1. Chapter 7 Electricity

2. Charge comes from Parts of the Atom
Nucleus (middle)
Protons – positive
Neutrons – neutral
Outside
Electrons – negative
It is the electron that is free to flow & causes electricity

3. How charges interact
Opposite Charges Attract & Like Charges Repel

4. Neutral and charged objects
Any charged object - will have an attractive force on a neutral object.
Positively charged objects attract Neutral objects
Negatively charged objects also attract Neutral objects

5. Types of electricity Flows from high to low voltage
Static electricity is stationary or the build up of charge on the surface of an object
Current electricity is the flow of electrons through a conductor.
Flows from high to low voltage

6. Conductors & Insulators
Conductor: a material that allows electric current to pass
Metals are good conductors
Insulator: a material that doesn’t allow electric current to pass
Plastic, glass, wood, and rubber

7. Charging Objects Charging by Contact
Transfer charge by touching or rubbing
Leaves one object with a (+) charge and the other with (-) charge
Ex. Rubbing feet on carpet builds up charge.
Charging by Induction
Rearrangement of charge on a neutral object by a nearby charged object
Ex. Touching something after charge was built up *SHOCK* or balloon sticking to a wall

8. Batteries: Devices that convert chemical energy to electricity
Batteries: Devices that convert chemical energy to electricity. They provide a voltage source
dry cell contains a moist chemical paste surrounding a carbon rod. The rod is suspended in the middle of the cell.
Ex. AA, AAA, C, etc

9. wet cell contains two connected metal plates in a conducting solution.
Ex. Most car batteries

13. 7.2 Electric circuits: contain a power source, wires, and devices that use the electrical energy.
Series circuit: provides a single pathway for current to flow. 1 loop
If the circuit breaks, all devices on the circuit will fail.
Ex. Cheap Christmas Lights

14. Parallel circuit: has multiple pathways for the current to flow
Parallel circuit: has multiple pathways for the current to flow. (Multiple loops)
If the circuit is broken the current passes through other pathways and other devices will continue to work.
Ex. Homes, cars

15. Voltage Difference (V)
Voltage Difference, or just voltage, (V)—the force that causes electric charges to flow
supplied by a battery or other power source.
Unit: Volts
Named in honor of Alessandro Volta

16. Electric Current (I)
Electric Current (I): the rate or the flow of electrons through a circuit
Symbol I comes from the French phrase intensité de courant, or in English current intensity
Unit: Amperes (amp)

17. Resistance (R) Unit: ohms (Ω—Greek letter Omega)
Resistance (R): opposes the flow of electrons, causing the electrical energy to be reduced
Unit: ohms (Ω—Greek letter Omega)
A resistor can be a light bulb or other device connected to a circuit

18. Voltage Difference = Current • Resistance V = I • R (volts) (amp) (Ω)
Ohm’s Law
Voltage Difference = Current • Resistance
V = I • R
(volts) (amp) (Ω)
German physicist Georg Simon Ohm ( ).