A New Program To Teach Nuclear and Radiochemistry to Undergraduates Gary L. Calchen Department of Nuclear Engineering, Pennsylvania State University, University Park, PA 16802 James Canelos College of Engineering, Pennsylvania State University, University Park. PA 16602 Although courses in the subject of nuclear and radiochemistry have been a fundamental part of chemistry curricula for the last several decades, there is a great deal of variation in (1) where this subject is taught, (2) what topics are covered, and (3) who the audience is. Courses in this subject are offered by less than half of the major chemistry departments in the country, and the courses are sometimes taught in other-than-chemistry curricula such as nuclear engineering or healthphysics.~imilarlycourses may f'orusonel~mentsry aspects of the subject, or they may focus on topics at the forefront of research. In what follows, we describe a program developed to increase comprehension in a specific course on nuclear and radiochemistry. The course, which is offered annually by the Department of Nuclear Engineering at The Pennsylvania State University, is listed in the nuclear engineering curriculum and is co-listed as an advanced undergraduate course in the chemistry curriculum. Currently, the course is required for nuclear engineering majors who comprise the major portion of the enrollment, which generally ranges from 45 to 60 students per offering. Hefore we present the details of the program, we mention some background information that m i y provide a perspective on the teaching of the subject. In recent years, radiochemistry has ceased to be a field of active research, and the utility of radiochemistry as a tool for studying nuclear reactions also has ereatlv diminished. But. radiochemistrv is used in many gelds of research such a s biology, medicine, and eeochemistrv. The conseauences are twofold. Firstlv, .. a t the present time very few graduate students in nuclear chemistry learn the art of radiochemistry. Generally, chemistry departments have either few or no nuclear chemists, and in departments that do have nuclear chemistry programs the junior members are generally not practitioners of radiochemistry. Primarily radiochemists are found in other departments and at national laboratories. Secondly, since radiochemistry is important in many fields of applied research, availability of instruction becomes a problem, and the problem arises because very few chemistry faculty members still do research in radiochemistrv. Hence. the svnerev between research in a field and the associated teaching of ti;k subject is lost. Although a very active discipline, nuclear chemistry has remained a relatively small field. Therefore, much of the research a t the forefront of nuclear science is not clearly distinguishable as being either "nuclear chemistry" or "uuclear phvsics". The maior identifying label arises from thedepartmeit to which the investigator belongs. As aresult of the interdisciplinary nature of the subject of nuclear chemistry, we decided to find out more about what others teach under the rubric of "nuclear and radiochemistry". Durine sorinr semester 1985. we conducted a survev to appraise-bekerihe current s t a t k of the teaching of nuciear and radiochemistry a t a national level. We sent a one-page questionnaire to the chairmen of 67 chemistry departments in the United States that we selected on the basis of either size or reputation from the ACS Directory of Graduate Research ( I ) . The questionnaire included queries about course credits, course type, and specifics such as either lecture or laboratory, frequency of offering, enrollment, text, prerequi-
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sites, and i t requested a brief course description. Although we surveyed primarily departments that have graduate programs, we believe the information obtained on undergraduate courses is also representative of courses taught a t undergraduate colleges. We received 48 responses from the original 67 schools surveyed, and the responses from 22 depar;ments indicated that they have offered at least one course. Interestinrly, we receivedcourse descriptions that varied significantlfa&oss the entire spectrum from elementary courses in radiocbemical applications for students in non-nuclear-chemistry fields (which may include laboratories) to rigorous theory-based courses intended for eraduate students doine thesis research in nuclear chemistry. The courses often reflected the research interests of the instructor. Although these results are not surprising, they are worth mentioning. These results suggest that each nuclear and radiochemistry course evolves according to the interests of the individual instructor and to the needs of the respective department and students. Despite the variation in course content, most of the departments (16) specified Nuclear and Radiochemistry (2)as the text for a t least one course. No other text appears to be nearly as widely used. This final observation is important because one of the major reasons for developing the materials described below was that this particular text was inadequate for our audience.
