North Carolina Section of the American

Association of Physics Teachers








5th Annual Spring Meeting

Davidson College

Davidson, NC  28036

March 17-18, 2000




Friday evening, March 17


6:00 – 9:30     Vendors                                                Dana 111 and Dana 127


6:00  - 8:00     Registration                                           Dana Lobby


7:30 – 8:30     Public lecture: Tom Greenslade (Kenyon): Learning from the Past: The American 19th Century Physics Course

                                                                                    Dana 146


8:30 – 9:30     Reception and Social                             Dana 111 and Dana 127


9:00 - 10:30    PTRA make-and-take workshop          Dana 126


9:30 - ????      Two-year College Physics Teachers Alliance Meeting – Best Western Motel meeting room


Saturday, March 18


8:00 – 12:30    Registration                                           Dana Lobby


8:00                 Coffee                                                  Dana Lobby


8:00 – 2:00      Vendors                                                Dana 111 and Dana 127


Parallel sessions                                                            A: Dana 146; B: Dana 153


8:30 – 8:45       A. Narayanan (Savannah State): Raman Spectroscopy – Historical and Modern Renascent Phase

                         B. Michael (East Lincoln High): Reach for the Stars with PowerPoint


8:45 – 9:00       A. Risley (NC State): WebAssign’s First Annual User’s Group Meeting

                         B. Heafner (Catawba Valley CC): Matter & Interactions: A New Introductory Physics Curriculum


9:00 – 9:15       A. Saul (NC State): Adapting research-based collaborative-learning activities for the SCALE-UP curriculum

                         B. Wetli (Wake Tech CC): Throwing Polynomial Fits


9:15 – 9:30       A. Dancy (NC State): Using Animations for Conceptual Assessment

                         B. Collins (Warren Wilson College): Video and Video Capture Applications in Physics Labs


Plenary talk


9:30 – 10:30      Arnold Arons (Washington): Teaching Energy Concepts In Introductory Physics Courses
                                                            Dana 146

10:30 - 10:50     Morning Break                                   Dana 111 and Dana 127


Mid-morning session                                                     Dana 146


10:50 - 11:10   Winters (NC School of Math and Science): Educational Technologies for Physics Teachers


11:10 - 11:30   Belloni (Davidson): Physlets and Just-in-Time Teaching


11:30 - 11:50   Junkin (Erskine): Web-based Software to Enhance Instructor-Student Interaction


11:50 - 12:10   Bennett (UNCA): E-learning Enhancements for Introductory Physics


12:10 - 12:30   Turner (Guilford County Schools): Learning Anytime Anywhere Physics


12:30 - 1:15     Lunch                                                    Commons

                        Elections for TYCPA will be held during its lunch meeting on Saturday


1:15 - 2:00       NCS-AAPT Business meeting               Commons


Afternoon Session                                                         Dana 146


2:15 - 2:30       Turner (Clemson): Physics Fun with Magnetic Toys


2:30 - 2:45       Greenslade (Kenyon): Wave Machines and Harmonographs


2:45 - 3:00       Bryant (Sandhills CC): Simple, Easy and Inexpensive Demonstrations of not-so-simple Concepts




3:00 - 5:00       Physlets                                                 Dana 127

                        Nuclear Science Techniques                  Dana 111

                        Physics in Music                                    Dana 126




Friday, March 17, 2000



6:00-8:00      Registration – Dana Science Building, Lobby



7:30-8:30      Public Lecture, Dana 146


                    Learning from the Past: The American 19th Century Physics Course


Tom Greenslade, author of many Physics Teacher articles on 19th century equipment, Department of Physics, Kenyon College, Gambier, OH 43022, (740)-427-5368, (740)-427-5237 (fax),


We all owe a great debt to nineteenth century physics. Not only the way in which we teach physics, but the very subject comes from the foundation of classical, nineteenth century physics. The first half of the talk will discuss the curriculum in the middle of the century and the way that physics fitted into it, the textbooks, the students and the faculty. This will be followed by a discussion of high vacuum and high voltage, which are used to produce many of the phenomena of twentieth century physics. The talk will be copiously illustrated with lantern slides.



