Lesson 2: What Makes a Circuit? Unit 1 Lesson 2: What Makes a Circuit?

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

Comprehension: Series Circuit

Vocabulary: Series Circuit Electric current – a flow of electric charges Electric circuit – a continuous pathway that can carry an electric current Series circuit – an electric circuit with only one path for current

Electric Current Electric current – a steady flow of electric charges Current electricity is used to power most electrical things It is easier to control than static electricity

Electric Current Electric currents can only move along paths It is not random It moves continuously, as long as there is a path to follow

Electric Circuit Electric circuit – a continuous pathway that can carry an electric current Pathways can be open or closed Closed pathways provide usable energy

Electric Circuit Circuits need a source to provide the movement of the electrical charges A battery is an example Two kinds of circuits: series and parallel

Series Circuit Series Circuit – an electric circuit with only one path for current to flow through An electric current must go all the way around for anything to work

Series Circuit: Travel of the electrical current First the current leaves the power source Then it travels through the wire It passes through each attached device Finally it ends up back in the power source This pattern repeats as long as the pathway is closed

Series Circuit + + + Battery + - Shows a series circuit in action - After a click, shows what happens when the series gets broken Battery +

Series Circuit Is mostly used for simple devices Flashlights, small lighted signs, bicycle flashers If one part of a series does not work, the whole thing will not work Everything attached to a series circuit is on when one thing is on

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

Series Circuit Buddy share: Would it be a good idea to use a series circuit in a house? Why or why not?

Comprehension Closure What is a series circuit?

Exploration: Series Circuit

Group Exploration: Making a Series Circuit Your group will go to two different stations You have a creation station as well as a writing station You will have 10 minutes at each station You will only rotate when the teacher tells you to

Exploration Closure: Series Circuit Draw a picture of a series circuit. Label the different pieces in your picture.

Comprehension: Parallel Circuit

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

Vocabulary: Parallel Circuit Parallel circuit – an electric circuit with two or more paths for current Resistance – how much a material opposes, or resists, the flow of electric current Short circuit – a flaw in a circuit that allows a large current to flow through where it isn’t wanted

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

Parallel Circuit Parallel circuit – an electric circuit with two or more paths for current If one path is blocked, the charges can use another path to continue moving It gives the electrical charges options for movement

Parallel Circuit You can put many different devices on a parallel circuit The current is split between pathways The current can go around an object not working Houses and buildings are wired with parallel circuits Adding another device does not change the capabilities of other devices

Parallel Circuit + + + + + Battery + - Shows a parallel circuit in action - After a click, shows what happens when the parallel gets interrupted Battery +

Resistance Resistance – how much a material opposes, or resists, the flow of electrical current The greater the resistance, the less current can pass through Smaller wire has greater resistance than thicker wire

Resistance Which wire would be better to use? Why?

Resistance = Light In a light bulb the light is actually the resistance of the electrical current The filaments (thin wires) in the bulb has high resistance First the filament gets hot, then it glows

Resistance = Light

Short Circuit Short circuit – a flaw in a circuit that allows a large current to flow through where it isn’t wanted A short circuit prevents the rest of a circuit from working

Short Circuit A safety device is a fuse A fuse has something that melts if it gets too hot and breaks the circuit This keeps damage from happening

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

Comprehension Closure: Parallel Circuits What is the difference between a series circuit and a parallel circuit?

Exploration: Parallel Circuit

Group Exploration: Making a Parallel Circuit Your group will go to two different stations You have a creation station as well as a writing station You will have 10 minutes at each station You will only rotate when the teacher tells you to

Exploration Closure: Parallel Circuits Draw a picture of a parallel circuit. Label the different pieces in your picture.