Disclaimer:

Reprinted by permission of Dick Berg, University of Maryland, for use on this website.

The demonstrations contained and referenced herein are listed for the purposes of cataloging and describing physics demonstrations which should be conducted only under the direction of a trained instructional support professional or physicist. These demonstrations are not presented for the purpose of being conducted by persons unconnected to this Facility and/or persons not consulting with or being supervised by the recognized instructional support professional or physicist and his/her staff. The University is responsible only for those demonstrations carried out using its own equipment using established safety and scheduling policies, and bears no responsibility for those choosing to use this source material for their own purposes. All demonstrations described and contained herein are public domain, and can also be found in reference materials in libraries, bookstores, and electronic sources.

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The felt will settle out some but not enough to affect the demonstration. Pour the mixture into a petri dish and add the desired bars or point sources. Touch the wire electrodes to these and apply the voltage from the 5 KV power supply. The felt will align itself to show the lines of force around the bars or points. Use only as much voltage as necessary and then turn it off as boiling and worse will come about if the voltage is left on. 

There is a set of 6 Mustard Seeds In Oil Slides that show these lines of force also that may be used in conjunction with this demo.

NOTE:  Use wool felt, not synthetic felt.