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Name: Flossie
Status: student
Age: 15
Location: N/A
Country: N/A
Date: 3/7/2003


Question:
What makes a metal more/less conductive than a different metal? How does this affect its resistance?


Replies:
Flossie,

A metal is a material that hold's one of its electrons very loosely. Very little energy is needed to break the electron free. Actually, just the little bit of heat energy present at room temperature will knock the electron loose. In most cases, these loose electrons in the metal just bounce around. Sometimes they rejoin with atoms for a while, only to be let loose again later on. Conductivity is how easily these electrons move through the metal. Atoms that grab loose electrons reduce conductivity. Large atoms or atoms sitting close together also decrease conductivity: the electrons have a greater chance of crashing into something.

Resistance is due to both conductivity and shape of the object. A more conductive material passes electrons more easily: less resistance to electron flow. A narrow object requires the electrons to be more tightly packed together as they flow. This results in more collisions: greater resistance. A longer object also increases resistance. Each electron crashes into more atoms passing through a longer object.

Dr. Ken Mellendorf
Physics Instructor
Illinois Central College


Flossie,

Electrical conductivity in metals is related to the ease with which electrons can flow through them. Not all metals offer the same opposition to electron flow. By the way, the words, "conductivity" and "resistance" are two (inverse) ways of referring to the same thing. Metals that have high conductivity are of low resistance. Those showing high resistance, are those of low conductivity.

Regards,
Richard L. Hoffman



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