteron:* -*( H),_the follow ' 2 i g reaction occurs: k 1. .," 31 2 H ----4- - 32 -- 1 H The .3 15 'Tr nucleus is15 unstable and decomposes,P + emitting ;a beta particle and forming stable sulfur, 16:1 15 P + 1 . N> -15 32 p --.. -1 OA + 1632 Artificiallyand research radioactive laboratories. isotopes, such\as 1532 P, are commercially available are used widely in medical d * Deutelquni-a car is "heavy hydrogen," deiieeiOn. - 1 an 'isOtope ordinary hydrogen c3i1 , and its nucleas is called ".1 --.... , ' tli -Another radiOactive.isotope,. 14 6 C, is being commercially. roduced in large quantities by\Tea,n6 of neutron 1n0 ) bOmbardment,.4 shown below: - . .. 14- 7 + .1n 0 14C-6 + . 1 /- ._ sion of a beta particle. Carbon 14 has a half life Of 5,360 years and , . You might iash to read more about4how decomposes -with the'e . archeologists, geoiogi ts, . Ca on14 .is usedanthropologists, in the dating and other scientists use the carbon-14 dating . of artifacts. .. technique to determine'the approximate --., age of some artifact.--Ask your teacher or librariandfor some references. V In some beta reactions, the nucleus:,i. expels a positrone . . ., + 'A*. ) rather, h n an electron. Ih such/a. nucleus, . - , ' '' l' . / + ,2 Cx? apioton(lOcharigesint6aneutron 1 0 pluaa po4ltron (e ). and r neutrino.. (-Ff. .i :i In the reaction, itthe loSeS transmuting a proton nucleus and gains change a neutron. to the nucleus-of.the next lowest element The general,reaction,,is written as follows, where ;X is the on:the periOdlx table, because r original nucleus and Y is the next lower-orderedl nucleus formed by the reaction: (At." Mail - Neutrino.:L v . The---- positron ---- i s luite like an electron negaeron , except that it has a:posit Ve electric chaI'ge'./ L33- A typical\reactj.on is the decay of carbbt=1-1- catomic number 6) to boron-11 (atomic umber 5 , as shown: / / 11\; 11 5\eB ---'4.may be of interest\to you thatthan-raade. almost two-thirds of it o the isotopic forms of tthe elements ar , 1

C g SELF. TEST ON TES p Comaetion: 1.° Radioactivity was discovered by 2. In 1905 Albert EinsL in suggested that . 0 4.3. Radium,In radioactivity diSintegrates, We have .-an d*ample of iving Off , and Answer tbeyfolrowiag: Give at least thrde methods Por r degcting padioactive radiation. G.CO. 7.*8.\,How How oss does an aalpha gamma particle ray differ differ from fromalpha'andWhatWhat a betais*trapsmutation? beta particle? Aticles? 10: 9. WhatWhat is is a meantOprie? by hal,Il lfa? A 13.,,What12.11. is.an isotope? What iswould a neutrino? it 14,, 5. NameWhat andi& tadioactivity?discuss briefly-two basic,, processes for obtaining energy from nuclei 4 SWERS TO SELF RESOURCE pCKAGE 1-3 TES4 ON" RADIOACTIVITY ,1. Henri Becquerel. ' 4 4:3. MattertransMutitalpha gradudllyparticles, changing.to be a.particles energy. and gamma rays. .5. (5)(1) spinthariscopegold leaf electroseope, (2) cloudeohaTber, (3) Geigacco 2 (6) b ble-chrle and d (7) spark chamber. raphic emulsion, - numberTransmutation, of protons is in the the change nucleus. of 'one element into another, and 1t results r 1- gm a change in the Alpha (negativelyparticles are charged p6sitively particles). charged partlidles '(helium nuclei); beta particles are 6 L- 1, areGammarays. charged like areand non-aresuper-energetic -charged, particle electromagnetic-energies-like X-rays) in naturR. and are bAsically (photons), wave-like similar in nature;in. nature alpha to andX-rays beta radiations gleptrons 0% ,- 10. matttialhalf life is the length of time during which half of a Alien vi'l1 decay. - amount of a specific radioaCtive I ) A zietol'inoperCurie second. is the qqaritit . a particle having° very Tittle 0f radioactive material which ,produces 43.70 no possesse*- so. much en` gy .1010 disintegrations., 12. Toit stop-(photons) moves an. very average50,006 'nearly neutalno,years-to .at. the go yoAspeed from would of one light;eed a itblock is -a-productof lead so cilong that 'it 'would take light -. is nd of the block to the other:: mass, t"' eta particle dealK 4. ,/ 13. faithAn isotope different is oneatomic masses. two or more forms of atoms (elements) with the same atomic number,'but . 15.14. NuclearRadioactivity.isin this energy process is thereleasedmatter process is when gradually by matterswhiCh transformedmatter\gradually changes to intoenergy. energy.changes into a,lighter'form of matter; This is accomplished . . a by anatom- splitting Process called fission, or .by an -atop- fusing process called fusion. t

Air

*V -38- la 1. RESOURCE PACKAGE 2-1 RADIATIO 0 THE DANGERS OF RADIOACTIVE TO THE HUMAN BODY body, which will be signif7 1 icantIn this in section,the study youmwili of be introduced to some Vb. radiation damage. of the biology of the h In.terms of humane body weight, about 607. is due to water and about 40% is due, to the lighter elements. bones, etc. The (Seebody Fig.is built 1), Theup ofcells'are cells and organized successively into unreplaced throughout life; whereas other cells are cellular products; it contains blood fluids, minerals tissues, organs, and body systems. coistantif-being_rep Some cells ced. Cells.arealimentqry stable which and tract,require remain etc.replaceMent include blood cells,-reproductive ce4s, skin -) - 1 cells, cells lining the As statedtion of above, the total the bodyfunction'of is organized the whole body. into organandstissues,-each of which There is, therefore, an interdependence of organs carries'out only a por-. and ful)related effect tissues; on'the damage others. to one of the body components can (and . Usually does) have a deleterlpus (harm- one from the-male (Spermatozoon) . -ormLf4!!!!ttike . of-uflls Humantiatedfemale reproduction cellS,(ovum). then iAlterresults in differentiationthis from union the union of .cell masses (fertilizatiOn),y1 period of growth results into organs and tissues; and a mass of undifferen-tally` into tie young (irganisft (fetus) itself. -39- Le-45 of eye Thyren Lu7955pieer af-ft ey s tYri Ovn Teste (me /e) Gast-r.o-r1-Atestr s Fig. 1 SOME BODY ORGANS Ity4 inJC. (Magnified several hundred thousand times) A CELL, which enables, it to counter the presence of substances The eratelyforbody system or accidentally has an immunological introduced. character, to itself, whether these aiK-invadiug lw organisms or some foreign mmterial which has been It is an established fact that materials till undergo Material andsome_damage the amount or ofalteration radiation; if they pre irradiated,In contrast to the withmostly*ofnuclear .the reacitons chemical resultingcompounds. from bombarded elements, as degree of damage depending upon the' Such compounds cansuffer chew cal alteration if discussed previously, living organisms consist irradiated. anning is thea common suni. example of chemical alteration of body tissue (skin) due to irradiation (ultraviolet rays RADIATIOWDAMAGE. TO THE gMAN BODY AND BODY SYSTEMS . effects with which we will mostly concern ourselves Radiationsuchare those"inanimate" can on affectcells structures andall bodyparts asfluids. of..thh tendons, body, bones, but andthe -the For our introductory purposes, we_will ignore like. radiation.damage to . categories: (1) direct action and cay indirect action.The mechanism of radiation damage falls into two main ...,- ... Direct actionAction 'is the disruption of some part of the stricture of the cell by the action of the bombard- , 4 4 ing sdiatiOn. Damage may be general damage, upstfing to a_greater or lesser, the overall activity of the cell. On the other hand, damage myoccx.::- only to a part of'a-cell which has' a spe damagedcific function;by direct-action for example, radiation, a gene. the part is called a target and the theory which treats radiati When a specific-body structure, such ad-a cell part, is directly . damagesoonthought learnedas thatbeing thatthe caused Targetindirect by Theoryhitting action might the can relevantalsoaccount be.a targetfor source all is radiatior-inducedof called damas:t. "Target Theory." damage id the body, but,citwas It was initially -In indirectIndirect action, Action no part of the cell structure is damaged.directly; but-extremely chemically active bewhichgroups used eventually toof showatoms how disrupt(called free-radicals the free body radiCalp canfunetions. be,fOrmed: are formed by the radiation process. In the ionization of, water, the following equation can It is these free radicals where the OR- and Ift are ions. H2O --> fl + OH - reaction,By a more complex process than the simple dissociation, ionizing radiation can produce in water the k * An ion is an atE?m. or molecul.e which has become electrically charged. H2O H + OH The two products on the right, above, are not the rel ively inactiveSuch chemically ions - active the first freeequation, radicals but enter ,vigorouslydisruptionareuncharged, into ofcombination somehighly cell chemically-actiVe withfunction. nearby molecules; free radicals. and if a molecule is past of a cell, the result is Wheregen peroxideoxygen is and present, the free the radical,,H effect qf ionizing radiatfon.is increased, due to the formation'of hydro- C The cells-in the human body are interdependent. RADIATION .DAMAGE TO REHOTE SITES A' principal connecting link between all cells is the bloods which supplies cells ti withfood, oxygen, and other chemicalg while carrying away carbon dio: :ide, nitrogenous waste, etc. amount greitlytionsIn some can upset.cases, be very the large. overall effect on the body due to a slight Another example4 if blood-forming tissue's .temporarily cease to function, the oxygen For examptutf-an endocrine gland is even slightly altered, the body can be' variatli...ad1he of certain secri. ent.supply organs. to all body parts can be cut off; and this, of course, can cause other malfunctions So you can see: that radiation damage at a local site, either direct or indirect, may of/differ /, distance." affect body parts remote from.the irradiated area. This process is sometimes called "action at a -43- 'MORE ON RADIATION DAMAGE- TO CELLS SomaticRadiation Damage damage to cells is often classified as somatic dataGe And as genetic damage,' Jok, -divideSomatica while,normally, damage but butlateris damagenot on the may which ability resume affects tonormal reprOduce). cell activities. functions, such ac cell division (the ability In somati... damage, the cell may cease divisior for Ora cell to . Genetic-damageGeneticreproduce Damage offspring is damagto which theare characteristicgenes of the parent cell. within cells which causes impairment in the cell's ability to In organisms, genetic damage results - in inability to reproduce offspring which are characteristic.of the parents. I -MORE ON RADIATION DAMAGE TO THE HUMAN BODY-. I) Radiationand takes damage2. to, the human body includes direct and indirect-radiation damage to individual ctlls account the phenomenon of action at a distance. This radiation damage may be somatic ofand/or just geneto a ic;cell. only in this case the definitions alreadygiven must refer to V the,Lhole body instead Excessive radiation exposure affects the body in several ways:' 1). Radiation sickness is producedresults by'a in massivenausea, vomiting,overdasepf diarrhea, penetrating low resistance external ta-:infection.,.andradiation; and it. hemorrhages. and- possiblydeath. ,1 2) Radiation injury consists:lesions. of localized radiatigon effects, such as*burns, lass of hair, and skin Genetic damage is also a.form of radiation injury. . - . 