Electricity on the MoveElectricity on the Move

Current ElectricityCurrent Electricity

Unlike static electricity, which does not Unlike static electricity, which does not move except when discharged, move except when discharged, current current electricityelectricity is a continuous flow of electric is a continuous flow of electric charge.charge.An example of this is a battery. When we An example of this is a battery. When we hook something up to a battery, the hook something up to a battery, the electrical current flows through a path electrical current flows through a path called a called a circuitcircuit..

Current Electricity:Current Electricity:

http://www.brainpop.com/science/energy/chttp://www.brainpop.com/science/energy/currentelectricity/preview.wemlurrentelectricity/preview.weml

Lighting a Light BulbLighting a Light Bulb

In order for a light bulb to light there must In order for a light bulb to light there must be a closed path to connect all of its be a closed path to connect all of its components.components.

This closed path is called a circuit.This closed path is called a circuit.

Circuit MeasurementsCircuit MeasurementsElectric Current Electric Current - - Flow of electrons Flow of electrons through a material. through a material. Measured as the amount of current that passes Measured as the amount of current that passes

a conducting wire every second.a conducting wire every second.Electrical Potential Electrical Potential – – Stored electric energy Stored electric energy

Circuit MeasurementsCircuit Measurements When given the opportunity, objects will When given the opportunity, objects will

move from higher potential energy to an move from higher potential energy to an area of lower potential energyarea of lower potential energy

Electrical potential is related to their Electrical potential is related to their electrical fields and not to height – electrical fields and not to height – as as electrons build up on one side they electrons build up on one side they “want” to flow to an area w/ less “want” to flow to an area w/ less potentialpotential

CircuitsCircuits

A path that allows an electric current to A path that allows an electric current to flowflow

We can use a We can use a circuitcircuit diagramdiagram to show the to show the path of the electric current. path of the electric current.

Copy symbols on page 353 and place by Copy symbols on page 353 and place by each name on the next two slideseach name on the next two slides

Understanding the SymbolsUnderstanding the Symbols

ConductingConducting wirewire allows electricity to flow allows electricity to flow easily easily

The The cellcell is an energy source. is an energy source.

A A batterybattery is a combination of cells. is a combination of cells.

A A lamplamp is a source of light is a source of light

Understanding Symbols (con’t)Understanding Symbols (con’t)

A A switchswitch will allow you to turn the will allow you to turn the electricity on or off without moving any electricity on or off without moving any components of the circuit. components of the circuit.

A A resistor resistor is used to represent any one of is used to represent any one of the many components (the many components (loadsloads) that convert ) that convert electrical energy to other forms of energy. electrical energy to other forms of energy. This resists the movement of charge This resists the movement of charge through a circuitthrough a circuit

Moving ChargesMoving Charges

The symbol for current is The symbol for current is II and the symbol and the symbol for charge is for charge is Q, t Q, t is used to represent time.is used to represent time.

Current = Current = charge moving past a pointcharge moving past a pointtimetime

I = I = QQ tt

Charge (Q) is measured in Coulombs (C)Charge (Q) is measured in Coulombs (C)

Current (I) is measured in Amperes (A)Current (I) is measured in Amperes (A)

Time (t) is measured in seconds (s)Time (t) is measured in seconds (s)

Answer the following QuestionsAnswer the following Questions1.1. How is static and current electricity different?How is static and current electricity different?

2.2. Give a real life example of one way that you have used Give a real life example of one way that you have used static electricity and current electricity?static electricity and current electricity?

3.3. What is it called when current electricity flows through What is it called when current electricity flows through a path?a path?

4.4. If 320 C of charge pass a point in a conductor in 7 min, If 320 C of charge pass a point in a conductor in 7 min, what is the current through the point in the conductor? what is the current through the point in the conductor? (Don’t forget the units!)(Don’t forget the units!)

VoltageVoltageVoltageVoltage – causes current to flow through an electrical circuit– causes current to flow through an electrical circuitVoltVolt – unit of measure to measure this potential– unit of measure to measure this potentialA A Voltage Source Voltage Source ((batterybattery or or generatorgenerator) is required to ) is required to maintain the electrical potential in a circuit.maintain the electrical potential in a circuit.

Electrical CurrentElectrical CurrentWater flowing thru a pipe depends on more than the angle Water flowing thru a pipe depends on more than the angle of the pipe. It also depends on the length of the pipe, of the pipe. It also depends on the length of the pipe, diameter of the pipe and if the pipe is clogged or open.diameter of the pipe and if the pipe is clogged or open.Electrical Current Electrical Current is measured in is measured in AmperesAmperesAmount of Electrical Current ( amps) depends on more Amount of Electrical Current ( amps) depends on more than just Voltage, it depends on the Resistance found in than just Voltage, it depends on the Resistance found in the circuit.the circuit.

Electrical ResistanceElectrical Resistancethe the oppositionopposition to the flow of electricity – to the flow of electricity – measured in measured in OhmsOhms – symbol is the – symbol is the Greek letter Omega Greek letter Omega --Water flowing thru a pipe depends on more than the angle Water flowing thru a pipe depends on more than the angle of the pipe. It also depends on the length of the pipe, of the pipe. It also depends on the length of the pipe, diameter of the pipe and if the pipe is clogged or open.diameter of the pipe and if the pipe is clogged or open.Electricity will take the Electricity will take the path of least resistancepath of least resistanceThe The greater the resistance, the less current greater the resistance, the less current there is for a there is for a given voltage.given voltage.

a. a. Longer wires Longer wires have have greater resistance greater resistance than short wiresthan short wires b. b. Thin wires Thin wires have have more resistance more resistance than thick wirethan thick wire c. High conductors have less resistance than insulatorsc. High conductors have less resistance than insulators