8:30-9:30      Reception and Social – Dana 111 and Dana 127

                    Sponsored by Prentice Hall


9:30-????      Two-year College Physics Teachers Alliance Meeting – Best Western Motel Meeting Room



9:00-10:30     PTRA Make-and-Take Workshop – Nina Morley Daye and Chuck Britton, Dana 126



Saturday, March 18, 2000



8:00-12:30    Registration – Dana Lobby


8:00             Coffee – Dana Lobby


Parallel Sessions: A – Dana 146  and  B – Dana 153


Session A - Dana 146


8:30-8:45     Raman Spectroscopy-Historical and Modern Renascent Phase


V. Anantha Narayanan, Physics, Savannah State University, P. O. Box 20473, Savannah, Georgia 31404, (912)-927-9330, (912)-927-9330 (fax),


The author will give a brief historical account of Raman Spectroscopy and techniques used by him in his graduate days during sixties and give the renascence of Raman Spectroscopy in the last two decades due to spectacular advancements in instrumentations.  These have made Raman Spectroscopy, the preferred and in some cases the only feasible method in many branches of sciences.  Some of the author's work in both phases of Raman Spectroscopy will be briefly discussed.


8:45-9:00     WebAssign's First Annual User's Group Meeting


John S. Risley, Department of Physics, North Carolina State University, Raleigh, NC 27695, Department of Physics, North Carolina State University, Room 11, BOM Building, Raleigh, NC 27695-8202, (919)-515-2524, (919)-515-2682 (fax),


WebAssign is a versatile web-based homework grading system that is attracting huge numbers of users. Many types of questions can be used in WebAssign. Because of the huge number of innovations currently being tried with WebAssign, the 1st user's group meeting is being organized to be able to share some of these ideas and to learn more about WebAssign from the programming staff. During this talk I will outline some of the new innovations and give an outline of what you can expect at the upcoming meeting on May 5-6, 2000 at the NCSU McKimmon Center.

For more info, visit



9:00-9:15     Adapting research-based collaborative-learning activities for the SCALE-UP curriculum*


                        Jeff Saul, Robert J. Beichner, David W. Abbott, Duane L. Deardorff, and Rhett J. Allain, Physics Department, North Carolina State University, Box 8202, Raleigh, NC 27695, (919)-515-9767, (919)-515-2682,


                        The Student-Centered Activities for Large Enrollment University Physics (SCALE-UP) Project is studying how to establish a highly collaborative, hands-on, multimedia-learning environment for classes of up to 100 students.  We are currently in Phase 2 of the project, developing and evaluating the curriculum in a technology-rich, group-oriented classroom for 50 students and 2 instructors before implementing SCALE-UP in larger classes.  We are having some success at adapting student-group activities from successful research-based curricula like Workshop Physics, Tutorials in Introductory Physics, and Cooperative Group Problem Solving designed for use in smaller classes (15-30 students).  This talk will focus on the issues of adapting Tutorial activities to this classroom environment.

*Supported by FIPSE grant #DOE-P116B71905, Hewlett Packard, and NSF grant #DUE-9752313


9:15-9:30     Using Animations for Conceptual Assessment


Melissa Dancy, Department of Physics, North Carolina State University, Box 8202, Raleigh, NC 27695, (919)-515-9767, (919)-515-2682 (fax),


The questions on the Force Concept Inventory have been rewritten, using the Physlet Animator, by replacing static pictures and descriptions of motion with computer animations.  Data has been collected which allows for comparison between student responses to the traditional and animated versions of the FCI.  This talk will focus on early results of this project.



Session B - Dana 153


8:30-8:45     Reach for the Stars with PowerPoint


Debbie Michael, East Lincoln High School, 6471 Hwy 73, Denver, NC 28307, (704)-483-5681, (704)-483-6751 (fax),


Want to get high school students interested in conducting research?  Try having students present the information in a PowerPoint presentation.  This is an excellent way to integrate technology into science classes as well as helping students prepare for the job market.


The basics of the PowerPoint program are taught to the high school students in one ninety-minute period.  Students are then taken to the library to conduct research on desired topics of their choice with teacher approval.  Students are given guidelines and expectations of product produced.   Time in computer lab is reserved for students to complete the project.


Teachers will be given ideas on implementation of this project.  Pitfalls will be discussed and strategies that are working will be discussed.  This is currently working well in my Astronomy and Physical Science classes.  Students are now begging to return to the computer lab to work on projects.  Get your students excited about science!