3) Radiation poisoning resultscan from result the entrancein anemia of and radioc.ctiVe cancer. materials intOjhe body, and4t' , r 1 Obviously,(2).internal an individual radiation. can be harmed by radiation by two different means: , (1) external radiation end GO Externalrange,External high Raiation radix penetrating,external ion can be categorized radiation into: and (2) (1) long- short- 4, range, less penetratitig,external* radiation:. In case of the long-range type, the rays originate from , rayssomesome areradiOactive'materials depth highly before energetic doing damageand outside penetrate to oftissues. the the body. bady to The - EXTERNAL RADIATION Fig. 2 Notice-depths in in Fig. the 2body that, before the rays.comespending totheir thei energies. man from the radioactive source. Also, notice that a large portion of the radiation Rays penetrate to different . I . passesInternal through Radiation the man's body without stopping. breathed.In handling radioactive material, it is possible that the materill may become airborne where it car. be Special precautiohs should betaken against this ever happening. Therefore, all radioactive material If radioactive material should get into your mouth and be swallowed, this could be fatal. , must be ,candled so as not to get it on your hands or into your nose or mouth (see Fig. 3 on next page). INNUNOLOGICAL E..1t.CTS 741t OF RADIATION reasonquantityIf foreign for is this proteininjected shock is again, isinjected that a insevere "nto response thereaction body, to substances willal.first occur; nothingCalled this anti,reachappens. ion is known as mrotein shock. If a few days later a small The withthe thebody protein has made antigens protective of the substances second injection, called antibodies. and protein shock results.- These p otective antibodies react violently ns in'the firstinjetted protein, Radiological research has shown that protein shock does,not occur t the individual has been irradiated : before the first injection; in other words, irradiation inhibits immunological responses, - 0 or * r, *. -46- 3 rA 13* .0, BY .SWALLOWING BY BREATHING or Twointo ways the of body getting radioactive material JJ Peotection against breathing ,dust ,--; Washradioactive up after material.handling SONE SAFETY. HINTS Fig. :3 material.Don't eat around radioactive Eat in the lunchroom. e- . , Theimmunization inhibition isof a.immunological good technique4to response use can in betransplanting of medical benefitorgans oror tissue. it can be-a medical hazard. For , example, the life of a 4.. Such = ingpatient bone needingmarrow takennew blood- from anotherforming person.tiss4,may be saved by first irradiating the patient end then inject-- The foreign bone marrow. will not be rejected bedause of the effects of the-prior r adiatiori. sr However,left without the absence adequate0 of defenseimmunological against response even ordinary has its AlSeaSe,-and disadvantages the too. patient may even dig frOM an infec- g For example, the body is tion like the common cold. OTHER'RADIATION DAMAGE OtherThere isdeleterious ,evidence, effects from work include on experimental cancer, cataracts, animals, and that improper'cell radiation produces differentiation abnormally during rapid the aging. first ij a few weeks of pregnancy (resulting in malformation of the embryo's organs and tissues). 'MEASUREMENT OF RADIATION DAMAGE The Roentgen The roentgen is defined as(the an exposuremilliroentgen or dose is of1 /1,000 X-rays roentgen). which will form nit1.6 ofx measurement for external radiation exposure is the roentgen( ). It.is.a unit of exposure to radiation but not I012 ,on pairs when absorbed in'one gram of.air absorbed by the body due to radiation. -48- Nohowever, human could this survive is-not 1-,:000 the sane roentgens as 1,000roentgens of delivered to total body radiation delivered in a short time. only a small portion of the body; a,pdr-, Biological, exposureson might timewell,survive are all importantthis. factors. In terms of harmful effects, body area, intensity of radiation, and. . Because of individual differences, the t, term that is usually used medically is the so-called lethal kill all of a certain fraction of a popu dose. Thedelivered lationlethal exposed doseto the (LD) fortotal is a thespecifiedbody amount in 24 time ofhours rddiation or less, required to The LD/50 for "penetrating external radiati n is which means that at this intensity and time duration, about 500 roent ns Athalf 200 of tothe 250 people roentgens exposed of wouldtotal eventuallybody radiation die. delivered In 24 hoursor I les4L-Some people would die expoSure,right away; would others result would in survive,persons suffering nausea, From 100 to 200 roentgeni of total body fatigue, vomiting, and'general sickneSs; but radiation for the sam there J.1 would not be any deaths. At about 50 roentgen'sslight temporary-b1ood of total body changes (whichtheir-bOdies,would.correct in time).. radiation, for the same time exposure, - .1- Atpersonsical i5 roentgenseffects. exposed ofwould total have body radiation; for this same short time, there mould be no noticeable med- withinThe term, a specified medium lethal time, doseinstead (MD) of is the sometimes LD/50 expression. used for the'dose which kills 50%;of the N` individual actual applications, the biologic effectiveness of any. radiation depends upon several factOrs;, . T Possi- blematerial factors temperature, would include: etc. type and degree of biologic damage, absorbed lose rate, material pH Theitem rem (roentgen equivalent man) is a unit of radiation dosage which .is the biological equivalent 5b the rad; in other words, it takes the RBE'into account. Dose in ,rem = Dose in rad x RE The rem i$ defined,by the relation:, nuclearBecause theradiation, tgrl.k_RET42P1 it is aunit of biologic o of biologic damagethatgresults.fromabsorptionValues on the next page VTesents of sow. 6. of the associated biological effect's of radiation pROTECTIONAGAINST RADIATION-HAZARDS see Fig. .4 Thebe dosekept tos6 anylow individualthat genetie'damage must be cannot kept below Occur. certain levels.., Thg,d61 to the generalpopulationThere are ccrtain:eritical'organs must that Must be taken .tions requireinto thenzirocessconsideration of in figuring the cell division, especially those of maximum .permissible level (MPL) , the skin-gut wall,. the blood-formingfor individOals. 