Unit 4: Electricity for Everyone

Essential Questions

• What is electricity and how is it measured?• How do generators work?• How is energy converted from one form to

another?• What are parallel and series circuits? • What is a load limit, and how is it

calculated?• What does electricity cost?

Chapter Challenge

• For this unit’s chapter challenge, you will be using the scenario on page 444-445

• This is what your final exam will be in December

• A rubric will be given to you beforehand, so you know the criteria you will be assessed on

• You may prepare for the chapter challenge, but you can not bring any of your written work to the exam, only your textbook and rubric

Day 1: Generate (60 minutes)

• Learning Objectives• To understand how energy is transformed• Develop a personal model for electricity

Starter

• What are different ways that you use electricity in your daily life?

• Is there any “free” electricity available? Why pay for it if it is free?

• Time: 10 minutes

Activity 1

• Watch the following video and think of the following:• How would the light bulb not light?• What are the effects of changing the speed or

direction of cranking the generator?

• Time:

Activity 2

• You will be given a number which represents the group you are in

• You will research with your group and present what you find in a particular way

1. Powerpoint2. Poster3. Poem/Story/Comic strip

What to research?

• What is a generator?• How does it work?• What are the different types of generators?• How is energy transformed using a

generator?• Time: 40 minutes• Presentations – next class

Closing and Homework

• Physics to Go, pg. 449 #2, 3, 4, 6

Day 2: Lighten Up

• Learning Objectives:• Qualitatively describe current, resistance and

voltage• Define coulomb, ampere, volt• Compare series and parallel circuits• Recognize generator output load• Extend your personal model of electricity

Starter

• Lights were the first electric appliances for the home

• How do light bulbs work?• How does the electricity that makes the

light bulbs glow work?• Time: 15 minutes

Activity 1

• Present your information that you researched about generators

• Time: 15-30 minutes

Activity 2

• Draw 2 diagrams of a circuit, one in series and one in parallel. They should have • 3 light bulbs• Battery

• What are the pros and cons of each type of circuit?

• Time: 10 minutes

Activity 3

• Set up your circuits, one at a time• Measure the voltage using the voltmeter to

see if there are any differences in voltage in the two different circuits

• Check the voltage at various points in the circuit

• Write down your findings• Time: 30 minutes

Activity 4

• Discuss the following questions:• What is resistance, current, and voltage?• Where is there more current and voltage – in a

series circuit or parallel circuit?• Will electricity continue to flow if the circuit is

broken in a parallel circuit? A series circuit? Why or why not? Use a diagram to help explain.

• Time: 20 minutes

Closing and Homework• Read “For you to Read”, pg. 452• Physics to go, pg. 454 #1• What is resistance, current, and voltage?• Where is there more current and voltage – in a series circuit or

parallel circuit?• Will electricity continue to flow if the circuit is broken in a

parallel circuit? A series circuit? Why or why not? Use a diagram to help explain.

• Vocabulary list:• Volt• Ampere• Coulomb • Resistance• Current

Day 3: Ohm’s Law

• Learning Objectives• Calculate the resistance of an unknown

resistor given the potential drop and current• Construct a series circuit • Properly use a voltmeter and ammeter in a

series circuit• Graph the relationship between voltage and

current for a resistor that obeys Ohm’s La

Starter• What determines the brightness of a light

bulb?• How can a dimmer switch make the same

light bulb appear dim or bright?• What is resistance, current, and voltage?• Where is there more current and voltage – in a

series circuit or parallel circuit?• Will electricity continue to flow if the circuit is

broken in a parallel circuit? A series circuit? Why or why not? Use a diagram to help explain.

• Time: 15 minutes

Activity 1• Read through rules on pg. 456-457• Connect various resistors from the box to the

battery source• Measure the voltage and current for the

different resistors• What happens if you have more than 1 resistor?• Record your data• Time: 30 minutes

Activity 2• Graph the following data. What will be on

the x- and y-axes? What does the slope represent?

• Time: 20 minutes

Resistor value (Ω)

Voltage (V) Current (A)

3 1.5 0.53 3 13 4.510 1.510 310 4.515 1.515 315 4.5

Activity 3

• What is the relationship between resistance, voltage and current?

• Try to write an equation that represents the relationship

• Think: how do you calculate slope?• Time: 5 minutes

Activity 4

• Ohm’s Law Calculations:• Example: Calculate the resistance in Ohms of

a 9V battery that carries a current of 3A.• Complete the calculations questions

• Time: 20 minutes

Closing and Homework

• Read the “For you to read” on pg. 459• Physics to go, #1, 3, 4

Day 4: Load Limit

Day 5: Who’s in Control (60 minutes)

Day 6: Cold Shower

Day 7: Pay Up

Day 8: More for Your Money