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Investigating Lightbulbs

Lesson 2:

From Unit Alternative Energy Sources

Lesson

Handouts

Academic Standards

Philanthropy Framework

6th-8th Grade

Subjects:

Language Arts, Library / Technology, Math, Philanthropy, Science and Social Studies

Key Words/Concepts click to view

ELA:	Star-Ledger; Informational Media; Questioning
MAT:	Graphs/Charts/Tables
PHIL:	Common Good; Environmental Stewardship; Problem Solving; Responsibility; Stewardship
SCI:	Analyze; Compare/Contrast; Conservation; Critical Thinking; Data Collection/Organization; Electricity; Energy; Measure; Observation
SOC:	Environment; Resources

Purpose:

Through a scientific investigation, the students compare features and costs of two types of lightbulbs. This lesson helps the learners understand how energy efficiency choices can impact their family energy costs and reduce the amount of energy consumed.

Duration:

Two 50-Minute Class Periods

Objectives:

The learner will:

complete a lab activity comparing two lightbulbs.

compare the appearance, cost, and brightness of incandescent and compact fluorescent lightbulbs.

calculate the costs of each type of lightbulb (cost to buy and cost to use).

define stewardship as the careful and responsible management of something entrusted to one's care.

brainstorm the environmental benefits of using one type of lightbulb.

discuss ways to encourage others to use one type of lightbulb.

Materials:

Newspaper headlines related to the price of electricity (see Teacher Preparation)
Student copies of Attachment One, Lights Light Up Your Life Data Sheet
Graph paper
Each lab group (or one per class for a demonstration) needs the following supplies:
Calculator
Light meter (if available)
Two thermometers (room or lab/see this website for example)
Compact fluorescent lightbulb with power rating (Watts) stamped on the side
Incandescent lightbulb with power rating (Watts) stamped on the top
Two standard sockets or lamps
Tape measure, yard stick, or meter stick

Handout 1: Lights Light Up Your Life Data Sheet

Teacher Preparation:

Rather than obtaining supplies for each lab group, you may set up the light demonstration in a central location for groups to observe. Or set up stations for different observations.
Before the students arrive, access Star-Ledger online to download recent headlines and lead sentences about the price of electricity. Type "electricity cost" into the Star-Ledger search field. Print (or read aloud) three or four recent headlines for students to read and discuss.
Save the packaging and price tags from the lightbulbs so students can compare the costs to purchase each type of lightbulb. The packaging also includes lumens (light output) and the life expectancy (number of hours it will last).
If possible, contact the electric company (or look at an electric bill) to find out the cost of electricity per kilowatt-hour. If you are unable to obtain the price, the worksheet contains a price per kilowatt-hour for an equation (but it won't be a current price).

Instructional Procedure(s):

Anticipatory Set:

As students enter the room, they read several newspaper headlines/lead sentences posted on the classroom wall related to electricity. (See Teacher Preparation above.) Discuss the relevance of the headlines. What is the global concern related to electricity? Relate this topic to the students tracking electricity usage for the past week.

Show learners one incandescent lightbulb and one compact florescent lightbulb (CFL). Ask the learners to describe the difference between the two lightbulbs. Allow learners time to share their answers and discuss the appearances (and their prior knowledge) of the two lightbulbs. On the board, write the prices per package and the number of bulbs in each package. Ask the students to calculate the price per lightbulb. Look at other features and claims on the packaging. Tell the students that today they are going to investigate the real costs of using these two types of lightbulbs.

Remind the students that in the previous lesson they discussed the concepts of conserving energy and stewardship. Tell them that in order to conserve energy and reduce waste, they should promote the use the most efficient lightbulbs in their houses and other buildings at school and in the community. Tell them that the Energy Star group claims the CFL is ten times more efficient than the incandescent lightbulb. But we should use science to prove that to ourselves before we commit to spending more money per lightbulb.

Distribute Attachment One: Lights Light Up Your Life Data Sheet to each student. They will use this lab sheet to step-by-step compare and contrast several features of these two lightbulbs. Ask each learner to make predictions about the lightbulbs in the prediction section of the worksheet.

Arrange learners into groups (groups of four learners works the best for this investigation). Distribute the materials for each group: two light sockets, one incandescent bulb, one compact fluorescent bulb, two room thermometers, one light meter, and a meter stick. If you choose to do this as a demonstration (and reduce the number of supplies needed), set up the lights where all groups can see them. Representatives from each group may go to the demonstration area, as needed, to collect data and then return to their lab groups.

Tell the learners to carefully read and follow the instructions on the lab sheet to do the investigation.

Allow a reasonable amount of time for the learners to do the investigation. Ask each group to choose a representative to report the group's conclusions.

Bring the class back together and discuss the results of the lab. Ask each group's representative to report their findings and conclusions. The groups should have found that the compact florescent lightbulb costs less to operate and generates less heat, thus saving energy while producing equivalent light. (If you do not have a light meter, compare the brightness of the bulbs using the information on the packaging.)

Ask the students how they, as consumers, can use this information. Discuss the cost, impact on the environment, and other efficiencies. Help students articulate the idea that by using less energy when lighting their homes they are helping to conserve resources. Make sure they understand that energy conservation is important because electricity is often produced by non-renewable and polluting fossil fuels (coal and oil). Guide them to recognize that it is also the responsibility of each citizen to be good stewards of resources. Using more efficient lighting is one way to conserve energy.

Encourage the students to think of ways they can be advocates for using CFLs. They may recognize that the cost of the CFLs will be prohibitive to some families, but the cost savings in the long run will help them. Would teaching other people in the community about the lightbulbs help the whole community and themselves? Discuss opportunities for raising awareness or assessing needs. (This may become part of their final project at the end of lesson three.)

