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The speed of light in air was first accurately found using earthbound equipment (as opposed to astronomical techniques) by Hippolyte Fizeau in 1849, using ideas that were mooted many years before by carious scientists - including Galileo. in Fizeau's experiment a beam of light was directed at a mirror several thousand metres away. On the way from the light 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. The whel was manipulated until the beam was detected both on the outward and return journey. 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. Using this method Fizeau reported the speed of light as 313,000 kilometres per second. In 1926, Michelson used a rotating prism to measure the time it took light to make a round trip from Mount Wilson to Mount san Antonio in California USA, a distance of about 22 miles (36 km). The precise measurements obtainable from this more sophisticated arrangement yielded a speed of 186,285 miles per second (299,796 kilometres per second), very close to the accepted figure today - a figure that is obtained by much more sophisticated and aurate techniques. Don't forget, though, that the speed of light will vary considerably depending upon what medium the light is passing through. The above figure represnted the speed of light in air; in a vacuum it is slightly faster, but in dense media like glass or quartz, the speed of light is considerably reduced.

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1600s Galileo attempted to measure the speed of light using blank?

Galileo attempted to measure the speed of light using lanterns positioned at known distances and observing the time it took for light to travel between them. He would uncover the lanterns simultaneously and use a telescope to try and detect any delay in the light reaching his eyes. However, his methods were not sensitive enough to accurately measure the speed of light.


Why did early experimental attempts to measure the speed of light fail?

If you want to measure the speed of something, you first have to recall that speed is (distance traveled) divided by (time to travel the distance), and then you realize that you have to measure the distance it travels and the time it takes to travel that distance. If it happens to be the speed of light, then you immediately have a serious problem. The speed of light is so great that ... -- If you pick a distance that's easy to measure, then the time is impossibly short. For example, if you pick ten miles, then you have to accurately measure 0.00005368 of one second, which is pretty tough. -- If you pick a time that's easy to measure, then the distance is ridiculously long. For example, if you pick 0.1 second, then you have to accurately measure 18,628.2 miles, which is enormously tough. Both of these methods are theoretically and technically perfect, and completely impossible to actually use for the speed of light. You have to invent whole new clever ways to measure speed.


What did albert mitchelson use to measure the speed of light?

Two mountains. He sent pulsed light from one mountain to a reflector on another. The travel time was measured and divided by two.


If the universe is infinite then surely there can be no such thing as the speed of light as there is no start point and no end point?

Logically incoherent. Who said you need to use the entire universe to measure the speed of anything ? Simply define your own start and end points, and then measure the time light takes to travel between them. The points can be as mundane as two opposite walls of the restroom in your laboratory.


What can people use to measure the speed of the wind?

Anemometer.

Related Questions

What might the astronauts use to get up to light speed instead of engines?

Sails that are pushed by light is one concept.


What would the first astronauts use to get up to light speed in stead of engines?

None. No astronaut or man-made object has ever gotten close to the speed of light. It is impossible for an object to actually travel at the speed of light.


Who is the scientist use the light year to measure the speed of light?

It doesn't work that way. The light-year is not used to measure the speed of light. It works the other way round: First, the speed of light is determined through other methods, then the distance called a light-year is calculated based on that measurements.


1600s Galileo attempted to measure the speed of light using blank?

Galileo attempted to measure the speed of light using lanterns positioned at known distances and observing the time it took for light to travel between them. He would uncover the lanterns simultaneously and use a telescope to try and detect any delay in the light reaching his eyes. However, his methods were not sensitive enough to accurately measure the speed of light.


What did the astronauts use to get up to the speed of light only in stead of engines?

this thing dose not give u the answer!!!!!! does is spelled D-O-E-S smart 1


Why did early experimental attempts to measure the speed of light fail?

If you want to measure the speed of something, you first have to recall that speed is (distance traveled) divided by (time to travel the distance), and then you realize that you have to measure the distance it travels and the time it takes to travel that distance. If it happens to be the speed of light, then you immediately have a serious problem. The speed of light is so great that ... -- If you pick a distance that's easy to measure, then the time is impossibly short. For example, if you pick ten miles, then you have to accurately measure 0.00005368 of one second, which is pretty tough. -- If you pick a time that's easy to measure, then the distance is ridiculously long. For example, if you pick 0.1 second, then you have to accurately measure 18,628.2 miles, which is enormously tough. Both of these methods are theoretically and technically perfect, and completely impossible to actually use for the speed of light. You have to invent whole new clever ways to measure speed.


How can you measure the speed of light accurately?

A way to measure the speed of light pretty accurately is by conducting an experiment in which you use chocolate and a microwave. To find out more about this experiment you can go on everything2.com. its quite interesting. In fact im thinking of making this my science fair project!!!


What is use by scientist to measure the distance light travel in one year?

Scientists don't measure the distance light travels in one year. They calculate it by measuring the speed of light. The speed is 300,000,000 meters/sec. and can be measured in the laboratory with a rotating mirror apparatus. To get the distance traveled by light in one year you multiply the speed (above) by the number of seconds in a year. The answer will come out in meters and is also called one light year.


How do you use light speed in a sentence?

A asteroid travels at the speed of light.


Do you use a hydrometer to measure wind speed?

To measure wind speed you use an anemometer. These are sometimes called wind meters. Meteorologists use anemometers to help predict weather.


Do you use a stop watch to measure speed?

no you use a stopwatch to measure elapsed time.


What did albert mitchelson use to measure the speed of light?

Two mountains. He sent pulsed light from one mountain to a reflector on another. The travel time was measured and divided by two.