8:45-9:00     Matter & Interactions: A New Introductory Physics Curriculum


Joe Heafner, Catawba Valley Community College, 2550 Highway 70 SE, Hickory, NC 28602, (828)-327-7000, ext. 4246, (828)-327-7276 (fax),


                        Matter & Interactions is a brand new approach to the introductory physics course by Bruce Sherwood and Ruth Chabay, both of the Center for Innovation in Learning at Carnegie Mellon University. Traditional kinematics is done away with, and the emphasis is on fundamental Newtonian dynamics with certain relativistic modifications incorporated as needed. Energy conservation, momentum conservation, and angular momentum conservation are presented as the background from which a broad range of physics can be derived. The approach leads from classical dynamics into elementary quantum mechanics, thermodynamics, and statistical mechanics. In this presentation, I will summarize this non-traditional approach and share my experience in implementing it here at CVCC during the 1999-2000 academic year. If time permits, I will also demonstrate the cT programming language, with which students create simple computer models to illustrate physical principles.


9:00-9:15     Throwing Polynomial Fits!


                        Denise M. Wetli, Wake Technical Community College, 9101 Fayetteville Rd., Raleigh, NC  27603-5696, (919)-662-3540, (919)-779-3360 (fax),


                        Without knowing physical laws beforehand, we sometimes have students investigate phenomena and ask them to develop a model.  Often, what results is students report that a 4th order polynomial fits "linear" data since its correlation coefficient is the highest.  Students’ use of electronic curve fitting programs has brought out the need to create exercises in finding "meaningful" models to data.


9:15-9:30     Video and Video Capture Applications in Physics Labs


                        Donald F. Collins, Warren Wilson College, Asheville, NC  28815,

(828)-298-3321, (828)-299-4841 (fax),


                        The video camcorder with auxiliary software (image capture, VideoPoint) is an excellent tool for examining, demonstrating, and making measurements in many physics laboratories and demonstrations, thus proving high utility along with oscilloscopes, computers, and air tracks.  The cost of video equipment has decreased dramatically, making the equipment widely accessible.  High school and college teachers should give a very high priority to equipping their labs with video equipment including image capture. Examples of experiments enhanced by homemade video will be shown, especially experiments involving rapid transient motion phenomena, small-scale experiments, and microscopic experiments.


Plenary Talk – Dana 146


9:30-10:30   Teaching Energy Concepts in Introductory Physics Courses


                        Arnold Arons, author of many physics teaching articles and books, Department of Physics and Astronomy, University of Washington, Box 351560, Seattle, WA 98195-1560, (206)-523-5251 (home), (206)-685-0635 (fax),


                        Although the so-called "Work-Energy Theorem", derived by integrating Newton's Second Law with respect to position, provides plausible motivation for developing the energy concepts, this theorem has extremely limited validity. It applies only to particles (or center of mass displacement of extended objects), and it is not a valid energy statement about situations involving frictional forces, displacement of deformable bodies (e.g. our own jumping vertically upward or pushing ourselves away from a wall), or systems consisting of more than one particle. To generate the full range of energy concepts correctly, one must go beyond this theorem and introduce the concept of "internal energy." Ways of doing this correctly and effectively in introductory courses will be suggested.



10:30-10:50   Morning Break – Dana 111 and Dana 127

                    Sponsored by Prentice Hall

Mid-morning Session – Dana 146


10:50-11:10  Educational Technologies for Physics Teachers


Loren Winters, North Carolina School of Science and Mathematics, 1219 Broad Street, P.O. Box 2418, Durham, NC 27715, (919)-286-3366 x413,  (919)-286-5960 (fax),


                        The North Carolina Department of Public Instruction has sponsored the author for the past 2 years in a project to investigate various educational technologies and support their use by North Carolina science teachers.  This talk will present examples of the use of several new technologies, including digital video using the mini-DV format, authoring of interactive, web-based problems using a Java 2 applet, and audio-video streaming.


