Electricity

Static electricity Accumulation of excess electric charges Some atoms hold their electrons more strongly than others! Law of Conservation of Charge “charges cannot be created or destroyed”

CONDUCTORS INSULATORS MOVE ELECTRONS EASILY DO NOT MOVE ELECTRONS EASILY METALS NONMETALS

Charging by “INDUCTION”…OR CONTACT! This is how balloons stick to walls… Why do you rub the balloon first on your head? *to “pull” electrons off your hair, and on to the balloon *the balloon now has more electrons than it should, causing it to become negative, while everything around it is positive. *and we all know what opposites do…don’t we? The same thing applies when you “shock” someone!

What about lightning? It’s the same thing… In this case the storm picks up electrons up off the ground. When the time is right it “discharges”, or releases the electrons back to the surface. This is also known as GROUNDING.

Electric current Current moves because of PRESSURE, in this case from high voltage to low voltage. The voltage difference is the “push” that causes charges to move (it is measured in volts, V). Electric current is the flow of electrons through a wire. It is measured in amperes (A). Resistance is anything that reduces the flow of electrons. It is measured in ohms (Ω). Why does a thin wire have high resistance?

Ohm’s law Current = volts/resistance or… I (amps) = V (volts) / R (Ω)

Series circuits The current has only one loop to flow ex) if one bulb is out, they are all out No current flows in an open circuit…the circuit in the picture is closed.

Parallel circuits The current has 2 or more paths to flow.

Household circuits Fuse boxes Circuit breakers

Electrical power The rate at which energy is converted to another form Power (watts) = current (amps) x voltage differential (volts) Power rating – explains the wattage for an appliance

Electrical energy Energy (kW hr) = power (kW) x time (hr)