4 1 Cells whose fUnc- * tissue,pH,refers and to ttte the gonads,relative are acidity most sensitiveor, alkallnity of 4 radiation and are called critical organs. -,a materia Organs such '4 Fig. - Table ti SUMMARY OF EFFECTS LIKELY TO RESULT FROM' HOLE BODY' EXPOSURE TO RADIATION . THE BIOLOGICAL 1EFFECTp OF RADIATION . 0-25 Rem 50 Rein 0 100 Rem 200 Rem _ f 400 Rem . 601) Rem- . No detectable, Slight tran- Nausea and Naus 0. aaa ,. Nausea and Nausea and layedProbablyclinical effects. noeffects. de-0 otherchanges.sient clin- blood No possibleingfatigue above vomit-with 125 r. 24vont'lowiAg hours latentfol- a wi-: "n 1 to 2 hours vomitingafter a,in latent 1 - $boxt-letenttovomiting-in 2 hours.-- 1 ableically,detect- effects.- Marked changes lood condi-1 oneperiod week. of Epil-about periodone week. cf-about Be- perioding-initial 'follow- ' possible,Delayed effects but i delayedtion with recov= appeEation, lossegen- of ,--. . eoilation,ginning of Diarrhoea,nausea. 'individualimprobable'. very ious effecthe average expeciancy.-ingery. of life Shorten- hand otherASereil-Weaknesssymptoms, sore throat such sore loss,eral of ac6ompanidt,by weaknessappe-.tite, and gen- - ofvomiti.g,throatinflammation mouth towardand A _ . andinProbably diarrhoea.a2,tO,6 s deathweeks 11 of-mouththroatinljainmationfever.. inandSeitere the°;----' (4g4LIUM-ion-piiFever.;week.end of-first rapid, t _ fractiindivi n 'ofuals the gYmptomsthird week. such asdeath the as second early?-: , . - Recoveryexposed. likely diarrhoea,1as pallor, weekeventual with 'deat '' . ' ' catedunless by compA-poor 7:7" TTebleeds,,and rapid , 'of probablyall exposed is-' . . . previouS . emaciation'in 4 th-er-frurth individuals. . t rieimposedhealth, 1super- or infec- t week.deathsabo in 2 to Some ,, .- , i -ficinS. , 6 weeks. Even-- . probablytuall,y death 50% ofto, ,____ ,, . - . .. ____------the-exPizTs-da /. individuals. . . as the thyroid, which may.be greatly damaged by ,a concentrated internal dose, or the eye, Which is sensitiveIn practice, to radiatIon and usually espon it is oonsideration of the dose to by the formation of cataracts, are.also criticalonle,ox organs. more of these critical, organs that sets the , permissible limits of dosage far the rest of the,body. ti tr Theofkradioactive simplest general radiation approach below to theassuring level radioactivethat is known radiation to Ardduce protection a detectable is to set . , t "effect on the body; i.e., the,maximum level keep(2) the keeping level_below the radioactive25 reins. source at a safe distance, and (3) shielding the radioactive source This can be done by (1) reducing the quantity of 'a.radioactive .= material,'. 4 from 4 otherwise exposed persons. INVESTIGATION NO. 1 a PurAoses: (1) to show some effects of radiation on a population lof, yeast EFFECT OF RADIATION. ON MICROORGANISMS 44 cells.. Materials Needed: (2) to determine the LD/50 for a pogulation of yeast cells. germicidal ultrayiolet lamp dry yeast .;) potato-dextrosesterile petri dishesor grape juice agar withErlenmeyerstop cotton watch flask plugor clock (1 liter-capacity) with second hand -53-, r 6 Materials Needed (cont.) graduatedsterile(1 liter distilleddYlinaer capacity) or water Ntolumetric flask metricsterile rule pipettes, Expasureintroduction: to radidtion can be fatal to an organism. , 0 \ The individual organisms in a snOf course,cies vary t';e considerably more radiation" to cerlich an organist 'is exposed,in the more, likely it is.the to amountbecilled. of radiation. they arp able to . Some i:idivi ch ala may be killed by very little * radiation,,tion. on a particular'species is to speak of someaverage fatal dose. , . Ethers may withstand- much more. One convenient way to -desc Such a dese-has been defined is e the effect of radia- otherAgetheLamountof.radiation fatal50 percent dose (the ofthe term,L10/50, population that:will meaning willkill bejust "let -ilied 50al percent doseonly for 1f-the of 5070 the radiation:doSeof individualiin the, popUlation"). isa speciesgreater (ID/50).than the aver- *The. ifProcedure: the petri dishes'Of agar have not already been, prepared for you, melt the agar. and pour it into . "Weigh sterileout 0.75 petrig of drydishes, *yeast using an careful aseptic techniques. susp nd it in one liter of sterile distilled water. fi Plug-the liter' flask with cotton and swirl it tp mi4 the contents thoroughly. -54- `Using a pipette, otransfer 5 ml of the yeastturn suspensionthe lamp on. into a sterile petri dish. CAUTION: J DO NOT LOOK DIRECTLY-INTO THE Place the':- ltraviolet lamp, 10 cm above'the table top and LOT. TT IS HARMFUL TO TEE EYES. Place Removethe petri the dishyeast containing suspension the from under the lamp. ml of yeast _suspensions under :he lamp for exactly 5 seconds., Using anothe- sterile _pipette, transfer-O.1 mi .;,f overthe theirradiated surface yeastof the suspension agar by rotatingto the agar the in dish oneV withof the a gentlepetri al,silits.circular motion. Spread the suspension t7trily Mark the cover c -f theIn petri:the same dish manner to indicate irradiate .the other length samples, of exposire chi:; at(5 aseconds). tire, ,76r poTiods; of 15, 3-, and 60 ,w,cc,ndo C.T1 offor agar. 2, 5, 10: and 20' minutes. Mark each -with its respective length of exposure to the ultraviolet