Unit 1Unit 1

Lesson 2: What Makes a Circuit?Lesson 2: What Makes a Circuit?

Objective: Series CircuitObjective: Series Circuit

By the end of this lesson you should be By the end of this lesson you should be able to define a series circuit.able to define a series circuit.

Comprehension: Series Circuit

Vocabulary: Series CircuitVocabulary: Series Circuit

Electric current – a flow of electric Electric current – a flow of electric chargescharges

Electric circuit – a continuous pathway Electric circuit – a continuous pathway that can carry an electric currentthat can carry an electric current

Series circuit – an electric circuit with Series circuit – an electric circuit with only one path for currentonly one path for current

Electric Current Electric Current

Electric current – a steady flow of electric Electric current – a steady flow of electric chargescharges

Current electricity is used to power most Current electricity is used to power most electrical thingselectrical things

It is easier to control than static electricityIt is easier to control than static electricity

Electric CurrentElectric Current

Electric currents can only move along Electric currents can only move along pathspaths It is not randomIt is not random It moves continuously, as long as there is a It moves continuously, as long as there is a

path to followpath to follow

Electric CircuitElectric Circuit Electric circuit – a Electric circuit – a

continuous pathway that continuous pathway that can carry an electric can carry an electric currentcurrent

Pathways can be open or Pathways can be open or closedclosed

Closed pathways provide Closed pathways provide usable energyusable energy

Electric CircuitElectric Circuit

Circuits need a source to provide the Circuits need a source to provide the movement of the electrical chargesmovement of the electrical charges A battery is an exampleA battery is an example

Two kinds of circuits: series and parallelTwo kinds of circuits: series and parallel

Series CircuitSeries Circuit

Series Circuit – an electric circuit with Series Circuit – an electric circuit with only one path for current to flow throughonly one path for current to flow through

An electric current must go all the way An electric current must go all the way around for anything to workaround for anything to work

Series Circuit: Travel of Series Circuit: Travel of the electrical currentthe electrical current

First the current leaves the power sourceFirst the current leaves the power source Then it travels through the wireThen it travels through the wire It passes through each attached deviceIt passes through each attached device Finally it ends up back in the power Finally it ends up back in the power

sourcesource This pattern repeats as long as the This pattern repeats as long as the

pathway is closedpathway is closed

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Series Circuit Series Circuit

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Series CircuitSeries Circuit

Is mostly used for simple devicesIs mostly used for simple devices Flashlights, small lighted signs, bicycle flashersFlashlights, small lighted signs, bicycle flashers

If one part of a series does not work, the If one part of a series does not work, the whole thing will not workwhole thing will not work

Everything attached to a series circuit is on Everything attached to a series circuit is on when one thing is onwhen one thing is on

Series CircuitSeries Circuit

The more devices attached to a series The more devices attached to a series circuit, the less effective each device iscircuit, the less effective each device is Which circuit will have the brightest lights? Which circuit will have the brightest lights?

Why?Why?

Series CircuitSeries Circuit Buddy share:Buddy share: Would it be a good idea to Would it be a good idea to

use a series circuit in a house? Why or use a series circuit in a house? Why or why not?why not?

Comprehension Closure Comprehension Closure

What is a series circuit?What is a series circuit?

Exploration: Series Circuit

Group Exploration: Group Exploration: Making a Series CircuitMaking a Series Circuit Your group will go to two different stationsYour group will go to two different stations

You have a creation station as well as a writing stationYou have a creation station as well as a writing station

You will have 10 minutes at each stationYou will have 10 minutes at each station

You will only rotate when the teacher tells you toYou will only rotate when the teacher tells you to

Exploration Closure: Exploration Closure: Series CircuitSeries Circuit

Draw a picture of a series circuit. Label the Draw a picture of a series circuit. Label the different pieces in your picture.different pieces in your picture.