11:10-11:30  Physlets and Just-in-Time Teaching: From Introductory to Advanced Physics Courses


Mario Belloni and Wolfgang Christian, Department of Physics, Davidson College, Davidson, NC 28036, (704)-892-2320, (704)-892-2894 (fax),


Java-based interactive physics problems, Physlets (small Java-based interactive physics applets), have been incorporated throughout the introductory physics series here at Davidson College. They have been used as in-class exercises, Just-in-Time Teaching (JiTT) Warm Ups and Puzzles, lab preparatory exercises, and extensions to the "traditional" problem sets.  We are currently adapting, writing, and teaching with new curricular material using Physlets and JiTT in our advanced courses such as modern physics and electromagnetic theory. Specifically, we are developing curricular material that bridges the gap between introductory physics and more advanced courses. This progression follows the increased functionality of Physlets that have been greatly extended through the introduction of compound objects and inter-applet communication (to name just two recent additions). We will discuss these ever changing developments with an emphasis on the new Physlet-based curricular material for advanced courses. Additional information can be found at


11:30-11:50  Web-based Software to Enhance Instructor-Student Interaction


Bill Junkin, Physics, Erskine College, #2 Washington St., Due West, SC 29639, (864)-379-8822, (864)-379-2167 (fax),


Web-based (HTML) software will be introduced which enhances student learning by increasing student involvement and instructor-student interaction. An interactive or polling software has been developed which facilitates the pedagogy of “Peer Instruction” developed by Eric Mazur (Harvard University). A template for preparing pre-class questions has also been developed which aids in the “JiTT” (Just-in-Time Teaching) developed by Novak and Garvin (IUPUI), Patterson (Air Force Academy), and Christian (Davidson). Both of these software programs which I wrote are available for free for educational use. The recently developed pedagogies which they support have been used effectively in physics and other disciplines at the high school and undergraduate level.  Preliminary results of using some of this software with traditional introductory physics labs are especially promising. The software, along with the evidence of increased student learning, will be presented.


11:50-12:10  Recent E-Learning Enhancements for Introductory Physics


C. A. Bennett, Department of Physics, UNC Asheville, Asheville, NC 28804, (828)-251-6476, (828)-251-6397 (fax),


Several enhancements have recently been incorporated into a calculus-based introductory physics course, some of which were enabled by the adoption of WebCT for classroom facilitated Web-based instruction.  For example, we have followed Mazur by utilizing both reading and concept quizzes.  Reading quizzes (multiple-choice, each question drawn from a separate pool, feedback provided after submission) are timed, single-attempt tests that are due before related classroom discussion.  Concept quizzes, on the other hand, are untimed, unlimited-attempt tests with no feedback until after the period of availability (usually one week).  Students are encouraged to share ideas on concept tests either in person or via discussion forums.  Solutions for the concept quizzes are posted automatically at the instant the quiz expires, and only then is class time used to discuss the results.  Other course enhancements include use of the entire Mechanical Universe series via streaming video, and a Web application for administering homework ( which, although independent of WebCT, has been transparently integrated.



12:10-12:30  Learn Anytime Anywhere Physics (LAAP):  Guided Inquiry Web-Based Laboratory Learning


Mike Turner, Guilford County Schools, Harol Hoffman & Jerry Meisner, UNCG; 120 Petty Science Building, Greensboro, NC  27402-6170, (336)-334-4217,   (336)-334-5865 (fax),;;


The Extended Physics Community (EPC) Consortium will author Learn Anytime Anywhere Physics (LAAPhysics: Members of the EPC Consortium currently include: the University of North Carolina Greensboro (lead institution), partnering with North Carolina A&T State University, Davidson College, the NC Department of Public Instruction, North Carolina public school physics teachers; North Park University and webslingerZ, Inc.


LAAPhysics will provide both synchronous and asynchronous learning experiences for an introductory, algebra-based course for undergraduate students (including high school AP physics students), those seeking career changes, and preservice and inservice teachers.  We will use Java technology to develop and build a complete online physics laboratory learning environment comprised of virtual lab equipment and apparatus applets (laaplets), associated curriculum modules, a virtual collaborative learning environment through the use of Latent Semantic Analysis as well as student assessment components. 


LAAPhysics is tied to existing physics curriculum materials from the best pedagogy that has emerged from recent research in physics education and as such will provide a distance learning experience in the sciences for those unable to obtain such experiences in traditional college laboratory settings.  Interactivity between client machine and server side databases will permit just in time analysis (JITA) for immediate feedback and guidance as well as for assessment of student performance. Additional assessment instruments will be used to compare LAAP students with traditional in situ students. 


