Electricity 2 types of electricity Static electricity: when electrical charges are at rest (as we have already covered). Dynamic electricity: when electrical charges are in motion (in a wire loop) causing an electric current to flow.

Electric Current Electric current is the orderly flow of electrons (Fig. 5.19) through a conductor. Electron flow: the direction the electrons actually move (- to +) Conventional current: the direction positive particles would flow if they could move (+ to -). BUT THEY DON’T MOVE! Only the electrons move.

Conductors & Insulators

Conductors: Substance that allows electric current to pass. Most metals. Ex. - Metal wires (ex. Aluminum or copper) or graphite rods

Insulators: Substance that does NOT allow electric current to pass. Most non-metals. Ex. - Plastic, Wood, Paper, Rubber, Glass, Ceramics

Semi-Conductor Substance that partially allow electric current to pass are semi-conductors. Metal alloys are semi-conductors. Metal alloys are a mixture of metals or metals and non-metal products. Ex – Steel (iron and carbon), electrum (silver and copper), brass (copper and zinc), stainless steel (steel, chromium and nickel), white gold (gold, nickel, and palladium), and pewter (lead and copper)

Wood, Rubber, Vinyl, Glass, Plastics are not a good conductor Water, is a good conductor (sort of) Copper, Aluminum, Zinc, Iron, Lead are GOOD conductors Steel, Brass and Pewter are GOOD semi-conductor

SHORT Thick COLD Conductance of a wire depends on: Length Diameter Temp Material Copper is excellent Metals better than non-metals SHORT Thick COLD

Ex #1 Ex #2 Which is a better conductor? Plastic Copper Wood Iron Which metal wire has the best conductance?

Ex #3 Which wire is the best conductor? SHORT THICK COLD Wood 55oC Copper 25oC SHORT THICK COLD Copper 25oC Copper 55oC Aluminum 25oC Copper 5oC

have a high level of conductance Key Points to Remember Copper and Aluminum are excellent conductors Wires that are: SHORT THICK COLD have a high level of conductance

Key Points to Remember Conductors – creates an electrical current Insulators – prevent an electrical current from happening Semi-Conductors – partially create an electrical current