SECTION ONE: INTRODUCTION FOR WORKSHOP LEADERS

The study of electrostatic phenomena has fascinated people since Greek times. Today, it is an important area of study in both science and technology. The large intrinsic strength of the electrical interaction means that relatively large forces can be obtained with relatively small charges, allowing students fairly direct experience with a fundamental force. The “magical” nature of the phenomena are exciting, but caution should be taken not to let the fun eclipse the physics. It is my belief that careful design of student activities in electrostatics can build the deeper fun of understanding nature through experiment. An excellent historical example lies in the work of Benjamin Franklin, who describes experiments and experiences which were clearly entertaining, but which had an underlying serious purpose, and led Franklin to a viable model of electrostatic phenomena. An excellent teaching unit by Rodney LaBrecque based on Franklin’s experiments is available in the AAPT Electrostatics Workshop (Morse, Toth & LaBrecque, 1991), and reprinted as Appendix B.

This book is not intended as a textbook, but as a resource and workshop guide. Section 2 gives some background information, but is not intended to replace the presentation in textbooks. The activities and demonstrations in Sections 3 and 4 do not constitute a comprehensive sequential development, but are intended to be adapted and used as needed by teachers to fit their curricular needs. Two examples of the use of these activities in curricular packages are given in Appendices A and B, and these may serve as models in developing your own sequence, or be used or adapted to your needs.

The extensive use of plastics in disposable containers makes it inexpensive and easy to construct a variety of electrostatics equipment so that every student can experiment with static charges and the fields they create. Constructing and experimenting with these simple devices makes a good workshop activity for teachers from elementary school through high school. The materials required are low in cost and can be readily obtained at grocery and hardware stores. Most of the projects require only simple tools, such as scissors. Only one of the projects would require the use of a jigsaw and a drill.

The philosophy guiding the development of this workshop is that students should have as much hands-on and minds-on experience as possible with phenomena, that equipment should be as inexpensive as possible consistent with function, and that the equipment that students use should work as well as possible to illustrate the phenomena clearly. Nonetheless, electrostatic events happen suddenly, and humidity and dirt can provide conducting paths which are unseen. There is no substitute for careful and repeated observations, with clean and dry equipment.

There is more than enough material here to run a workshop which lasts all day. A reasonably complete exploration of the topics in the workshop and the two student activity modules might take several days to a week or more. However, a one day or half day workshop should be sufficient to establish the principles so that the participants can try the student modules out themselves.

Sufficient to introduce the material to a group, although not long enough for a thorough experience with all the activities. Concentrate on Section 3, perhaps working on the following sections of lab activities:

• LA 1:

  Charged tapes

• LA2:

  Pith ball electroscope, Soda can electroscope

• LA3:

  The electrophorus

• LA5:

  The electrostatic hydra

• LA6:

  Neon bulbs, Investigating electrophorus charging

• LA8:

  Plastic cup or film can Leyden jar

You may choose to demonstrate but not have participants build the generators and electrostatic motor from Section 3, and perhaps the smoke precipitator and ion wind generator from section 4

Have materials and tools prepared and laid out in advance, and have enough space for people to work in comfortably. Review the headings for the activities to see which materials you will need.

Concentrate on Sections Three and Sections Four. Participants can build most of the devices in Section 3, Lab Activities 1-8, and build the electrostatic motor. In section 4 they should build the smoke precipitator, ion wind generator, and perhaps the Faraday Ice pail, and see the demonstration of the flexible capacitor. Reserve some time for discussion and to look at and try some activities from Appendix B.

For a two day workshop, participants should do as much as possible from Sections 3 and 4 and sample appendices A and B. As time and inclination allow other parts of the package can be explored. If computers are available, the Electric Field Hockey game is a good diversion. In a longer workshop, there may be time to pursue some of the references, see some of the video segments and try some of the competitions.

Electrostatics investigations work best in clean, dry air. Reasonable success has been had with this workshop in non-ideal weather. Air-conditioning can be used to reduce the humidity, and an electric hair dryer can be used to dry the materials before use in humid areas. As with all experiments, you should try these yourself under the conditions in which you expect to use them before having participants or students try them.

For a moderate size group you will need:

If you wish participants to build the generators you will need additional materials. Consult the materials lists in Section 3 LA-9, and LA-10.

The Flexible Capacitor Demonstration, Page 4-5 requires 0.25 mil Aluminized Mylar. See the materials description in that section.

You should also have samples of the devices already prepared as examples for participants to look at.