irradiation. Place 0.1 nil.of,each of the irradiated samples in a seprnie petri disk. - Inoculate each of two agar plates-with 0.1 ml of yeast suspension which hes not been eziTo ed to ui:ra- .violetDuring radiation.daughter this cells incubation will form period,'any visible yeastcells colonies.that survived the radiation exposure will multiply and their Then incubate the inoculated agar plates in the dark-at about 25° C. for 48"hours. . number9ountof colonies:in theof coloniesnumber eackirradiatedof present colonies in formedthese culture controlin each (experimental culturesof the non-irradiated represent culture) 100%to culturesthe survival. average of cells. number of colonies in Then cOmparb the number Let time average - tJ twothe untreated percent ofcultures;'from survivors this comparison, find the percent of survivors. is the percent of cells killed by the radiarion,tic4tment.) (One hundred perient minus , - centPrepare-a of the graph, original with population the length killed of. time on-the'vertical-axis. of exposure to irradiation on-the horizontal:axis-and the per- Be especially careful id plotting the ,,. willcertaintime be on much -theLhorizontal number farther of secondsapart axis. than or minutes.the points representing 15 seconds and 30 seconds. Remember that each square on the The points representing 10 minutes and 20 minutes,therefore, -- aph paper is supposed to represent a Draw a 4mooth curve through the points. A 'QUESTIONS toat 7 1. ApproxiffiatayActsline-from the curve,the what point lengthdrop on aofthe vertical exposure vertical linekills axis tothe onerepresenting halftime the scale cells 50% and fatalitie'.?' readt ,, t (Draw a straight horizontal approximate time exposure.)Where this line inter- 3.2. presentbutIfCan youayou different experimentwere explain planning speciesthe to shapepredicta similarof ofmicroorganisms, thethe experiment,using LD/50curve? for thewould new theyou species? samebe able techniques to use informatioftand lengths offrom'the Explain: exposure 4. Explain.Wpuld you expect the shape of the curve obtained for this,new species to be about the same? / SELF-TEST ON DANGERS OF RADIOACTIVE RESOURCE PACRAGE.2 -2 1. What is meant by direct action in radiation damage to the human RADIATION TO THE HUNAN BODY body? q.2. What is meant by j.ndirectTarget Theory? action in radiation damage to the human body? 4.5. WhatExplain is the the difference meaning of be'tween action somaticat a distance. damage and genetic damage? 6. Define(c)(b)(a) theradiationradiati6nradiationpoighning following: injurysickness 8.7. Define'theWhat are two following: general ways your body can be exposed to radiation? °(b) Rad (a)(c) Roentgen KBE (g)(f)(e) 111,DLDLD/50 9. Radioactive.(2)(d) Rem radiation protection can be assured by:, (1) (h) MPL and -57- ANSWERS TO SELF -TEST ON DANGERS-OF RADIATION TO THE HUMAN BODYRESOURCE PACKAGE 2 -3 RADIOACTIVE . Directbarding action Orticles is the from radioactive materials,. disruption of some part, of the structure of a cell-by . the action_of bom- 2. Thestructure) theory that is calledtreats'radiation the Target Theory. damage as being caur,..-.: by hitting a directly, but.extramely relevant target (specific 3. intoactiveIndirect combination groups action of iswithatoms,called whereno cell,molecules, part free of the radicals are7formed.the.cells of the body'areresulting interdependent in disruptioncell "structureof cell functions. is damaged These very active free radicals enter and the prin- 4. cipalActionpartactiodsecretions connecting whichat.a at adistanceinitially poureddistance link into occurs isproduced(since thethe because bloodblood.the parts stream affected can can the slight variation of.secretion).- *e effect on the body of a slight variation of some be very large, and these effects are be a distance away from the irradiated known as 5. , Somaticof dhe damagecell to is reproduce); any damage genetic which affeas.thacell functions (but not damage includes damage to the genes, includingwhich the ability.causes impair- went in the ability to reproduce offspring. having the characteristics ; _ ' of the parent. . 6. (a) Sickness produced by a massive overdose of penetrating external radiation.. - , (c)=(h).Localized Illness resulting injurious when effects. radioactive materials enter the body and cause such . diseases as 7. xposure-..(ingestion)Two general *ys the of body radioaCtive can'be materialanemia by mouth- and cancer. or_nose. exposed to radiation are (a) external exposure and (b) d inte&al (a) The roen pairs w en is the absorbedquantity inof onegamma gram of air. l`- iadiaAion or X -rays which will form 1.6 x f , 101 , , . CO (b) The rad i qual to the energy absorption of -59- 100 ergs per gram of irradiated material. -.. (c) The ME o (of specified energy) to theabsorbed dose of thegiven radiat' a given radiation is the ratio of the absorbed dose (r.. . c r required to prodpce of gamma radiation (d) The relli'iSa unit of dose biologicallyaccount.the equivalent samebiologic effect,, , . . to e-rad, when the RBE is taken into (e) MW is the dose which kills 50% of the , expo a individuals within a specified time. (g) LD /50 is the dose of radi specified-time.time.LD is the amount of radiation requir on which would kill half of the *;posed individuals 'within a to ki.31 Ali exposed individuals within a specified 9. Radioactilre(h) NPL is the maxi n. m permissible level of radiation which .. assures ..no harmful effects.' - ' . d'active =(2) ance, r rucing and (4) the shielding qu4tity Ofthe radioactive source and/or material die involved, (3) ation below the level that.A Is knowndiation to produce a detectable effect proteddOn Gan be assured by: (1) setting the maxitum level of radio- putting the source at a Safe on the body, O persons exposed.

