2 Charge and ForceAll matter is made of atoms that contain ______________________, and protonsRecall that protons and electrons in atoms have electric chargeElectrons have a negative chargeProtons have a positive chargeWhen an object has an equal number of protons and electrons, the object has no charge
3 Types of electric charge Protons w/ ___________ “stuck” in the nucleus____________w/ ‘-’ charge freely moving around the nucleus in orbits
4 Neutrons have _____________ Neutrons have no effect on the chargeCharges in objects can produce a force between the objectsObjects are forced together or attracted when their charges are different“Opposite charges attract”Same electric charges they push apart“Like charges repel”
5 Electric ChargeAn electrical property of matter that creates a __________________objects. Depends on the imbalance of protons and electrons. i.e. net electric charge Measured in________________, C
6 Every charge has an electric field that surrounds it Every charge has an electric field that surrounds it. Electric fields exert force that causes other electric ____________________________. Any charge placed in that field will be pushed or pulled by that field.
7 Electric FieldsExert a force through ___________in all directions from the ________________When a charged particle enters the force field of another particle it is either_________________The diagram represents stronger force as the lines get closer & closer together
8 Electric ForceAttraction or repulsion between objects due to charge _______________________________
9 ____________of Charge Charge ________________________but it can be ______________ from object to object. Contact Transferring charge by__________________. Induction The rearrangement of electrons on a neutral object_______________________________
10 Static Electricity Static means ________________ Static electricity is electricity at rest_____________ can cause itObjects rub together and electrons move from one object another.
11 Static Charge Latin word “Stasis” which means “Stays” Objects are typically “Neutral” w/ the same # of protons and electronsThey can become “charged” by ________________electrons –NOT PROTONS! – They stay in the nucleus!The ________________of these charges is “Static Electricity”In Static Electricity the charges build up and STAY;they don’t flow as they do in electric currents
12 Transferring Static Charge Friction –____________________i.e. get shocked after walking on the carpetConduction –________________________contact w/ another object – hair standing on end w/ Van de Graff machineInduction – the force field of a highly negatively charged object _________________away from nearby objects causing them to become + charged, they then are attracted to each other. i.e. statically charged balloon attracts small pieces of torn up paper
13 Conductors Allow the _____________of electricity _____________ electrons that are free to move from atom to atommetals like aluminum, gold, copper and silver
14 Insulators Insulators –_________________of electrons hold more tightly to their ______________:plastic, rubber, glass
15 Interactions between charges same as in magnetismUnlike magnetism were on a magnet there is always a + on one end and a – on the other end of the magnetelectrical charges can exist aloneLike charges _________________ charges attract
16 Static discharge Eventually static electric charge will move. ________________may move into moisture in the airOr quickly in a ________.
17 Electric Current Electrons in motion. Current: The _____________that pass a specific point in a circuit in one secondVoltage: how ___________are being pushed.Circuit: electric current flows through a closed, __________________path.
18 Generating Electric Current Electrochemical cell: (battery) changes _______________________. Two types wet cell and dry cell.Thermocouples: a tool that uses differences in _____________________electric currents.Generator- next chapter but make alternating current
19 Types of currentDirect current: electrons that flow in the ______________________ in a wire. (DC)From batteriesAlternating current: electrons that flow in ___________________in a wire. (AC)From GenratorsUsed in your homeTransformers change AC to DC
20 Circuits For current to flow there must be a complete loop Electric circuit: ________________path through which electrons travel.Electrons flow from negative to positive terminalWork is done if there is a resistance in the wire.
21 Circuits Resistance is supplied by a resistor. A _________________is a device that uses electric energy to do work.A _________________from the resistor to the positive terminal completes the circuit.An open __________breaks the circuit.
22 Two Types of Circuits ______________: A circuit with only one path. All the resistors in a series circuit lie along a single path.The amount of current in a series circuit is the same at all parts of the circuit.Resistance in the circuit changes if resistors are added or taken away.
