The origin, motion, and energy of electrons in circuits; The role of batteries as energy sources and resistors as energy dissipaters in circuits; Conceptual.

•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?

Let’s see what else you remember!

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

protonelectron

neutron

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

protonelectron

neutron

_________ means to push away.

_________ means to pull together.

charge

attract

repel

charge

attract

repel

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

positive negativ

e

neutral

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

positive negativ

e

neutral

In Chemistry, you already learned about the interaction of charges.

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 start with some vocab…

Electricity

Circuit

Current

Let’s start with some vocab…Electricity- a form of energy

resulting from movement of charged particles.

Circuit- a loop that electrons can flow through- can be open or closed

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

open circuit

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

Open circuit

Closed 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.

Conductor

Insulator

Continue

Insulator: a substance through which electricity cannot flow readily

Examples…

wood plasticrubber

sulfur glass

Conductor: a material through which electrons can move easily

Examples…

brass aluminumcopper

graphite water

Which of these items are conductors?

Which of these items are insulators?

What’s the Best Pathway for Electrons?http://www.youtube.com/watch?v=

VnnpLaKsqGU

There are two main types of circuits:

Parallel

Seriesand

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?

parallel

series

parallel

series

parallel

series

parallel

series

Holiday lights

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

Challenge!

Can you…1. Make a series circuit with two lightbulbs?2. Make a parallel circuit with two lightbulbs? (so that

one lightbulb can be OFF while the other is ON)3. Make a series circuit with a switch using the

materials in the bag? Then a parallel circuit with a switch?

4. Determine which of the materials in the bag are electrical insulators and conductors?

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:http://www.youtube.com/watch?v=Aq31mjWYdJ8

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

• A chemical reaction inside a battery causes a separation of charges

• This separation of charges causes a build

up of potential energy.

• Electrons flow from high PE to low PE.

• Just like gravitational potential energy… (recall video)

Review from yesterday…

The Circuit

Potential Difference (voltage)

•Voltage is the measure of potential energy supplied to each coulomb of charge•Units- volts (V)•Measure with a multimeter• Is dependent on the energy source NOT the circuit! • the more volts a source has, the more

potential energy it has.

After the reading “what is voltage?”

•Voltage is like water pressure

• a “force” that causes the current to

flow

Current•The rate (“speed”) at which electrons flow•Unit- ampere (A)•(aka “amps”)•Measure with a multimeter

•An amp is one coulomb of charge per second

Resistance

•Opposes the rate of flow of charge

•Unit- Ohms ()

Resistors- anything that creates resistance in a circuit. (slows down current)•Can you think of any examples?

Video: http://www.youtube.com/watch?v=Gc1wVdbVI0E(only show first 3 minutes)

Current vs Voltage

http://www.youtube.com/watch?v=WvcwCttJjtI

How are resistance and current related?

- Lab and worksheet

•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