One of the most amazing and influential changes in the nineteenth century was the development of electric lighting. Before the light bulbs were widely available, people illuminated homes and offices with candle light, oil lamps, and sometimes, gas. These lighting sources were not very bright and did not really allow for the development of a true "night life" in America or anywhere in the world. Study the inventions and discoveries on the slides below, which describe how Americans found it easier and easier to stay up late.
|
Kite and Key You probably know that Founding Father Benjamin Franklin discovered electricity through his famous kite-and-key experiment in 1752. However, nearly 100 years would pass before electricity was fully utilized. That's because the problem to be solved was never one of generation, but of delivery—with two difficulties creating the largest barriers. First, different kinds of electrically powered devices required different voltages and thus separate lines. Second, the generators of electricity had to be located close to their loads (the objects they powered). A new system was required to deal these difficulties.
Before Light Bulbs The first electric light was pioneered by Humphrey Davy in 1802 and was called the arc light. To produce light, Davy used wires to connect an electric battery to a piece of carbon. When electricity shot through it, the carbon would glow. The light that was produced by arc lights was often hundreds of times more powerful than that of modern light bulbs. From the 1870s through the 1890s, arc lights were grouped together and placed on tall structures called moonlight towers. Often over a hundred feet high, moon light towers could illuminate entire city blocks. For example, the city of Austin, Texas, perhaps in response to a series of ghastly nighttime urban murders, installed moonlight towers to make streets safer at night. One of the problems with arc lights, though, was the heat they produced. They burned at 7000 degrees, hotter than anything on earth other than a nuclear explosion. Indeed, they burned at such a high temperature that the carbon burned out every day and had to be replaced by workers who would climb the towers.
Incandescent Lighting Because he knew that arc lights were far too bright and dangerous for use in homes and businesses, Thomas Edison not only patented the light bulb as a device—he also created an entire system for delivering light. While there were many designs for light bulbs in the nineteenth century, it wasn't until 1879, after Edison applied for two light bulb patents, that electric light would become widely accessible. Edison's incandescent light bulb consisted of a sealed glass bulb containing a filament through which an electric current was sent. The glass bulb created a vacuum necessary to keep oxygen out. Without the vacuum, the filament would burn up just as the carbon in moonlight towers had. Edison tested many different filaments before settling on one made from bamboo. While the filament does get hot (up to 500 degrees Fahrenheit), it does not reach a temperature even approaching that of the arc lamps. For this reason, Edison's light bulb was far more practical than the arc lamp. An incandescent bulb using a carbonized bamboo filament could function for 1200 hours.
Electric Systems Edison later founded a "utility," an investor-owned power generation station in Manhattan that supplied 85 customers who owned light bulbs. The invention of the bulb was simply one part of this project. Customers and investors had to be found, prices established, and conduits constructed to send power into homes. In this case, the wires to supply the electricity ran under Manhattan. Thus, streets had to be upturned, which required the cooperation of public officials.
Currents and Transformers Two additional developments made electricity available to larger groups of customers. In the 1880s, George Westinghouse argued that direct current generation didn't produce a voltage high enough to power large systems, or to allow transmission over long distances. He advocated for an approach that would use alternating currents instead. In direct current transmission, the current flows only in one direction. In alternating-current transmission, the current flows forwards and backwards, producing additional voltage. To conduct electrical energy at higher voltages, a new technology called a transformer was developed. Transformers could conduct two or more circuits through magnetic induction: A current in one coil of the transformer produced a varying magnetic field, which induced a voltage in a second coil. And power moved between the two coils because of the magnetic field. Transformers were crucial to industrialization because they facilitated the transfer of alternating currents—and therefore electricity powerful enough to supply factories.
Night Shift It was perhaps mass production that benefited most from the invention of light bulbs: round-the-clock labor became truly possible for the first time in human history. In this sense, one could argue that the impact of the light bulb on workers was both negative and positive. Traditionally, night time darkness shut down the work of most farmers and factory workers. Once humans figured out how to harness electricity for the production of light, however, work never had to end, especially in factories and offices. It was relentless and ceaseless. |
 |
What were the steps that made late nights and longer hours at the factory more possible? See if you can put these stages of electricity and lighting development in the correct order.
|
Benjamin Franklin's kite-and-and key experiment
Edison's development of a Manhattan electric utility
the development of transformers
the development of the arc lamp and moonlight towers
Edison's patents for the incandescent light bulb
|
1
2
3
4
5
|
