Write this in your notebook. 5.3 Dynamic Electricity Write this in your notebook. There are 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) causing an electric current to flow.

Write this in your notebook. Electric Current Write this in your notebook. Electric current is the orderly flow of electrons through a conductor. (Fig. 5.19) 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

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

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

Pure water is NOT a good conductor Nichrome is a POOR conductor used in resistors, toasters, radiators…

Conductance of a wire depends on: Length Diameter Temp Material Copper is excellent Nichrome is NOT SHORT Good conductance FAT COLD

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

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

Write this in your notebook. Important Points: Copper is an excellent conductor Wires that are: SHORT FAT COLD Nichrome is an excellent insulator & a terrible conductor! Write this in your notebook. have a high conductance