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Q & A: electron hopping

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Most recent answer: 03/03/2010
Q:
Electrons can be made to move from one atom to another. When those electrons move between the atoms, a current of electricity is created. The electrons move from one atom to another in a path. One electron is ATTACHED and another electron is LOST. How is that electron LOST? "Thank you" -Talia¢¾
- Talia (age 13)
Spokane,Washington
A:
You've given a nice description of how electrons move in some materials, hopping from site to site. I guess you're asking how the electron gets enough energy to shake loose from the first site so it can move over to the next one. Typically the electrons are shaken loose by the random thermal jiggles present in everything with any temperature. In materials like the one you describe (with electron hopping), the electrical conductivity increases as they are heated up.

Electrons in metals move very differently. We've described that in other answers. It involves a spread-out electron wave. In most metals, the conductivity goes down as they get hotter, because the electron waves bounce off of the thermal juggle waves.

In many common semiconductors (like the ones used in computers) the electrons move around as waves but the number that are free to move can depend on how many get unstuck from binding sites. Depending on the details, their conductivity can either go up or down with temperature.

Mike W.


(published on 03/03/2010)

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