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Speclfic Details of the Course Problem Three years ago in the College of Engineering at Penn State. we started to develoo a course in nuclear and radiochemistry for nuclear enginkering juniors. This course would provide the nuclear science backaround that the students would need for later courses in 1;-actor design, radioactive waste control, and radiation protection (health physics). The courie would he three credits of lecture, and no lahoratory would be offered because the department offers a laboratory course in radiation detection and measurement. Similarly, no material would be presented on radiation detection and measurement. Additionallv. the course would prepare a few undergraduate seniors ( j j f o r graduate work and some eraduate students for research in nuclear science. Given these considerations, we prepared materials on the followine woics: (11ohenomenolom of radioactivitv, (2) nuclear pripekies i'n&ding angula&omentum, electric and magnetic moments, parity and statistics, (3) introductory topics in quantum mechanics, (4) nuclear structure and the shell model, (5) theories of alpha and beta decay and gamma-decay selection rules, (6) kinetics of radioactive decay, (7) interactions of radiation with matter, (8) scattering kinematics. and (91 . . nuclear reactions. We offered the course twice covering these topics, and we used the aforementioned textbook and handwritten course notes. After each offering, we ran course evaluation surveys. (See, for example, Cauelos, Villano, and Rosenstock (4).) The surveys and our ohservations indicated that the textbook was poor, the lecture material was abstract, the homework was difficult, and primarily only the better students were comprehending and benefiting from the course content. Although part of the problem was
Figure 1. a. An iilusnatlan of medeuteron bound by the nuclear force. Here, the two spheres are shown to spin in the same sense illustrating the coupling of the spin-one stable state. b. An illustration of the dissociation of the deuteron by a photon having energy In excess of the deuteron binding energy.
Figure 2. a. An illustration of the spin and the orbital angular momentum vectors in which they couple independently to an external field. b. Here, the Spin and wbital angular momentum are shown to interact strongly with each other. The resunant Jprecesses about the direction of the external field.
that most of the students tookarequired sophomore modern physics course concurrently, the primary problem was the abstract and difficult nature of the subject matter. Before the third offering, we had to choose between either reducing the intellectual level of the subject matter presented or increasing the level of comprehension without significantly reducing the intellectual level. We chose the latter.
However, these ideas are far from a ~ o a r e nto t the students. who, to heginning this course,have taken only three physics courses. Figures l a and l b are typical illustrations that we developed, in this case to illustrate the nuclear force and the binding energy of the deuteron. Early in the course, we introduce the quaiitative (quantum merhinicalj rules for adding angular momentum vectors, these rules are necessary lor the students to understand the sinele-narticle shell modbeta and gamma el and the effects of angular moment& decay. Figure 2 shows two illustrations developed for this purpose. In addition to illustrations developed directly, we have selected fieures from a varietv of textbooks (8). . . and in many cases we have added color cuingvia a computer-generated graphics system. The effects of color cue schemes on improving student retention has been documented. For example, earlier research on this characteristic was known as cue saliency research, indicating that the in-color item is easier to recall as time passes (91. We have developed the 14 videotaped tutorials specifically not to take the place of the rlassrn~minstructor. Instead, the tutorials serve as an out-of-class medium for learnine problem-solving methods. On campus, there are several learnine centers that ~ r o v i d ethe facilities for students to view vkeotapes. ~ a h i e1 lists the titles of the tutorials, which serve several functions. The taDes review some ~ r i n c i ples presented in class, and they present detailed soiutions to e x a m ~ l eproblems. This videotaped tutorial method has had extens&e use in medical education as well as in engineering education, as it gives the students unlimited review capability (10,ll). Also, a t Penn State other course develop-
Course Development Program and Solutions T o increase the effectiveness of the course. we have developed three types of audio-visual aids: (1) 150 illustrations in the 35-mm slide format. ( 2 ) 14 50-minute video tutorials. and (3) a set of typed c&e notes. Each audio-visual aid served a specific function in helping students comprehend course content and in helping the instructor present new ideas in class. The objective of developing the visual aids was to make some of the inherently abstract concepts more concrete. As Brownell and Moser first indicated in 1949. teachine mathematical concepts (5),this "concretizing"'method-has the learnine effect of makine examoles relevant and understandagle. Without concrete examples, as Mayer described (6),particularly in the sciences, the students tend to memorize, thus they fail to learn conceptually to develop an effective problem-solving ability. Additionally, research that Travers did (7) on concept learning indicates that several relevant and concrete examples can sianificantlv aid the comprehension of new conckpts. For example, binding-energy and potential-energy-diagrams are very useful ideas for describing the forces that hold nuclear matter together.
