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?

____________________________________________________________________________________

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