4, -60- SOURCE:PACKAGE 3-1 There are many benetitial applications of radioactivity. SOME BENEFITS OF.RADIOACTIVITY This min course discusses only a few. RADIOACTIVE TRACERF biological processes in man, ani- Radioactive isotopes are widely used as tracers to trace or to monitor .ef , signaldilhich can be detected by electrical t' coals,organs,or-chemical and tissues, plants means, (seeetc. and Fig. this 1/below): makes it Suchpossible tracers to mapsend their out paths thrcluth an organism or its component

Aids in Diagnosis RADIOACTIVE.-.,...:21-reatment TRACERS of Diseabe Fig. 1' Radiation Therapy -61- Tracers Used in Diagnosis id the body. Medical research has shown that the thy- The'thyroidroidisotope gland ofgland is,/one of the important glands will absorb_practicallyiodine is introduced all intoof thethe elementbody (the iodine isotope whiph behaves enters chemically the exactly. like' ordinary If a radioactive howmine iodine),well the the extent thyroid and is the functioning. time involved in iodine absorption by ve thyroid; these measures arei will be absorbed by the thyroid gland. By the. use of a Geiger counter, a surgeon can deter- 'keys to TheSome application Other Tracer of Applicationsradioactive elements as tracers is based on the Evict that with a the help of the Geiger counter, exceedingly small quantities of an isotope can be traced. For eXample, bismuth is a fstable element.Ays. of considerable medical interest. 'One isotope of bismuth, calledStable RaE, bismuth has a is prepared with a small addition of RaE (which has 1 exacta the same chemical half life of 5 theproperties); body for radioactivity.then the path of the bisMuth in an animal or human is Since cancerous tissue retains'larger amdunts of bip traced by testing various, parts of th than healthy tis- /Radio ctisue, e sodiumthe location is also of used cancers in medicine. can be pinpointed: It i sodium-24, an isotope of / sodium. -62- let + n 7.11 if ,,---,, / Sodiufa Radiosodium 13'11°. 1. emittingRadiosodium a beta has particle,a nucleus andof 13the neutrons. transmuted element becomes magnesium. This nucleusis unstable. Radiosodium acquires stability by 12 15+ Radiosodiva .1 Magnesium 12.'n° _,- + Beta particle - One of the uses of radiosodium is to investigate poor circulation of \z*) the blood due to a circulatory forearm.obstructi9n. At the same time a Geiger counter, A small quantity of a so]utio is placedof near radiosodium one foot. chloride is injected into a vein in the the Geiger counter in a few seconds. If-cirtulation is normal, the theButradiosodium Geigerif circulation counteris carried can'beis poor,in themoved there blood from is stream, placea delay to inplace the unpilVime thethe region 1 and isdetecte b blood reaches of obstruction of normal blood he foot. During the delay, circul'ation.is found. Oes -63- *ta 41- Cattle-Feeding Tracing Fertilizer Action 1 TRACERS IN AGRICULTURE, Plant Growth Studies Fig. 2 . Experiments In agriculture, radioactive isotopes are helping biologists solve some of the mysteries That' are'using raaioactive carbon and hydrogen ' o. trace the intricate of how plants processduplicatelive and called grow this photosynthesis,(see process Fig. and2).. thus the produce process Lero by which plant tissues are artificially (see Fig. 3 on next page). formed. Some-scientists hope to ple,Radioactivity such use hascan producedalso be useda new to kind change of oatthe resistantinherited tocharacteristics blight. of plants and animals. . For exam- wears,checkThere radioactiveengineare many wear other ironin testuses is detectedengines.for in the lubricating oil system. radioactiveYtracer elements. The engines' pistons are made of radioactive iron. For example, radioactive iron is used to As a piston -64- In greenhouse laboratories, agricultural research workers often AGRICULTURAL TRACERS Fig. 3. trienttogrownelements"tag" photographic inoror such theselabelmineral as greenhousescertain film,phosphorus has beenthe fertilizers research distributedor-under iodine. research workeror mineralsthroughout canconditions till with the how radigadfleareplant. the exposed nu- When leaves of plants Thisfield. often allows for better use of fertilizer methods in the . Radioactivity may be used to determine the thickness of sheets of metal, to trace leakage in pipes, to find flawi-in pipes, etc. ' These uses represent only a 'Small portion of themany -- technical uses of radioisotopes (see Fig. 4 below). r - J Gaging Sheet Thickness SOME. TECHNICAL USES OF' RADIOACTIVE TRACERS Tracing Leaks in Pipes Fig. 4 3 2hnding Flaws-in Metal Parts + 4-7424.- An important use of radioactive materials is based MEDICINE AND DESTRUCTION OF LIVINGliADIOACTIVF/ISOTOPES CELLS IN THERAPE upon the fact that they emit energy'which can bring 1 about the destructionlof living cells; for example, in,ihe treatMent of cancer. 4 -. A cancer is a group. - grOwing of cells growindmuch too rapidly. tissues and thereby to brit RadioaCtiveabout radiation an arrest is usedof the-cancerous to kill the cellscondition. of,these (see Fig. . , 5 on next rapidly page). illustrated by the use of certain radium preparation's. Ra- Thedium therapeutic preparations effect have of a radioactivityslow, destructivi.effect is on the skin,. producing sores similar to , burs.';' This . effect proves beneficial in the treatment of skin:tumors, for tumors are more susdeptibteto.radiation destructionalpha rays, than since healthy-tissue.. alphas have little In treating tissue penetratingSkin tumors, beta ability. ---_, and gamma rays are moreTherefore, effective radium than- proper (being an - , whichalpha after-short emitter) is half not lives,used. emit two beta particles and gamma rays. Radon (although itself an,alpha emitter), . Thushow-ever,-ha-s-daughter radon is very-useful-for elements . . 