An incandescent lamp, otherwise known as a light bulb, is a form of electric light. Incandescent bulbs are so effective that they have been widely adopted around the world for all sorts of lighting applications, from illuminating the inside of an oven to providing safety illumination for parking lots. The mechanics of the incandescent lamp are remarkably simple, and the design has not deviated very much from the earliest prototypes.
This type of electric light works by subjecting a very fine filament to an electric current. If the electric current is high enough, it will heat up the filament and excite the atoms inside, eventually causing them to give off light. The property of incandescence, in science, involves glowing in response to heat, and the incandescent bulb is probably the most famous demonstration of this property.
Humphry Davy is often given credit for first demonstrating that if a metal filament was subjected to an electrical current, it would give off light. A bit of trial and error occurred after his demonstration before the incandescent lamp was introduced. First, people had to find a metal which would make an effective filament, and then they had to address the common problem of oxidation. An exposed filament wouldn't last very long, necessitating the creation of a vacuum around the filament, which meant that someone have to develop an envelope to enclose it. A glass bulb was found to be ideal, and the incandescent lamp was born.
The modern incandescent lamp is usually filled with an inert gas, rather than operating in a vacuum. The life of a light bulb can be quite impressive, with bulbs tending to last longer when they are left continuously on, rather than being turned off and on frequently. Life of the bulb can also be influenced by the types of light fixtures it is used in, the amount of light it is intended to produce, and factors such as trauma; the filament will often break if an incandescent light is jostled while it is on, for example.
Incandescent lamps come in a wide variety of configurations. The intensity of the light can be varied by adjusting the wattage and the composition of the bulb; clear bulbs will give off bright, clear light, for example, while frosted bulbs will mute the light. Size and shape can also be varied, with some bulbs being designed to mimic candles, while others are intended to fit into unique or small spaces, so they require an unusual shape and attached socket to connect with a source of electrical current.