The electric bulb

In the middle of the 19th century, the candles, oil or gas lamps and the fire from fireplaces were the only light sources in homes. The smoke, soot, and the gas expulsion put the health of people in danger. But this situation would change when the bulbs appeared. The inventor of the electric bulb was Thomas Alva edison, who made it possible that the filament of the bulb didn't melt with the help of a carbonized cotton string. But the bulbs didn't work without electricity, although Thomas solved this problem by creating an electricity-central with steam engines in New York, the first central that got the street lighting in 1882.
There are a lot of types of bulbs:

• Incandescent bulbs: They are the common bulbs. The light is produced when the electricity passes through the filament.

• Halogen bulbs: The incandescent conventional bulbs lose the light because the tungsten filament evaporates, but this type of bulbs are more durable than the others and with them is possible to consume less with clearer and brighter light.

• Bulbs with low consumption: They are an adaptation of the fluorescent tubes. They produce white light and cold, so the consumption is less than incandescent bulbs.

• Fluorescent tubes: these lamps have a tube form with mercury vapor inside. As they aren´t heat, they don´t lost energy, and consume less than incandescent bulbs.These were used for the first time in NY World's Fair in 1939.

• Neon lights: they were introduced in 1910 by the french chemist Geogers Claude. Consist in a tube, with neon gas inside and they emit a light tinted. They are used in advertising.

And finally one important question: Why do bulbs burn? Because the metal of the filament evaporates with the use, and then the filament breaks.