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Table 1.
lltles ot the SO-Minute Vldeo Tutorials
Program NO.
Title Simple Radioactive Decay Calculations Cwpling of Two Angular Momenta OneDimensianal Particlein-Box Problem Predicting Nuclear Spins From SingleParticle Shell Madel States Calculating Alpha-Decay Constants Using the Barrier Penetration Model Applying BetaOecay Selection Rules Determinlng Gamma-Ray Mukipolaritles and Analyzing Decay Schemes Radiation Interactions: Some Example Problems Elastic Scanering Kinematics-Lab-to-Center+f-Ma55 Transtwmation Rate Equations and Nuclear Reactions Nuclear Reactions: Energy and Angular Momentum Effects Compound Nuclei Formed in Heavy-Ion Reactions Dose Calculations tor Spatially Distributed Sources Dose Calculations Continued .
1 2 3 4 5
6 7 8 9
10
11 12 13 14
ment programs in the College of Engineering have used similar television production setups successfully (12). In addition to providing help with homework, having the tapes available allows the instructor to spend less class time working example problems and homework exercises. For examnle.. manv students have demonstrated difficultv in substituting t6e correct quantities in the proper units into complicated formulas and in obtaining the correct numerical result. A case in point is the barrier-penetration expression used in the theory of alpha decay. T o work an example using the barrier-penetration expression could take most of a class oeriod. Instead, the videos remove this task from the classioom and allowthe instructor t o focus on the physics. The tapes start with an introduction that outlines what is to follow. Then, the actual working of the problem proceeds. At appropriate stopping points, the instructor presents a digression on the significance of what he has just presented. Near the end of the tutorial, the instructor summarizes the nroeram. In this summarv. he discusses the relevance of the brobem and the associated physical concept(s) or modelds) to the overall program or "big picture". The pace of these presentations appears to be exceedingly slow, but the pace is such that students can follow the presentation with pencil and paper. We also know that the itudents generally found the pace to be acceptable because many students took notes, and we are aware that students scrutinized the tapes because that is how some numerical errors were discovered. The course notes were developed over a period of several years. These notes have provided most of the information for the course because t h e text does not contain much basic information and because the students have considered the text to be inadeouate. T o improve leeibilitv, we had the notes typeset. ~ d r importantiy, e we chLgedthe notes into a suecial stvle known as a "course notes method", which was originally developed by I'ytel for a hasic engineering science course at Penn State r13). The I'vtel course notes method is one of selected omissions. In pa;ticular, at selected places, equations and/or key phrases are partially omitted so that the students can write the omitted information during the lectures. Figure 3 shows an example. One purpose of this technique is to maintain the students' attention during the lectures, but yet provide the student with a pre-lesson outline. Another Dnroose is to oreveut the students from arriving at the erroneous couclusion that, because much of the information oresented in the lectures amears to be found in the notes, thk lectures can be skipped.-(prior to developing this oarticular set of notes. the amarentlv complete set of .. notes had given rise to an attendance problem.) We mention that the alternative to providing noces in any
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Journal of Chemical Education
1. Classical Reistionship Betwen Impact Parameter, Angular momentum.
and cross section.
a. This is a schematic picture of a neutron interacting with a nucleus ofradius. , at impactparsmeter.
L.