12:30-1:15    Lunch – Commons

                    Elections for TYCPA will be held during its lunch meeting on Saturday.


1:15-2:00      NCS-AAPT Business Meeting – Commons



Afternoon Session - Dana 146


2:15-2:30      Physics Fun with Magnetic Toys


Ray Turner, Clemson University, Dept. of  Physics, Clemson, SC 29634-0978, (864)-656-5321, (864)-656-0805 (fax),


Teachers know that physics is fun. But perhaps we can also convince our students of this through the use of ordinary children’s toys as physics demonstration devices. There are a variety of magnetic toys available that can be used to demonstrate the simplest magnetic forces as well as more sophisticated applications of Maxwell’s Equations. Some old toys and some new ones will be shown including a Giant Horshoe Magnet, a Magna-Trix floating magnet, a Rainbow Spinning Wheel, Robby the Circus Seal, a Snake and Top, a Revolution, a Magna Swing, a Levitron, and several Kinetic Toys. Physics can be fun with toys.


2:30-2:45     Wave Machines and Harmonographs


Tom Greenslade, Department of Physics, Kenyon College, Gambier, OH 43022, (740)-427-5368, (740)-427-5237 (fax),


The teacher of physics in the nineteenth century had a wide range of demonstration apparatus available to show the phenomena of simple harmonic motion and waves. Toward the end of the century, harmonographs were devised to show how simple harmonic motions could be combined in various complex ways.  Slides of a number of examples of wave machines and harmonographs will be shown.


2:45-3:00     Simple, Easy, and Inexpensive Demonstrations of not-so-simple Concepts


Arthur Bryant, Sandhills Community College, 2200 Airport Rd., Pinehurst, NC 28374, (910)-947-5835,


The apparatus used to demonstrate rotational inertia and angular momentum is usually complex and costly. A simple large rotating stool assembly made with a used auto rear wheel hub can be constructed and used for demonstrations and experimentation.  In addition, a low-cost pendulum system will be used to illustrate supplementary rotational inertia concepts.  Another high-cost apparatus that is usually purchased and not constructed is one that is needed to demonstrate motion on a frictionless surface. A near-frictionless surface can be constructed using small low-cost rollers (material conveyers) and used to demonstrate various action-reaction pairs.



3:00-5:00     Workshops


PhysletsWolfgang Christian and Mario Belloni, Davidson College - Dana 127


Participants will learn how to use interactive Java applets to deliver interactive media-focused problems and other curricular material to students. Example problems, Java applets, and a sample website will be distributed. Web technology in support of Just in Time Teaching will also be presented. See for more details and examples of curricular materials.

Note: We will be using Windows-based (Windows NT) computers during this workshop.

Nuclear Science TechniquesRandolph Peterson, University of the South - Dana 111


This two-hour workshop provides an excellent opportunity for science instructors interested in developing a nuclear lab course together with experienced teachers wishing to review the latest equipment and techniques.  The workshop covers all aspects of the nuclear science laboratory and is divided into two parts for introductory and advanced level instruction.


The first part of the workshop focuses on the use of Geiger-Mueller Counters ideal for high school and beginning college level instruction.  Demonstrations included properties of radiation, radioactive decay, inverse square law, resolving-time correction and several demonstrations using samples collected by the students. The use of computers for data collection and spreadsheets is covered in some detail to aid students in data analysis.


After a short break, the second part moves to advanced spectroscopy experiments on PC and Macintosh computers using multichannel analyzers and scintillation detectors. This session covers system setup, energy, calibration, spectral analysis of commercial radioisotopes and multichannel scaling for counting statistics and half-life experiments. Environmental samples are be collected during the workshop and analyzed for radioactive content. Samples of commonly available materials containing radioactivity are analyzed and discussed. Data analysis using spreadsheets and curve fitting with peak deconvolution using mathematical software is included as part of the demonstration.


                        Physics in MusicDan Boye, Davidson College - Dana 126


The harmonic series, defined by a simple linear relation, is ubiquitous in music. It can be used to derive the selected pitches found in music from many cultures. In addition, all instruments that generate a well-defined pitch do so by resonating frequencies that comprise a harmonic series. This workshop will use simple, hands-on demonstrations that can be easily integrated into classroom exercises, as well as readily available computer demonstrations to explore the harmonic series.




