Jim wrote:
Edison was so convinced that he could make a light bulb work that he lied to the public and his financial backers saying that he had a working light bulb.
In the movie version of Edison's discovery of a working lightbulb design (this is the one in which Spencer Tracy portrays the inventor), they show one of Edison's employees, not Edison, who tells the newspaper reporters that Edison already had a working filament. Edison then chastises the employee for making the premature and unwarranted announcement.
Well, I found this discussion of Edison interesting because I live in the area of New Jersey where he prefected his lightbulb. I've visited his various laboratories in the area and am still in awe of the man. Some of this original lightbulbs are on permanent exhibition at a site in Menlo Park, NJ were they erected a huge tower to commemorate his invention of the lightbulb.
A lot of people do not realize that the material that Edison first used in the lightbulb that actually held up was a simple piece of baked and carbonized cotton thread! The much more durable tungsten filaments that are found in modern lightbulbs were developed by a black inventor years later.
There is some contention as to who actually invented the lightbulb and I think I've heard of inventors in both England and Germany who made prior claims to the device. But, their bulbs, although they used incandescent filaments, could not operate for more than a matter of minutes before they burned out. Only Edison's bulb was good for thousands of hours which made it practical.
I have often wondered why Edison had not tried something like using some sort of inert gas to protect the filament from oxidation instead of a vaccuum. Maybe such gases were not readily available in the 1870's or he found the vaccuum easier to work with.
ken
On 7/6/06, I found, in any overbalanced gravity wheel with rotation rate, ω, axle to CG distance d, and CG dip angle φ, the average vertical velocity of its drive weights is downward and given by:
Vaver = -2(√2)πdωcosφ