R
(1)
L=
P is the relative momentum in C.M TheDeBraiie wave lewth,
For agiwn value of s range:
2
rh
,isgiven by:
I ,the impact parameter.
6
, lips in
Figure 3. An example of the course notes that shows the method of selected omission.
format, namely providing no notes, is not acceptable, because writine the information on the chalkboard, which cannot he obtained from a textbook and which the students must transcribe completely, is not an efficient means of information transfer. As a result, this course-notes method appears to be a workable compromise between providing a complete set of notes or providing no notes. Also, these selected omissions are systematic since the approach is not one of simply filling in the blanks. In particular, these omissions are used in sections that involve either solving simple oroblems in class. or develooine a firmre. or comuletine a schematic diagram. T o the course &es, we add& several oertiuent articles from Scientific American, and the complete package was photocopied'and made available for purchase in the bookstore. In addition to the classroom slide sets, the video tutorials, and the course notes, we decided to offer weekly or biweekly recitations (problem sessions). As no credit was~given,attendance was voluntary. In past offerings, a graduate teaching assistant usually gave the problem sessions. But we decided to evaluate the effectiveness of the more traditional out-ofclassleamine aid. namelv. the recitation. For this reason. the more experikced instr&or presented the problem sessions for this offerine of the course. Homework was tvoicallv .. . eiven " in biweekly assignments and was graded by a graduate assistant.
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Evaluation of the Program . While we were developing the program described above, we gave the nuclear and radiochemistry course during the
Table 2.
A Comparison of Responses to Selected Survey Questions
1985
1988 Dept. 1986 Aver.
ETEEM mestion.+ 1. Rate student-teacher relationship. 2. Were impatant objectives met? 3. was learning enhanced by the insbuctor's method of presentation? 4. Did the inshuctm stimulate your inteiiectval curiosity? 5. Were testing and grading procedures fair? 6. HOWinshuctor ranks with Othen as PSU? IEF WESTIONS
1. 2. 3. 4. 5.
Clarity of m e objeclives. Suitability of texUmokslmaterial. Stimulationof thinking. Course made interesting by instructor. instructor effect an student motivation.
CEM OvestionsC 4.55 1. me Course Notes heiped me follow along with new material presented in lechlre. 2.53 2. New information presented in the textbook was developed in a way that helped my learning. 3. mevideo Morials improved my understanding by allowing me to review problems in detail. 4. meslide sets seemed to b e a s a d way to present examples of new concepts and phenomenathat could not have k e n easily understwd on the chalkboard. 3.88 5. The test problems were similar to the homework problems and were therefore a fair presentation of what we should know. ~
4.31 2.38 4.28 4.13
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4.21
"IVB outof 18 questions used: ksponseo are based on a seven-hint scale. *Five oYtof 26 ~YBSIIMII donthe 1986 version: responses are bassdon afiwrpoimscale: strongly agree, agree. disagree,rmongly disagree,and undecided.lhs 1985version urntained quenions about introducingvisual aids video tutorials into me course. ~~~
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1985fall semester a t Penn State, and we administered three evaluation surveys a t the end of the course. Because we planned to compare the results of these surveys to those obtained after implementing the proeram, we used the same evaluator. Two df the surveys, the instruction Evaluation Form (IEF) and the Eneineering Teaching Effectiveness Evaluation Measure (ETEEM), a;e used commonly at Penn State. and norms are available for the ETEEM. We prepared the third, the Customized Evaluation Measure System (CEMSJ,to address specific questions about the visual aids, video tutorials, course notes, and other factors. Tahle 2 presents examples of the queitions asked by these surveys. The IEF and ETEEM are both based on the Likert scale, - ~ - the ~ which facilitates numerical comparison of different items on a given questionnaire and of similar items on different questionnaires. These evaluation