how to measure the speed of light using fizeau's method?

Question

I have read several different articles about fizeau's experiment and I understand most of the concept but I would like to know how he acually did it. In explaining please answer these questions:
-what type of light source did he use?
-was the light source pulsating or was it continuous?
-If the cog is spinning so fast and had hundreds of teeth, how can he determine if light passes through the same spacing?

Answer 1

The first successful measurement of the speed of light using an earthbound apparatus was carried out by Hippolyte Fizeau in 1849. Fizeau's experiment was conceptually similar to those proposed by Beeckman and Galileo. A beam of light was directed at a mirror several thousand metres away. On the way from the source to the mirror, the beam passed through a rotating cog wheel. At a certain rate of rotation, the beam could pass through one gap on the way out and another on the way back. But at slightly higher or lower rates, the beam would strike a tooth and not pass through the wheel. Knowing the distance to the mirror, the number of teeth on the wheel, and the rate of rotation, the speed of light could be calculated. Fizeau reported the speed of light as 313,000 kilometres per second. Fizeau's method was later refined by Marie Alfred Cornu (1872) and Joseph Perrotin (1900).

Based upon all my investigation the beam of light had to be continuous for this experiment to work. I have not been able to identify the light source however some of the links below identifiy... a candle. lol

Answer 2

The rotating reflect approach must be attainable, however I have not ever attempted it. See the supply. Because mild actions so speedy, you want the desk bound reflect as a long way away as feasible; undoubtedly enormous quantities of ft and ideally many miles. It would require EXTREMELY distinct pointing of the laser to hit that far away reflect after which be competent to discover the returning mirrored image. Also, because the rotating reflect turns, the outgoing mild beam course will difference in order to overlook the desk bound reflect by and large, so the returning mirrored image might be a pulsing mild, on best throughout the fast time the mirrors are covered up flawlessly and stale the relaxation of the time. This can also be expanded slightly through having some thing like a disco ball, with many mirrors, in order that you get a noticeable go back mirrored image greater than as soon as in keeping with rotation. Any method you appear at it, this can be a rough test to do. The toothed wheel approach is less difficult, however you want LOTS of SMALL enamel and an overly FAST ROTATION. Since mild travels 186,000 miles a moment, if the far away reflect is one million mile away you want the wheel to transport from an area to the closest teeth in two/186,000 seconds, or approximately 10 millionths of a moment. With a one hundred teeth wheel, that's approximately 60,000 RPM!

Answer 3

Fizeau Speed Of Light

Answer 4

In answer to the last question, if the wheel starts out slowly, the light will always return through the same gap. As the wheel speed is increased, the light will dim as the returning beam is intercepted by the next tooth. Thus, we can be sure that the time interval is the tooth-to-gap spacing divided by the circumferential speed of the wheel. If the wheel speed is increased, the light will become brighter again as the returning beam passes through the next gap; further increase in speed will cause another null as the second tooth intercepts the beam. I consider it unlikely that the wheel could have been spun fast enough to see these higher-order nulls.

Answer 5

http://en.wikipedia.org/wiki/Fizeau-Foucault_apparatus

might help