Lightbulbs offer one of the most basic examples of energy efficiency. Compact fluorescent lightbulbs (CFLs) may use up to 75 percent less energy and last 10 times longer than an incandescent lightbulb. Many students already know that CFL lightbulbs are more environmentally friendly compared to incandescent bulbs, but they may not realize why there is a difference. Conducting a hands-on investigation with both types of bulbs can provide students with a memorable experience that allows them to see firsthand the efficiency difference—through the measurement of temperature change—between the two bulbs.

Watch this video of 4th and 5th grade students in San Diego, California—a working class community. The purpose of this classroom video is to see students investigate lightbulbs and describe what they learn about efficiency.

For additional classroom context, video analysis, and reflection opportunities, read the Picture of Practice page for "Energy Efficiency of Lightbulbs" in the Energy Potential Environmental Literacy Teacher Guide, page 107.