1. Electrical Current

2. Detecting electrical charge Electroscope: an instrument to detect electrical charge

3. Electrical Current Electrical current: the movement of electric charges in a single direction Measured in amperes One ampere = 6250 million electrons moving past a single point every second

4. Voltage difference Voltage difference: electrical charge flows from a higher voltage to a lower voltage which keeps the electrical flow going Measured in volts

5. Electrical Circuit Electrical circuit: a closed path that electric current flows through Batteries: keep the voltage difference maintained in the circuit in order to keep the current flowing

7. Dry-Cell Batteries Dry-cell batteries: 2 electrodes surrounded by an electrolyte Electrode: an electric semi-conductor with a carbon rod that is positive and a zinc part that is negative Electrolyte: a moist paste containing several chemicals Use more batteries to create a higher voltage Examples: cell phone battery, Duracell batteries, iPod batteries

8. Dry-cell Batteries

9. Wet-cell batteries Wet-cell batteries: contains 2 connected metal plates in a conducting solution. The solution transfers electrons which transfers electric charge Examples: car, truck, boat batteries

10. Lead-acid Batteries Lead-acid batteries: wet-cell batteries made up of lead plates and sulfuric acid solution Examples: car batteries

11. Resistance Resistance: the tendency for a material to oppose the flow of electrons which changes electrical energy into thermal energy or light energy Insulators = more resistance Conductors = less resistance Measured in ohms (Ω) Copper: used in household wiring because it produces less heat

12. Resistance Factors that increase resistance of a wire: Temperature: as the temperature of the wire increases, the resistance increases Length: as the length of the wire increases, the resistance increases Diameter: as the diameter of the wire increases, the resistance increases

13. Ohm’s Law Ohm’s Law: the current in a circuit equals the voltage difference divided by the resistance I = current R = resistance V = volts I = V/R R = V/I V = IR

14. Electrical energy and circuits Circuits include: 1. A source of voltage difference (battery or outlet) 2. A device that uses electrical energy (light bulb) 3. Conductors that connect the device to the voltage difference (wires)

15. Circuits in Series Circuits in a Series: the current only has one circuit loop to flow through

16. Open Circuits Open circuit: the parts in the series are wired one after the other, if one part is disconnected, no current flows through the circuit Example: Christmas lights

17. Parallel Circuit Parallel circuit: contains 2 or more branches for current to flow though The current can flow through both or one of the branches at a time Example: household circuits

18. Fuses and circuit breakers Fuses: If the current becomes too high, a small piece of metal melts and causes a break in the circuit, stopping the flow of current Circuit breaker: a device that prevents a circuit from overheating and causing a fire

19. Electrical Power Electrical Power: the rate at which electrical energy is converted to another form of energy Equation: P = I x V I = P/V V = P/I Measured in Kilowatts because watts are small units of power

20. Electrical Energy Electrical Energy: the power company charges for the electrical energy used in your home and is measured in kilowatt hours (kWh) Electrical energy equation: E = P x t P = E/t t = E/P