Demonstrations

Conductivity of Water

Code Number :	5D30.10
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. Further information regarding legal liability in use of demonstrations and labs will be found on the web site Injuries in School/College Laboratories in USA. The University of Iowa Disclaimers: University of Iowa Disclaimer All Rights Reserved..
Condition :	Good
Principle :	Solution Conductivity
Area of Study :	Electricity and Magnetism
Equipment :	Battery Jars (2), Carbon Electrodes on Plastic Support, Switch, Light bulb, Power Cord, Salt, Acid (Hydrochloric, Sulfuric), Stirring rod.
Procedure :	Place water that has been run through the filters into the battery jars so that the electrodes are sufficiently submerged. There should be no observed conductivity as shown with the light bulb. Pour in salt and the light will start to glow. This will take a lot of salt as it takes time for the salt to dissolve and diffuse. For this reason the acid may be the better choice in some cases as this problem does not occur. Caution: Avoid acid burns and always unplug the power when moving the electrodes.

References

Deborah F. Buffum, "Carbon Electrodes Improvised," TPT, Vol. 35, # 5, p. 315, (May 1997).

Ef-1: Freier and Anderson, A Demonstration Handbook for Physics.

E-260: "Pigtail Socket - Salt Solution," DICK and RAE Physics Demo Notebook.

70: "Electrolytic Titration," Chemical Demonstrations, Vol. 2, p. 132.

Neil. A. Downie, "Electrolystor Amplifier", Ink Sandwiches, Electric Worms and 37 Other Experiments for Saturday Science, p. 160.

Mail Questions and Comments to: Dale Stille