# Electricity - PowerPoint PPT Presentation

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Electricity. The origin, motion, and energy of electrons in circuits; The role of batteries as energy sources and resistors as energy dissipaters in circuits; Conceptual understanding of potential difference (i.e., voltage); Current and resistance and the relationship between them.

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Electricity

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#### Presentation Transcript

Electricity

• The origin, motion, and energy of electrons in circuits;

• The role of batteries as energy sources and resistors as energy dissipaters in circuits;

• Conceptual understanding of potential difference (i.e., voltage);

• Current and resistance and the relationship between them.

What Gives Matter a Charge?

• Objects with opposite charges (one negative, one positive) will attract each other.

• Objects with like charges (both negative or both positive) will repel each other.

Let’s see what else you remember!

A particle with a positive charge is called a/an _______________.

proton

neutron

electron

A particle with a negative charge is called a/an _______________.

proton

neutron

electron

_________ means to push away.

_________ means to pull together.

charge

charge

attract

attract

repel

repel

If an electrically-neutral object GAINS electrons, what charge does it now have?

positive

neutral

negative

If an electrically-neutral object LOSES electrons, what charge does it now have?

positive

neutral

negative

Electricity

Circuit

Current

Electricity- a form of energy resulting from charged particles.

Circuit- a closed loop that electrons can flow through

Current-a measure of the flow of electrons (how many electrons pass a point per second)

(measured in Amps)

What is the difference between open and closed circuits?

Click on a term to reveal its definition.

circuit

opencircuit

closed circuit

Proceed to quiz

Circuit:

A closed-loop path of conduction through which an electric current flows

Open circuit:

An incomplete path that will not permit an electric current to flow

Closed circuit:

A complete path for electric current

Quiz:

What type of circuit is shown in each of the following examples?

Open circuit

Closed circuit

Open circuit

Closed circuit

Closed circuit

Open circuit

Open circuit

Closed circuit

Open circuit

Closed circuit

How Do You Make Electricity Do What You Want?

Click on a term to reveal its definition and examples.

Insulator

Conductor

Continue

Insulator: a substance through which electricity cannot flow readily

Examples…

woodplasticrubber

sulfur glass

Conductor: a material through which electrons can move easily

Examples…

brassaluminumcopper

graphite water

Which of these items are conductors?

Which of these items are insulators?

What’s the Best Pathway for Electrons?

There are two main types of circuits:

Parallel

Series

and

Parallel circuits are circuits with more than one pathway through which electrons can flow.

Series circuits are circuits with only one pathway through which electrons can flow.

What type of circuits are shown in the following examples?

series

parallel

parallel

series

parallel

series

Holiday lights

parallel

series

Types of energy sources:

• Battery:

• Has two TERMINALS:

• One positively charged & one negatively charged

• Chemical reaction occurs in the battery that separates the charges to the positive and negative sides

Electric Potential Energy

• This separation of charges (from the chemical reaction) causes a build up of potential energy.

• Electrons flow from an area of high PE to low PE.

• Just like gravitational potential energy… video

Battery cont

• When a circuit is created , electrons flow from the negative end to the positive end

• electrons are repulsed by the negative side and attracted to the positive side

Electrical Energy can be transferred

• This separation of charges (from the chemical reaction) causes a build up of potential energy.

• Electrons flow from an area of high PE to low PE.

• Just like gravitational potential energy… video

The Circuit

After the reading “what is voltage?”

• Voltage is like water pressure

• Voltage is like a “force” at which the current will flow

Potential Difference (voltage)

• Voltage is the measure of potential energy supplied to each coulomb of charge

• Units- volts (V)

• Is dependent on the energy source NOT the circuit!

• the more volts a source has, the more potential energy it has.

• The rate (“speed”) at which electrons flow

• Unit- ampere (A)

• (aka “amps”)

• An amp is one coulomb of charge per second

Current

• An amp is one coulomb of charge per second

• A coulomb is the unit for charge

• There are about 6.24x 1018 electrons in one coulomb

Resistance

• Opposes the rate of flow of charge

• Unit- Ohms ()

How are resistance and current related?

- Lab and worksheet