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Introduction |
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We are in the midst of a project to place on the Web video clips of all of the physics demonstrations used by the Wake Forest University Department of Physics. The principal goal of this project is to make the classroom demonstration available to students for review and additional study.
Not all science classes include any science. Many present only science results. Science is a process, a way of coming to understand things about the universe the we did not understand before. When we teach Newton's Laws or Bernoulli's Principle, we are not teaching science: we are teaching results of science. The discovery of Newton's Laws and Bernoulli's Principle was science.
So how can we teach science to introductory physics students? One way is through classroom demonstrations. Such demonstrations are quick experiments than can be done in the classroom. Students can collectively observe, model, predict, and observe again; that is, they can participate in science right in the classroom.
This is why many physics faculty use so many demonstrations. However, students are traditionally put at a disadvantage when demonstrations are central to the course. Demonstrations are rarely available for subsequent review. Many happen very quickly, and students have little opportunity to look again or to look more closely.
The advent of the web and inexpensive technology for publishing videos eliminates this problem. Demonstrations can be videotaped and made available to the class via the Web. Students are free to review as often as they like, stopping the video, advancing it in slow motion if they like.
Since beginning the project, we have found additional uses for the videos.
The current participants in this project are
Susan Boling, former Student Technology Advisor and now with Microsoft, digitized all the initial video clips and placed them on the web. We also thank Machele Kindle and David Sturm, both former laboratory managers, for their significant contribution to this project.
MPEG II and the higher bandwidth RealVideo clips are in development. You can take a peek at our efforts to improve quality at our Video Comparisons page. The best page to view all the formats in is the streaming page. The older low bandwidth RealVideos and the MPEG I clips are accessible in two locations:
A few typical videos can be accessed from the table below.
| Tablecloth pull | Pull a tablecloth from beneath a dinner setting. |
| Curve ball | A ball thrown with spin curves. |
| Simultaneous fall | The device drops two balls simultaneously. One is given both vertical and horizontal components. The other simply falls. |
| Monkey-hunter | A gun is aimed directly at a higher target. The target releases and falls at the same time the gun is fired. |
| Revolving pail of water | Water stays in the bucket while the bucket is swung overhead. |
| Rotating person and masses | A person stands on a rotating platform holding two masses. |
| Rotating person with bicycle wheel | A person mounts a lazy susan with a spinning bicycle wheel. |
| Falling chimney | Watch the end of a stick fall faster than g. |
| Bed of nails | Try to walk or pop a balloon on a bed of nails. |
| Wave machine | A wave machine illustrates wave propagation, interference, and standing waves. |
| Electromagnetic launcher | An electromagnet with an iron core that extends into the air is used to launch or suspend metal rings. |
| Van de Graff | A Van de Graff electrostatic generator brings lightning to the classroom. |
These movies are being displayed in both MPG and RealVideo format. The RealVideo movies are not as high a quality, but they are MUCH smaller. To view them, you need to install a free plug-in for your web browser available at http://www.real.com. In some cases, this format is good enough for your purposes. Other times, you may just want to use this as a quick preview before deciding whether to view the higher quality file with the longer transfer time.
We are in the process of transferring these files to a MediaHawk streaming server. Until this is complete, the video will not begin playing until the entire file is downloaded.
The videos were filmed mostly over fall and spring semesters 1997-1998. They were all shot in standard VHS with a camcorder that was several years old. You will notice considerable improvement in later videos as we learned the importance of better lighting.
The VHS videos were digitized usings a Broadway video capture card. Accompanying software created the MPG and RealVideo formats. Users with high bandwidth connections generally prefer MPG, while those using modems prefer RealVideo.
New videos are being shot with a Sony V310 digital camcorder. The image quality difference is remarkable. We have also acquired two banks of halogen floods for better lighting. Front lighting is important! These are inexpensive units purchased for around $30 at a home improvement store, but they do a wonderful job. Finally, we have begun using a blue sheet as a backdrop, which gives better contrast to to flying balls, etc., than the whiteboard of earlier videos.
We welcome comments, suggestions, ideas, and collaborations. If you care to share your own video clips, we will provide proper attribution.
We would like for this collection to become a resource for other physics departments and for high school teachers. If you wish to use these in your own courses, please just drop us a note letting us know how you are using them.
Sends comments on this page or
our demo movies to matthews@wfu.edu.
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