Set up for Conductivity of Water Demo
Conductivity of Water Demo

 

Code Number: 5D30.10

Demo Title: Conductivity of Water

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), and Stirring Rod, Conductivity Probe (homemade).

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.

The homemade conductivity probe can be used to observe the effect of ion concentration to conductivity in solutions.

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.
  • Bassam Z. Shakhashiri, "9.31 - Electrical Conductivity of Liquids", Chemical Demonstrations, Vol. 3, p. 326.
  • 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.
  • Bobby Mercer, "Energy Drink Tester", Junk Drawer Chemistry, 2016, p. 110.
  • W. Bolton, "The Electrical Conductivity of Sodium Chloride", Book 4 - Electricity, Physics Experiments and Projects, 1968, p. 9-10.
  • W. Bolton, "Electrolytes", Book 4 - Electricity, Physics Experiments and Projects, 1968, p. 11-13.
  • Rudolf F. Graf, "Electrolysis of Water", Safe and Simple Electrical Experiments, p. 83.
  • Borislaw Bilash II, “Electrolytes and Nonelectrolytes“, A Demo A Day – A Year of Physical Science Demonstrations, p. 173.
University of Maryland Physics Department QOTW Question #191
University of Maryland Physics Department QOTW Answer #191