13., Iiiradiotherapy. hospitals, ra (the costly parent substance), in the *form of a chloride, is kept in a c ose 'd glass" COntailieefromwhiChCollected intinY, radon;needle"-(glass the radioactive tubes as by-Product,-is thin as taken at regular needles) " about kinch long. intervals. ilethe needles are The radan_is 9P used on the patient, they lose their activity,yith a life of a , P after one orf two weeks, since most of the da;)S. These needles are.o&no_further,thedical value iadOn has diginte-- . ;1"ii til tr.tio; .(these old-radonneellesgrated into Rap, could which, be in.valuable turn, hasfor aa halfphysics life lab- of 22 years r , .oratdty,rays,. where -can. polor.-..am, be separated which out).- is a good source of pure alpha : 4, 9 Anotherliving usetissue fbr is.the inproperty the sterilization of radioactive of foods material and drugs.to destroy The foods or drugs are sealed in moisture-proof. wrappers to pre- S f" vent contact with outsidelair. Then they are exposed to massive- I - - .1. doses of radiation, so that all living organisms in,the package , lized.are killed. Further, if a lesser dose of radiation is used, theIf the organ" ms-are killed, 'the food is steri- -. 4 41. II 10. 1 food can be pasteurized (that ii, not all of the organisms food can be stored KILLING CANCEROUS CELLS Fig. 5 forare akilled, reasonable but enoughtime without are killed being that destroyed the by bacteria). receivearoundcobaltRadioactive onto thein overdosepatientcanceroug"lamps" soofdirect tissue. thatradioactivity. healihy,,,tissu.illrays fro not The radioactivez. p" revolves .768- Whereby the radiation use of heat,would sterItization-is used in the manufacture of drugs,, it is often because sterilization damage the drug s. Radiation can kill bacteria without raising the temperature of the drugs. :RADIOACTIVE ISOTOPES TO MAKE AIR coNpudTivF The accumulatio of static electricity is a serious hazard 6 in industrial areas where explosive vapor D -air :static accumulationsconcentrations exist, of electric al charge because the rays from the radioactive Radioactive isotopegs(radioactive static , . eliminators) -can be used to eliminate material ionize the air and form a conducting path along whieh,electric chargd can-flow to'the ground. ,, This-process is identical : to that of a lightning disCharge, only not aserectrical violent and contact without,.IL with.the material itself. the nsparking" (bolt). Obviously; it . C 1 is not necessary that there be any RADIATION USED TO =LEE THE ATOMS . - , 9 ir OF, PERTAIN MATERIALS It is generally ,:. believsditc tit is radium pfi a,watch or clack dial 'which c glows in the dark. This.is not so, but the radioactivd, radium does emit energetic particles Which cause a chemical phosphor, such . page):as zinc sulfide, to glow%in the dark when bombarded (excited) by these emissions (dee Fig. 6 on next .

P. i s..., -. Andtherchangesfield important of can chemical be usebrought'abouc processingof trims-phenomenon which can of change radioactive the properties excitation of isa troduct.in the .'s By the use of radiation energy, certain chemical For to,theexample, temperature when polyethylene of boiling was water. first developed, it could not be subjected '7 Now, at a certain point in-the product 6 activetion process,materials. pol7ethyleno is subjected to _the emissiOns Item_eezcain This radiation frees a couple of hydrogen atoms (Ialich, r released as hydiogen gas) and thus changes the tanner in which the atoms of i , . polyethylene are linked together, producing so called cross-linked polyethylene. can,Such,a therefore, polyethylene betuSed-in. can basafely many applicationssubjected to as boiling a substitute water temperaturesfor and 4 glassware, (even when the container must be sterilized, such as baby bottle, etc. VOLTAGE PRODUCTION. RADIUM WATCH DIAL Fig. 6 p TheThisand quantity isused the wherever directof energy productiona dependable per emission of sourceelectrical is relativelyof Ihng-time potential minute, electricalenergy from but the a energyso called inreleased small "atomic quantitiesfrom is requited. battery" can be maderadioactive atoms. -70- ;RADIOACTIVITY AS A MEANS y OF WINO ARTIFACTS animals, and organic artifacts is carbon-14 (14C). -'0ne common radioactiveelementicallyCarbon indioxide the used plant's (CO2) for isdatingmanufacturing constantly plants, beingprocess. removed A result of this photosynthesis fromis the the air by plants. It is then used photosynthet- storage of carbon-14 6 cosmic(originally rays which in the interact atmospheric with stableCO2) in the nitrogen ( plant's tissues., Also, carbon-14 is produced 1./p nature 1 74 N) in the atmaPhere to produce radioactive 14 6 C. by Assume that the percentage of 14 6 CO2 in the air has been approximately have a:COnStant concentration of the same for millions, 14of years, C in their tissue composition, - LNO, becauseRemember1 they that use all this plants fixed0 ought-then percentage to of radioactive 14C in photdsynthesis. 6 When the plarlt4s alive, photosynthesis proc- a ess. 6 C is continually disintegrating;Therefore, the but amount itis of C-14 in living.plants is the same as the amount of C-14 in the also continually being replaced by the t . atmosphere, Whblr..,!-heand the plant dies, no more 14 6 C concentration in the plant must begin to 14 6 CO2 is replaced by photosynthesis; now been dead: decrease. If an archeologist unearths By measuring Milky disintegration can take place 14C 6 C level in a plant, logs in the exca- werevationit iscut ofpossible down. an ancient to tell city,'tadioactive how long the plant dating has of the,timber will indicate approximately when the trees 771- RESOURCE PACKAGE 3-2 HOWHADIOAGTIVITY BENEFITS MAN v t% 1. Howand do plants? radioactive materials make it SELF TEST QUESTWNS ON possible to trade biological pr9cesses in man, animals, 3.2 . GiveNamP two uies.for radioactive a medical- clinical use:lor-rhdioactive sodium. materials in medicine. 