Conductivity Notes

Plasma - 4th State of Matter

Most people view electricity
in the following way ...

What's wrong with

this animation?

Batteries don't supply the electrons
that flow through the wire.

Instead, they create an electric field that 'push on' the electrons that are already in the wire.

Alessandro Volta's electric battery prototype

(18 century)

Electric Current

- stream of electrically charged particles passing through a given area (movement of electrons in a wire

A) Conductivity of Solids

1) Metals - contain many free electrons (good conductors)

2) Glass, fused quartz, rubber - good insulator

Few free electrons

Insulators have a High Resistivity (Structural resistance to electrons flow)

3) Semiconductor - a material with a resistance between conductor and an insulator

B) Conductivity of Liquids

1) pure liquids don’t conduct

2) liquid with dissolved ions conduct

(electrolyte solution)

(ion movement transfers charge
not electrons)

C) Conductivity of Gases

Gases conduct when ionized (charged) when exposed to:

a) high energy radiation

b) OR electric field

c) OR with collision with high speed particles

Charge in a gas is transferred by ions and electrons

Plasma–very hot ionized gas

4th state of matter

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