Re: How can the amount of lumens be different for bulbs with the same wattage?

Dear Casey, I think that you have a very good experiment to conduct. So lets see what is causing your confusion. Look at the two terms in your question. The wattage of any electrical device is a measure if its power. ThatŐs the amount of electric energy that it will use in a certain amount of time. One watt is the rate of one joule each second. On the other hand, lumens refer to the amount of light that is given off by something. Lumens are included in the description of light bulbs because thatŐs why most people buy them. Other electrical appliances are used to give us either heat or motion or some combination of useful energy. Incandescent light bulbs give off light because their filament is first made very hot. ThatŐs a little wasteful, at best, and really undesirable in the summer. CFL type bulbs or their older, longer cousins cause mercury gas to radiate light at a much lower temperature and are more efficient. LEDs are even more so. Even different bulbs within a grouping can vary in the type of light they release or in the amounts of different colors. If this seems odd, consider an electric stove. It is used mostly for cooking by heating and can use electric energy at the rate of up to six or eight thousand watts. But it doesnŐt make a very good lamp to read by. However, a small flashlight does give enough lumens to read; but would take a really long time to bake a cookie. So, I think you are correct to try to equalize the lumens in your three types of lights. The differing amounts of watts needed to get there is an example of the difference in the conversion of electrical energy to radiant energy. These choices allow us to determine the desired levels of waste heat and/or cost of purchase and operation. Good luck in your investigation. Gene Ewald