methods have been analyzed and described in detail hv Canelos, Villano, and Rosenstock (4) and Canelos and ~ l l i o t(14). t The CEMS evaluates a particular set of attributes of interest, for example, the textbooks or the course notes, by asking several different questions about each attribute. Because this system is also based on aLikert scale, the responses to each set of questions can be averaged. For particular questions, the av&ages can be compared to each other on a particular CEMS, or the average responses can be compared to CEMS results obtained from different groups. Results are reported on these measures, IEF, ETEEM, and CEMS, as a mean score for each item, which is the frequency of students selecting a given option. Table 2 also presents a comparison between selected IEF, ETEEM, and CEMS resultsobtained from the course offered nrior to the implementation of the program (fall 1985) nt and aker implementation (fall 1986). ~ i ~ a r t m eaverages are presented for the ETEEM questions, and a complete summary and analysis will be published elsewhere (15). The results are striking. We see that specific queries on the effectiveness of the visual aids, tutorials, and course notes show that they were effective. Also, the problem sessions play a key role in effective teaching. Moreover, the overall ratings of the instructor and the course improved markedly. However, the textbook scores remained low. ~~
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In conclusion, the program is effective. According to the perception of the students, the value of the course has increased and remains high. These results strongly suggest that we have succeeded in teaching difficult, abstract ideas which are basic to nuclear science, to nuclear engineering underaraduates. Now, the question remains as to whether the increase in overall learnihg (after implementing the program) has been commensurate to the increase in survey scores. Standardized tests would address this question, but, unfortunately, they are not available. We did observe, however, that mean scores from some of the examinations given after implementation of the program did increase over those from examinations " eiven ~reviouslv. Although, we compared . mean scores on essentially isomorphic examinations, there is still variahilitv from vear to vear in overall classabilities and course contents. ~ h & factors e cannot yet be accounted for. Hence, we have presented a program-when considered in light of the large e n r o l l m e n t t h a t has made and will continue to make a significant impact on the art of teaching the subject of nuclear and radiochemistry. Acknowledgment
We acknowledge the College of Engineering and the Department of Nuclear Engineering for sponsoring this program. We thank Marie Hornhein for her patience in directing the video productions and Michael Halm for his assistance with the graphic arts. We thank Andrew Pytel for his assistance in developing the course notes. Also, we greatly appreciate assistance from Ray Nix of Los Alamos National Laboratory, who provided some illustrations of the fission process. Llterature Cited
1. ACS Directory ofDroduote Research: American Chemical Society: Washington,DC, 1984. 2. Friedlander,c.;Kennedy,J. w.;Maeias,E.S.;Miller,J.M.Nucl~orondRodiochemi~~ f r y 3rded.; Wiley:New York,1981. 3, Catrhen,G.L.:Witzig, W. F.Eng.Edu 1986, 77,120. 4. Canelor. J.;ViUana, M.:Rosenstoek, E. F~onfiersEduc.Roe. 1984.14,499. 5. Brownell. W. A.; Mmer. H. E. Duke Uniu. ROS.Stud. Educ. 1949,8,1. 6. Mayer, R.D. Thinking and Problem Soluing; Scott, Foresmsn: Glenview, 1L. 1977. Volume 65
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7. Trsuers,R M. W. Erssnliols o f h r n i n g , 4th ed.; Maemillan:New York, 1977. 8. See, forersmpls, Brandt, S.; Dahmen, H. D. The Picture Book o/Quonlum Meehanirs: Wilcy: NcwYork, 1985. 9. Trsbsslio,T. R. J.Erp.Psyeho1. 1563.65.398. lo. Canelm. J.: Mollo, R. RontiorsEdue. Conf. Proe. 1986.16.338.
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11. Meter, W.; Csnelm, J.; Mollo, R.: Kmfaek. D. Compendium Uses Toleuision Eng Educ. 19811.3.241. 12. Canelm,J.:Carpenter, L. Not. Issues Higher Educ. 1384.14.84. 13. Pytei, A. Not. Issues Higher Edue. 1984,14,322. 1 4 Canelm,J.; Ellidt. C. Frontiers Educ. Proe. 1985.15.77. Csneloa. J., to be published inEng. Ed=. 15. Catehen, 0.:
