Before the invention of the light bulb, illuminating the world after the sun went down was a hard troublesome, dangerous task. It took many candles and, oil lamps, while quite affective were known to leave annoying soot on anything in the same room as them.
In the mid 1800’s the science of electricity really started to move in a positive direction, inventers everywhere were dong their best to find a practical in expensive home lighting system. Two scientists discovered it at around the same time. Englishman Sir Joseph Swan and American Thomas Edison, and within 25 years, millions of people around the world had installed lighting in the form of electricity in their homes. This new easy to use technology was so innovative that the world never looked back. The mind blowing part of it all is that the light bulb is really easy to understand and not complex.

Light Basics:
Light is a form of electricity that is released by an atom. It is made of small particles that have energy and momentum but no mass. These particles are called light Photons, are the most basic unit of light.
Atoms release light photons when their electrons get excited. Electrons have different levels of energy, depending on several factors. Theses factors are the electrons speed and its distance form the nucleus of the atom. As you know electrons exist in levels inside orbitals around the nucleus of the atom. You also know that in most cases, electrons with greater energy exist in orbitals farther away from the nucleus. You should remember that when an atom loses or gains energy, this change is shown by a movement of electrons. When something passes energy to an atom, an electron may be temporarily to a higher orbital, putting it farther away from the nucleus. The electron stays in this position for only a fraction of a second; almost instantly the electron is drawn back toward the nucleus to its original orbit. As it returns to its orbit the electron releases the extra energy in the form of a photon, sometimes a light photon. This process is shown in the following diagram.

The wavelength of emitted light determines color, and depends on how much energy is released. The amount of energy released depends on the particular position of the electron. Different types of atoms release different types of photons. The color is determined by the type of atom that is producing the photons.
The Bulb:
Light bulbs are very simple structure. At the base they have two metal contacts, which connect to the ends of an electrical circuit. The metal contacts are connected to two stiff wires, which are attached to a thin metal filament. The filament sits in the middle of the bulb and is held up by a glass mount. The wires and filament is contained on a glass bulb, which are filled with inert gasses such as argon. See Diagram:

When the bulb is hocked up to a power supply an electric current flows from one contact to another, through he wires and filament. The electric current in a solid conductor is the mass movement of free electrons, or electrons that are not tightly bound to an atom, from a positively charged area to a negatively charged area. While the electrons are zipping along through the filament, they bump into the atoms that make up the filament. The energy of theses encounters vibrates or heats up the atom. A thinner conductor heats up faster than a thicker one because it is more opposed to the movement of electrons. Electrons that are bound in vibrating atoms may be boosted temporarily to a higher energy level. As they fall back to their original energy levels, the electrons give off their extra energy in the form of photons. Metal atoms give off predominantly inferred light photons, which are invisible to the human eye. However if they are heated to a high enough level around 4,000 degrees Fahrenheit, or 2,200 degrees C, in the particular case of the light bulb they will emit a large amount of visible light.
The filament in a light bulb is made of al long extremely thin strip of tungsten metal. In a typical 60 watt bulb the filament is about 6.5 feet long but only one hundredth of an inch in thickness. The tungsten is arranged I a double coil an order to fit it all in the small space. The filament is would up into a coil until it is less than an inch long. Tungsten is used in almost all incandescent light bulbs because it is an ideal filament material.
The Right Materials:
Metal must be heated to extreme temperatures before it will emit a useful amount of visible light. Most metals will melt before reaching such high temperatures; the vibration will actually break apart the unbending structural bonds between the atoms so that the metal becomes a liquid. Light bulbs are manufactured with tungsten because it has a really high melting point. Tungsten will catch on fire at extremely high temperatures under the right circumstances. Combustion is caused by a reaction between two chemicals it is set off when one of the chemicals has reached its ignition temperature. The filament in a light bulb is stored in a sealed oxygen free chamber to prevent combustion. In the first light bulbs they sucked out nearly all the air causing a near vacuum, therefore the material could not combust. The problem with this approach was the evaporation of the tungsten atoms. At those high temperatures the tungsten atoms would sometimes break free of the filament and fly into the air. In a vacuum bulb the freed atoms collect on the glass and reduce the quality of light produced. In the modern light bulb, argon and other inert gasses greatly reduce the loss of tungsten. When a tungsten atom evaporates it will most likely crash with an argon atom and bounce right back to the filament, where it will most likely rejoin the solid structure.