While regular lights and laser lights both share the characteristic of being a type of light, most of the similarity ends there. They are actually very different.
The typical incandescent light bulb produces a broad spectrum of light, meaning that it puts out the entire visible spectrum of light. This is why these bulbs appear to be white. Lasers put out a specific wavelength of visible light. This wavelength is what dictates a laser's color, as seen by the eye.
An incandescent bulb puts out light in every direction at the same time. This is why it lights entire rooms when on. Lasers emit light in a single, narrow beam, lighting only a small area.
A great percentage of the energy used by a standard light bulb is wasted as heat. Lasers are much more efficient because more of the energy used to create the light is focused in the beam. This is why some lasers can burn or even cut.
Incandescent light is produced by simply running alternating current through an electrically resistant filament. As the filament gets hotter, it begins to glow, emitting visible light. Laser light is produced by electrically exciting atoms until they release energy in the form of a photon, which is what we see.
While there are incandescent bulbs with brightness levels capable of being painful to look at, few except the very brightest can cause permanent eye damage. The intensity of the light produced by a laser beam can permanently blind a person in seconds.
- "Eyewitness: Light;" David Burnie; 1999
Image by Flickr.com, courtesy of Nicki Varkevisser