CHAPTER 6, SECTION 3

Series and Parallel Circuits: Lighten Up

HW: 6.3 PTG #1-9

• LO – Compare series and parallel

circuits and learn the language of electricity.

• SC– Compare series and parallel

circuits– Recognize generator output

limit– Modify the Electron-Shuffle

model of electricity

• Do Now:– Copy LO and SC on new

left side page– WDYS/WDYT pg. 614

• Agenda:– Do Now– Investigate Part A

INVESTIGATE PART A• Electron Shuffle– 3 bulbs in parallel– Coulombs go to

• Light Bulb 1 if your bday is in Jan, Feb, Mar, Apr• Light Bulb 2 if your bday is in May, June, July, August• Light Bulb 3 if your bday is in Sept, Oct, Nov, Dec

• 1-volt battery=1 Joule per Coulomb– Battery: “The battery Voltage is 1 Volt, which equals one joule

of energy for each coulomb”– Coulomb: “One coulomb of energy receiving one joule of

energy”– Light Bulb: “I just received 1 Joule of energy from that

coulomb”

STUDENTS ANSWER...

• Pg. 615– #4a, b

INVESTIGATE PART A

• Electron Shuffle– 3 Volt battery– 1 Amp current

INVESTIGATE PART A

• Electron Shuffle– 1 Volt battery– 2 Amp current

STUDENTS ANSWER…

• Pg. 616– #7 a-e

HW: 6.3 PTG #1-9

• LO – Compare series and parallel

circuits and learn the language of electricity.

• SC– Compare series and parallel

circuits– Recognize generator output

limit– Modify the Electron-Shuffle

model of electricity

• Do Now:– What happened to the

brightness of the bulbs in a parallel circuit when compared to the bulbs in series circuit?

• Agenda:– Do Now– Investigate Part B

INVESTIGATE PART B

• #1-2 complete in groups, discussion• #3-4 complete in groups, show teacher• #5-6 complete in groups, show teacher,

discussion

PHYSICS TALK

• Series Circuit • Total voltage of the battery is divided equally between all bulbs in the circuit.

• Coulombs of charge must go through each bulb and drop off joules of energy.

• If one bulb is removed, the circuit is open and ALL the bulbs will go out.

• 1 volt battery, each bulb will receive 1/3

• Bulbs will appear dimmer

PHYSICS TALK

• Parallel Circuit • Total voltage provided to each bulb is equal to the voltage of the battery.

• Each bulb has a complete circuit from the battery to the bulb and back to the battery

• If one bulb is removed, others will remain lit

• Bulbs will be equally bright.• Battery will run out more

quickly

PHYSICS TALK

• Series example:• 6 volt battery• How many joules will

each bulb get?

• Parallel Example• 6 volt battery• How many joules will

each bulb get?

PHYSICS TALK

• What about the current in a parallel circuit?

• Current (coulombs/sec) is divided in a parallel circuit

• Example: If a parallel circuit has a 3 amp current, each bulb gets one amp of current

• How much current would each bulb get if it was a 9 amp circuit?

• Put it all together! • 9 Volt battery with a 3 amp current– Each bulb receives ____

joules of energy– Each bulb receives ____

amps of current

• Put it all together! • 9 Volt battery with a 3 amp current– Each bulb receives __9__

joules of energy– Each bulb receives __1__

amps of current

– One coulomb will pass each resistor (bulb) every second and drop 6 volts there.

PHYSICS TALK

• What is a resistor?

• What is voltage drop?

• A conductor that controls the current in a circuit.

• How many joules the coulomb drops off at each resistor

THE LANGUAGE OF ELECTRICITY

• 2 kinds of electric charges– Positive (protons)– Negative (electrons)

• Like charges (++ or - -) will repel

• Protons and electrons have opposite but equal charges– Protons (1+)– Electrons (1-)

THE LANGUAGE OF ELECTRICITY

• Electrons move in circuits and carry the electrical current delivering energy to the bulb

• Protons do not flow because they are locked within atoms

• Standard “package” of electric charge is called a Coulomb (C)=6.25 x 1018 electrons– Approximately the charge of a bolt of lightning!

THE LANGUAGE OF ELECTRICITY

• Standard rate of flow through a circuit is an ampere (A). – # coulombs that pass through a point in one

second

THE LANGUAGE OF ELECTRICITY• Resistance is the opposition to the flow of electric

charge– Resistors are objects that oppose flow of electric charge

(light bulb)– Example: High resistance-Tungsten filaments in light bulbs

glow as they “rob” energy from passing electrons, causes the tungsten to get hot and glow=LIGHT!

– Example: Low resistance-copper wire, electrons transfer little energy so we use copper to conduct electricity in circuits

– Measured in Ohms (Ω)– Was the steel wool high or low resistance? Why?

THE LANGUAGE OF ELECTRICITY

• Batteries or generators provide energy to the electrons (coulombs)

• Energy given to each coulomb is measured in Volts (V)

HOW DO WE DRAW CIRCUITS?

ESSENTIAL QUESTIONS PG. 620

• What does it mean?• How do you know?• Why should you care?

• LO and SC reflection