Watch our web page for information:


In particular, if you missed a meeting and didn’t read about it in the “Announcer”, you can find the highlights of the meeting on this web page along with the Constitution, a membership application, a current list of officers, and other useful pieces of information.


Prizes and Awards

As there will be prizes for the best undergraduate student paper, the best graduate student paper, and the best pedagogical paper, please keep notes and make recommendations to any section officer to aid in their choice at this meeting.

Karl Mamola is chair of the Awards Committee and has several candidates nominated for the Walter C. Connolly Award (“An award to recognize outstanding pre-college teachers in the Section.”)  We thank our sponsors for contributing to support these awards.  Donations to this award fund are tax deductible and appreciated.  Make your check out to “NCS-AAPT” and place “Walter C. Connolly Award” in the “For” section.

Your mailing label

If your mailing label had “2000” or greater, your dues are paid up.  Otherwise please send a check for $5.00 for each deficient year to the Secretary-Treasurer to bring your membership up-to-date and help ensure the viability of the Section.  You can check at the registration desk if you don’t remember your year.


E-mail addresses


If you did not receive an e-mail message about this meeting and you have access to

e-mail, please send a note to John Hubisz at with your correct e-mail address.  You may also give it to someone at the registration desk.


Nominations -Election


Nominations are being sought for the 4-Year College/University member-at-large, Vice-President, and Secretary-Treasurer for the election at this meeting.  Deva Sharma of Winston-Salem State and Rajive Tiwari of Belmont Abbey College have been nominated for Four-year College/University Representative; Prabha Ramakrishnan of Carteret Community College has been nominated for Vice President; and John Hubisz and Mary (Avery) Putnam have been nominated for Secretary-Treasurer.  A “Call for Nominations” will be made from the floor at the business meeting and then voting will take place.


Future Meetings


The Fall 2000 meeting of NCS-AAPT is a joint meeting with SACS-AAPT.  This meeting will be held October 13-14, 2000, at the campus of USC-Spartanburg in Spartanburg, SC.  Make your plans to attend now.


The Spring 2001 meeting of NCS-AAPT will be held at the North Carolina School of Science and Mathematics in Durham, NC.



AAPT Officers 1999-2000


Immediate Past President: Hugh B. Haskell

244 Beachers Brook Lane, Cary NC 27511, (919) 286-3366 Day, (919) 467-7610 Eve., FAX (919) 286-5960,  OR HASKELL@ODIE.NCSSM.EDU


President: Denise Wetli

Wake Technical CC, 9101 Fayetteville Road, Raleigh NC 27603, (919) 662-3540,


President-Elect: Chuck Bennett

Physics Department, University of North Carolina - Asheville, Asheville NC 28804, (704) 251-6047 Office, (704) 251-6397 FAX,


 Vice-President: Helen C. Briggs

Lenoir Rhyne College, Physics and Earth Science Dept., Box 7403, Hickory NC 28603, (828) 328-7263 Office,




Secretary-Treasurer: John L. Hubisz (1996-2000)

1604 South Salem Street, Apex NC 27502-7251, (919) 515-3182 Day, (919) 362-5782 Eve. FAX (919) 515-7331, OR


Section Representative to AAPT: Karl C. Mamola (1999-2003)

Department of Physics, Appalachian State University, Boone NC 28608, (704) 262-2440 Day, (704) 264-6276 Eve, FAX(704) 262-2049




4-Year College/University: Hildelisa Hernandez (1997-2000)

Department of Physics, UNC @ Wilmington, Wilmington NC 28403, (910) 395-3465 Day, (910) 350-1183 Eve,


2-Year College: J. Aaron McAlexander (1998-2001)

CPCC, Department of Physics, PO Box 35009, Charlotte NC 28235, (704) 342-6447 Day, (704) 536-6287 Eve,


Pre-College: John Kolena (1999-2002)

Department of Physics, Duke University, Box 90305, Durham NC 27708-0305, (919) 286-3366 Office, FAX: (919) 286-5960,



Addison Wesley Longman

American Association of Physics Teachers

Bernard O. Beck & Co.

Davidson College

Harcourt Brace/Saunders College Publishers


North Carolina State University

Physics Academic Software

Prentice Hall

Spectrum Techniques

Vernier Software and Technology


John Wiley and Sons


Local Committee


Dan Boye

Larry Cain

Wolfgang Christian