5.4. HowGiveing doesthe living usecells. of certain radioactive at least tonimportant uses for radioactive materials reduce accumulation of static isotopes; hased,;On'their property of'destroy-. electricity? J° 6. this.In the case of a radium dial watch, is it thre radium that glows in.the dark? Brialy,discuss 7. WhatsomewhatGive an examplethe chemical of how and radiation physical energy nature can of bethe used irradiated to ome of the ways radioisotopes are used in agricuitiil technology? excite atoms and to thereby change slibstance. 10. 9. ExplainartifactsGive a howfew fannd-dfoundradioaindustrial tive usescarbon ancient of radioactive cties after materials. excavation 14C is used to date 14s, bones, timber, and other organic by archeolOgists. 9, ti -737 RESOURCE PACKAGE 3-3 1. By sending out signals that can be detected by electrical and ANSWERS VO SELF-TEST QUESTIONS ON HOW,RADIOACTIVITYBENEFITS'MAN chemical means. 3.2. materialsAsRadioactive,sodium radioactive in the tracers treatment is inused diagnosts of to certain invesOlgate.poor and diseases treatment is circulation ofoften certain called ofdiseases. radiationblood in man. The use of'radioactivether4y. 4. TheIn raysthe treatmentfrom the radioactiveof cancer and material in the ionize steriliiation thelair andof food,form and an o drugs invisibile conducting path of ,5. 6. No.fide)ionized to air glow. molecules, along which electric charge'The -can radioactive flow.to the radium emits particles which cause a phosphor material groundt---.° (such as zinc sul- 7. - linked polyethylene,'for glasscouplePolyethylene in ofmaking hydrogen cannot such atoms thingsbe subjected areas babyremoved tobottles, boilingand escape etc. water; (as buta gas). if treated with which can be put in boiling water and which can be used as a subs.titute . The resultant product is cross- radiation energy, a 9-.-----In-industry, radioactivity8. is used to determine the thickness ofliveIn sheets agriculture, and ofgrow. radioactive isotopes are helping,biologists solve the mysteries of how plants 9 metal,-tO trace g 10. Whileactivel.ybutleakages whenorganisms the inwhIle'no organism. pipes,(plants lifeto dies,or find animals)processes theflaws amount arein are pipes, aliye,of occurringwhich .i-7C etc.the beginwto decreasewould =many 116t- Nir in them is maintainedLit a constant, level; beCause it is decaying c additional . 14 4C,fromradio- tellthe environment. how long the organism has been dead. By measuring the level of : Thls is called14C left carbon in6 thedating. deirased organismt,,it,is illos§ible to absorb, ''' Ai 6 -75- SUGGESTED OUTSIDE READINGS RESOURCE PACKAGE 4-1 II you look through,current newspapers, scientific magazines, and other such sources, you will find how manymany artles on.radioactillitythe, Atomic Energy Commission-(yoursuch. articles you teacher can find should in a havereasonable theselmblications);AEC time period. and its many applicatibns to Science, technology, and industry.. See addition, use thp materials published publications are authoritativeings from a fewreviews of the of booklets.publishedthe current state ofby nuclearthe Atomic science. Energy Commission; The following are some Suggested read- these may be used as a starting point for your outside readings:--- I 4U.of"Radioisotopes S. Technical Atomic.. Energy in,,Medicine"'- Commission/Division By E.W...Phelan formation HistoryIntroduction What is Radioactivity?Radiation? PagePage:5 15 a Diagno,sis WhatBOWWhat.Pinpointing are Doare YouRadioisotoressUsed? Radioisotopes? Mean Disease by tracer Atoms? PagesPagePage.6 7119 11-29 tummaryTherapy Aeiivation AnalysiS - or- -Pagepage. 30 30 ASuccessfut'CaseGeneral Principles' Page 31Pages 32 - = Jeletherapy . -77- Page -42 L "Whole Body Counters" II . T e Sensitive Detectors Geneva Counter By Frederick W. Lengemann,andi-John H. Woodburn PagePages 2-7,8-9 1 -.The Radium. StoryCryStal-COunters.ATle PotassiumNeW Body Contaminant40 in Human Bodies Liquid Scintillation Counter Pages 15-1613-1417-2010-12 U."Food S. AtomicPreservation Energy byCommission/Division Irradiation" By Grace IL Urrows III t Preservation of Man's.POd of Technical Information OP Pages 4-7. ft 4 TestingRadiationHow Food Program Spoilsa New andTechnique Devices ' PagesPages 10-18 8-936-3819-35 'Economics FruitofTotal Food Stand'Econo Impact Presresh Fish Every Dayserving .t Tasteof the Orchard s of.the'Future ation PagesPage 52-5448-5139-42 47 -78- . IV ., "Radioisotopes in,Industry"By Philip Baker, et al Detectable Morsels ofU. Technical S. Atomic Info Ener nation Commission/Division Page 1 . Explaining RadioisotopesGauging , " Pages 2-910-18 RadiationTracerRadiography Uses Processing ";- PagesPages 35-3619-23 23-34 RadioisotopesWhatPrincipal the' Future Industrial Application Holds in Industry Products and Activities V PagePagesPages 4642-45 39-41 TechnicalU.By S. Walter Atomic Information E. Energy Kisieleski"and Commission/Division Renato Basserga of"Radioisotopes and Life Processes" Cell Theory DNA is t e Secret of .Life * Pages. 2-9 Radio* esis:o e he BiologicalTheAutobiography Detectives of Cells -/ Pages 1015-24 -14 Protein Synthesis: Synthesig: Language Into Another How to Translate One The Molecules that Make ,t Pages 35-3625-34 CellConcluaionIsotopes Cycle inand Research: Gene Action. Secrefthe Difference DNA Probing the Cancer Problem Life is thie PagesPage6 45-43737-4 . "Application of Nuclear Science VI Agrigulture. Atoms' in Agriculture" U. S. Atomic Energy Commission/Division Howof TechnicalAre Isotopes Information Used in Research By Thomas S.-15sborne to _Pages 2-1- . Pages 4-5 RadioisotopesPlant DiseasesNutrition as and Radiationand Weeds Metabolism Sources I - Q -PagesPages 8-9 17-22

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