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Name: Nathan U.
Status: educator
Age: 50s
Location: N/A
Country: N/A
Date: 8/2/2004

I am reviewing some materials for the electricity unit in my physics classes. I have come across similar passages in different texts as follows: "A conductor in both the solid state and liquid state can carry a current to complete an electrical circuit. However, a solid conductor involves the movement of electrons through the atomic lattice, whereas a liquid conductor transports ionic charges through the solution." (Northwestern University Materials World Modules, 2002).

I am puzzled by this generalization of liquids. How does liquid mercury or sodium (nuclear reactor design) conduct electricity? I am not aware of the requirement of ions.

Nathan U.,

Whenever you have electrons leaving atoms to travel through the medium, you have positive ions left behind. With a solid, electrons (usually one per atom) move through the material and the ions left behind just stay put. Because the material is solid, the atoms cannot move. In a liquid, the atoms can move. Of course, they do not move nearly as fast as or in the same direction as the electrons. Still, they do move.

Dr. Ken Mellendorf
Physics Instructor
Illinois Central College

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