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?

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 see what else you remember!

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

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

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

Let’s start with some vocab… Electricity Circuit Current

Let’s start with some vocab… 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 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… 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: ParallelSeries 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? parallel series

parallelseries

parallelseries

parallelseries 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

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.

Current The rate (“speed”) at which electrons flow Unit- ampere (A) (aka “amps”) An amp is one coulomb of charge per second

A coulomb is the unit for charge There are about 6.24x electrons in one coulomb

Resistance Opposes the rate of flow of charge Unit- Ohms (  )

How are resistance and current related? - Lab and worksheet