All About Light Bulbs

How does it work?

The Light bulb:

Although Thomas Edison is credited with the discovery of the light bulb, he actually only improved on old patents and was the first person to successfully keep a light bulb lit for more than a few seconds in 1879. Since then, the common light bulb most people use has not really changed that much! Now there are more energy efficient lights that can save thousands of hours of electricity that is made from coal burned in power plants.


How does a light bulb emit light?

When the atoms in the filament become excited from the electricity, the electrons in those atoms jump to a different electron cloud (imagine the nucleus is earth and the electron clouds are the layers of the atmosphere). When the electron jumps to the next cloud, a small photon of light is emitted. Many atoms being excited at once causes more light. The more clouds the electron jumps at a time, the brighter the light. This is the process of going from electrical energy to radiant energy.


Which light bulb?

The usual light bulb we all think of is known as an Incandescent bulb. The glass casing houses a gas such as argon and/or nitrogen. The filament is made up of tungsten which heats up to 4,500 degrees. Most of the electrical potential actually makes way more heat than light (90% of the electricity goes to making heat!), making incandescent bulbs have a shorter life span. This is also a good reason to switch to energy saving bulbs as well.


Light Emitting Diodes (LED) work a little differently because they have no filament so they don’t burn out like incandescent lights, they last thousands of hours more. Instead, they have semiconductor material built into the circuit. These bulbs are revolutionizing the HDTV industry because the TVs can be so much thinner.


Halogen bulbs also use a tungsten filament, but the bulb its self is made of quartz instead of glass because the filament is so close to the casing that it would melt glass! Instead of argon or nitrogen, these bulbs use gasses from the halogen group of the periodic table of elements. The interesting thing about the halogen gases is that when they come into contact with the tungsten atoms burned into vapor, it actually replaces them on the filament, creating a longer life span.


Compact Fluorescent Light bulbs (CFL) are the cousin to the long over head fluorescent bulbs in office buildings. The compact version is spiral shaped and contains argon and mercury vapor. Since CFLscontain the toxic mercury vapor, make sure you follow the EPA’s 4 step clean up process should a bulb break (shown below). CFLs also use 75% less energy than incandescent bulbs! If every house in Americaswitched to CFLs, the country would save enough energy in one year to power 3 million homes! [source: ENERGY STAR]. Save yourself some money too! The average switch to CFL can save $30 in electricity over the lifetime of the bulb. So even though they cost $2.00 more than the cheaper variety, they still save you money in the long run. And talk about a better lifespan! These bulbs work for approximately 10,000 hours vs 800-1200 hours for an incandescent bulb.


The U.S. Environmental Protection Agency (EPA) recommends following four easy steps:

  1. First, turn off your central heating or cooling system so fumes aren’t moved from one room to another. Then open up the windows and let the room ventilate for 15 minutes.
  2. Next, it’s time to clean up the broken bulb. Put on gloves to make sure you don’t touch any of the mercury powder. Use a piece of cardboard to scoop up large pieces of glass. Switch to sticky tape to pick up small fragments and shards. Don’t use your vacuum cleaner, and make sure all broken pieces, tape and cardboard are placed in a plastic bag.
  3. Finally, wipe the area with a damp paper towel and place the used towel in the plastic bag, as well.
  4. Seal the bag and immediately throw it away.