1. What property of electric current allowed Edison’s first light bulb to light?

2. Electric Current
Electric current – The net movement of electric charges in a single direction through a wire or conductor. Voltage difference – The force that causes electric charges to flow; charges flow from high voltage to low voltage.

3. Circuit – A closed path that electric current follows Circuits include a power source (battery), wires, and some resistor (light bulb) and a voltage difference allows current to flow.

4. Batteries
Dry Cell
Chemical reactions occur in a moist paste causing the transfer of electrons
Ex. AA or D battery
Wet Cell
Contains two connected plates made of different metals in conducting solution.
Ex. Car battery

5. Resistance – The tendency for a material to oppose the flow of electrons, changing electrical energy into thermal and/or light energy. Ex. Light bulb, dial, switch, heating coil Making wires thinner, longer, or hotter increases resistance.

6. Current (I) = voltage difference (V)
All materials have some electrical resistance measured in ohms (Ω).
Ohm’s Law – current in a circuit equals voltage difference divided by the resistance.
Current (I) = voltage difference (V)
resistance (R )
Current measured in amps (A), voltage difference measured in volts (V), resistance measured in ohms (Ω)