Do you think that all light bulbs use the same amount of energy?

Some light bulbs are known to use less energy and release less greenhouse gases into the atmosphere. Try this activity to see if different light bulbs produce the same kind of light and the same amount of heat.

What You Need

• An incandescent bulb*
• A compact fluorescent light bulb (CFL)*
• A LED bulb*
• Thermometer

*Make sure that the light bulbs all have the same number of lumens (a lumen is a unit measure of light).

What To Do

• Have an adult place the fluorescent bulb in the lamp and then turn it on. Look at the light that is produced.
• Hold a thermometer about 6 inches above the bulb for 1 minute and then read the temperature. Turn off the lamp and let the bulb cool.
• Have an adult remove the fluorescent bulb and replace it with an incandescent bulb. Follow the same procedure.
• Have an adult remove the incandescent bulb and replace it with a LED bulb. Follow the same procedure.

What Did You Find?

• What was the difference in the light produced by each bulb?
• Which bulb used the least amount of heat?
• Which is the most energy efficient of the three bulbs?

While both incandescent bulbs and CFLs give off heat as well as light energy, CFLs give off less heat.  CFL’s are known to be much more energy efficient than standard incandescent light bulbs. However they contain mercury, a toxic chemical, so you need to be really careful if you have them around the house.  The new LED bulbs are safe, energy efficient and completely environmentally friendly. Plus they are available in a variety of cool colors.

AlternativeE.org is a website about alternative energy solutions. See how they compared light bulbs.