23 Series CircuitsSeries Circuits – provides __________for the electrons to follow1. A break in the circuit stops the flow of electricity to all other parts of the circuit2. With multiple light bulbs (more resistance) the current reduces & the dimmer the lights become3. Ammeters should be wired in series
24 ________________(2nd type of circuit) Parallel circuits: The electrons in a parallel circuit can travel through more than one path, each path is separate.If there’s a break in one path in the circuit, electrons can still flow through the other paths and maintain a complete circuit.
25 Parallel CircuitsParallel circuits – the different parts of the circuit are on __________ branchesA break (burn out light bulb) in the circuit doesn’t stop the flow to the remaining devicesMultiple light bulbs will remain the same brightness since the resistance is not decreasing as it does in a series circuit.Each pathway can be separately switched off w/out affecting the othersHousehold circuits – Wired in parallel, with a standard of 120 voltsVoltmeters are wired in parallel
26 Parallel Circuits The ___________________________ Water example again: added pipes coming from a large tank will allow more water to flow out that a single pipe.Therefore as resistance degreases, current increases; they are inversely proportional
27 Schematic Diagrams (Draw the symbols and diagrams into your notes) All circuits need at least the followingPower supply, wire, resistors, other items include switches, connectors, meters, etc.There is a set of standard symbols used to represent these items in a diagram of the circuit
28 Electric power and energy Power: The rate at which ________________ or provides energy The amount of electric power a device uses to do work is determined by its resistance.______________(P) power = (V) voltage x (I) current in the circuit.
29 Formula for energy________________(E) energy used = (P) power x (t) timeThe SI unit for energy is a joule.Kilowatt-hour meters measure the electricity used in your home.(kWh)
30 Circuit Measurements______________- Flow of electrons through a materialElectrical Potential –Similar to potential energy (lifting something higher against the force of gravity gives it greater potential_________, increasing its potential energy.)When given the opportunity, objects will move from higher potential energy to an area of lower potential energyElectrical potential is related to their electrical fields and not to height – as electrons build up on one side they “want” to flow to an____________________________
31 Voltage Voltage – causes current to flow through an electrical circuit _______– unit of measure to measure this potentialA Voltage Source (battery or generator) is required to maintain the electrical potential in a circuit.
32 Electrical CurrentWater flowing thru a pipe depends on more than the angle of the pipe. It also depends on the length of the pipe, diameter of the pipe and if the pipe is clogged or open.Electrical Current is ____________________Amount of Electrical Current ( amps) depends on more than just_______, it depends on the_______________ found in the circuit.
33 Electrical Resistance the opposition to the flow of electricity –__________________– symbol is the Greek letter Omega -Water flowing thru a pipe depends on more than the angle of the pipe. It also depends on the length of the pipe, diameter of the pipe and if the pipe is clogged or open.Electricity will take the path of least resistanceThe greater the resistance, the less current there is for a given voltage.A_____________have greater resistance than short wiresb. Thin wires have more________________ than thick wirec. _______________have less resistance than insulators
34 Ohm’s LawThe relationship among current, voltage, and resistance.Ohm’s law states that the _______in a circuit is equal to the ______ divided by the ________________I = V RVIR
35 Electric safetyMany appliances are equipped with a _________________on the plug.The ground wire prevents ____________. The rounded third prong of a three-way electric plug is attached to the ground wire.It constantly moves static electricity from the appliance to the ground.
36 Broken wires or water can cause electric appliances to short-circuit. A _____________occurs when electricity takes a short path and bypasses the resistors in the circuit.Because of this the resistance of the circuit is less and the circuit wire increases.The increased current can produce enough heat to melt wires and start a ______, or cause serious___________________.
37 Circuit protectors________________protect against overloaded circuits.A number on the fuse indicates the max. current that will flow through it.Circuit breakers are often used in place of fuses. A circuit breaker is_______________ automatically when electric current in a circuit reaches its max.