This lesson adapted from Learning to Give 6-8 lesson "Lights Light Up My Life" http://www.learningtogive.org/lessons/unit384/lesson2.html

Assessment:

Assess the learners’ group participation. Collect the completed Attachment One: Lights Light Up Your Life Data Sheets and assess these for completeness.

Extension:

Have learners complete the Energy Star Lighting Quiz found at the following web address.
http://www.energystar.gov/index.cfm?
c=ilg.pr_lighting_quiz_index

Bibliographical References:

Star-Ledger New Jersey. http://www.nj.com/starledger/

Lesson Developed and Piloted by:

Betsy Flikkema
Associate Curriculum Director
The LEAGUE Curriculum by Learning to Give

Barbara Dillbeck
Curriculum Director
The LEAGUE Curriculum by Learning to Give

Jessica Wagenmaker
Holton Public Schools
Holton Middle School
Holton, MI 49425

Handouts:

Handout 1Print Handout 1

Lights Light Up Your Life Data Sheet

NAME: __________________________

Make individual predictions (each member of the group makes his/her own predictions).

Which lightbulb will generate the most heat? _______________________
Which lightbulb will generate the most light? _______________________
Which lightbulb will use less energy? _____________________________
Which lightbulb will cost less to operate? __________________________
Which lightbulb will last longer? _________________________________

Working with your group, obtain the following materials:
two light sockets, one incandescent lightbulb, one compact florescent lightbulb, a light meter, a yard/meter stick, and a calculator
Use care when handling these bulbs. They break easily.
As a group complete the rest of the data sheet.

Step 1

Screw an incandescent lightbulb into one of the light sockets, and screw a compact florescent lightbulb into the other light socket. With the power off, compare and contrast the two lightbulbs. How are they the same and how are they different?
Record your observations:

_________________________________________________________________________________________

Step 2

Place your sockets 24 inches (61 cm) apart. With the power off, place a thermometer a few inches (cm) away from each lightbulb. Read and record the temperature of the air around the lightbulbs.

Incandescent _____________ Fluorescent _______________

Step 3

Turn on the power to the lightbulbs. Describe each lightbulb again. Do not touch the lightbulbs. Record your observations:

_________________________________________________________________________________________

Step 4

Place a thermometer a few inches from each lightbulb. Measure and record the temperature of the air around each lightbulb every minute for seven minutes.

Time (minutes)	Temperature around Incandescent lightbulb (in Fahrenheit or centigrade)	Temperature around Compact Fluorescent lightbulb (in Fahrenheit or centigrade)
0 (from step 2, above)
1
2
3
4
5
6
7

Step 5

Plot the data from the table above on graph paper. Place time on the x-axis and temperature on the y-axis. Write TWO observations below.

_________________________________________________________________________________________

Step 6 (Note: If a light meter is not available, skip to Step 8.)

Using a light meter, measure the light given off by each type of lightbulb. Record the level of emitted light in 1-foot (30cm) intervals, from 1 foot (30 cm) to 12 feet (3.6 m). Record the data on the table below.

Distance from lightbulb in feet (metric)	Incandescent bulb level in feet (meter)	Compact Fluorescent bulb level in feet (meter)
1 foot (30 cm)
2 feet (60 cm)
3 feet (91cm)
4 feet (1.2 m)
5 feet (1.5 m)
6 feet (1.8 m)
7 feet (2.1 m)
8 feet (2.4 m)
9 feet (2.7 m)
10 feet (3.0 m)
11 feet (3.4 m)
12 feet (3.6 m)

Step 7

Plot the data from the table above on graph paper. Place distance on the x-axis and light level on the y-axis. Compare your two graphs. Write TWO observations below.

____________________________________________________________________________

_________________________________________________________________________________________

Step 8

Record the price of each lightbulb below.

Incandescent _____________ Fluorescent _______________

Step 9

Determine the amount of electrical energy (kilowatt-hours) used by each lightbulb in one hour. Multiply the lightbulb's power rating (Watts) by .001 (or divide by 1,000). A power rating is printed on the top or stem of the bulb. Record the kilowatt-hours below.

Incandescent _____________ Fluorescent _______________

Step 10

Figure out the amount of energy each of the lightbulbs would consume if they were left on for 10 hours. Use the kilowatt-hours from step 9 in this equation to figure it out: kilowatt-hours x number of hours = amount of energy used.

Incandescent _____________ Fluorescent _______________

Step 11

Figure out how much the amount of electricity from step 10 costs. Use the price per kilowatt-hour your teacher obtained or use $0.07 per kilowatt-hour. What is the daily cost (10 hours) to operate each lightbulb?

Incandescent _____________ Fluorescent _______________

Step 12

Answer the questions below:

1. Which lightbulb generated the most heat? ________________
2. Which lightbulb generated the most light? ________________
3. Which lightbulb used the most energy? ______________________
4. Which lightbulb costs less to operate? _______________________
5. Which lightbulb costs more to operate? ______________________
6. How much energy and money can you save each year by replacing one incandescent lightbulb with one compact fluorescent light bulb? _______________

7. How long would it take for energy savings from the fluorescent light bulb to cover the additional cost of the bulb? (You will need to know the cost of each lightbulb.)

____________________________________________________________________________________

8. After this lab, which light bulb will you choose to have in your house and why?

____________________________________________________________________________________

9. In your opinion, should the government pass a law requiring the use of compact fluorescent lightbulbs? Why or why not?

____________________________________________________________________________________

____________________________________________________________________________________

Academic Standards:

State/Country:

Philanthropy Framework:

Unit Contents:

Overview:Alternative Energy Sources Summary

Lessons:

1.: Measuring Energy Use
2.: Investigating Lightbulbs
3.: Energy Action Plan