Comprehension: Parallel Circuit

Objective: Parallel CircuitObjective: Parallel Circuit

By the end of this lesson you should be By the end of this lesson you should be able to define a parallel circuit and tell the able to define a parallel circuit and tell the difference between a series and a difference between a series and a parallel circuit.parallel circuit.

Vocabulary: Parallel Vocabulary: Parallel CircuitCircuit

Parallel circuit – an electric circuit with Parallel circuit – an electric circuit with two or more paths for currenttwo or more paths for current

Resistance – how much a material Resistance – how much a material opposes, or resists, the flow of electric opposes, or resists, the flow of electric currentcurrent

Short circuit – a flaw in a circuit that Short circuit – a flaw in a circuit that allows a large current to flow through allows a large current to flow through where it isn’t wantedwhere it isn’t wanted

Check in…Check in…

Remember that a series circuit is a circuit Remember that a series circuit is a circuit where there is only one path for the where there is only one path for the energy to flowenergy to flow

Parallel CircuitParallel Circuit Parallel circuit – an Parallel circuit – an

electric circuit with two electric circuit with two or more paths for currentor more paths for current

If one path is blocked, If one path is blocked, the charges can use the charges can use another path to continue another path to continue movingmoving

It gives the electrical It gives the electrical charges options for charges options for movement movement

Parallel CircuitParallel Circuit

You can put many different devices on a You can put many different devices on a parallel circuitparallel circuit The current is split between pathwaysThe current is split between pathways The current can go around an object not The current can go around an object not

workingworking

Houses and buildings are wired with Houses and buildings are wired with parallel circuitsparallel circuits

Adding another device does not change the Adding another device does not change the capabilities of other devicescapabilities of other devices

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Parallel Circuit Parallel Circuit

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Resistance Resistance

Resistance – how much a material Resistance – how much a material opposes, or resists, the flow of electrical opposes, or resists, the flow of electrical currentcurrent

The greater the resistance, the less The greater the resistance, the less current can pass throughcurrent can pass through

Smaller wire has greater resistance than Smaller wire has greater resistance than thicker wirethicker wire

ResistanceResistance

Which wire would be better to use? Which wire would be better to use? Why?Why?

Resistance = LightResistance = Light In a light bulb the light In a light bulb the light

is actually the is actually the resistance of the resistance of the electrical currentelectrical current

The filaments (thin The filaments (thin wires) in the bulb has wires) in the bulb has high resistancehigh resistance

First the filament gets First the filament gets hot, then it glowshot, then it glows

Resistance = LightResistance = Light

Short CircuitShort Circuit

Short circuit – a flaw in Short circuit – a flaw in a circuit that allows a a circuit that allows a large current to flow large current to flow through where it isn’t through where it isn’t wantedwanted

A short circuit prevents A short circuit prevents the rest of a circuit the rest of a circuit from workingfrom working

Short CircuitShort Circuit

A safety device is a fuseA safety device is a fuse A fuse has something that melts if it gets A fuse has something that melts if it gets

too hot and breaks the circuittoo hot and breaks the circuit This keeps damage from happeningThis keeps damage from happening

FuseFuse

Has anyone ever plugged something in Has anyone ever plugged something in and it doesn’t work? Why might that be?and it doesn’t work? Why might that be?

Comprehension Closure: Comprehension Closure: Parallel CircuitsParallel Circuits

What is the difference between a series What is the difference between a series circuit and a parallel circuit?circuit and a parallel circuit?

Exploration: Parallel Circuit

Group Exploration: Group Exploration: Making a Parallel CircuitMaking a Parallel Circuit Your group will go to two different stationsYour group will go to two different stations

You have a creation station as well as a writing stationYou have a creation station as well as a writing station

You will have 10 minutes at each stationYou will have 10 minutes at each station

You will only rotate when the teacher tells you toYou will only rotate when the teacher tells you to

Exploration Closure: Exploration Closure: Parallel CircuitsParallel Circuits

Draw a picture of a parallel circuit. Label Draw a picture of a parallel circuit. Label the different pieces in your picture.the different pieces in your picture.