Wouldn't the face that you cannot achieve a perfect vacuum make measuring the true speed of light to exactly c impossible?
Home experiments to derive the speed of light?
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Re: Home experiments to derive the speed of light?
#12Wouldn't the face that you cannot achieve a perfect vacuum make measuring the true speed of light to exactly c impossible?
Not really, no. The speed of light in air is very nearly identical to the speed of light in a vacuum. Wikipedia gives the refractive index of air as 1.0003, which is the ratio between the speed of light in a vacuum and the speed of light in air.
The use of air as a medium rather than a vacuum is unlikely to be a significant source of error in an amateur measurement of c.
Re: Home experiments to derive the speed of light?
#13You don't use experiments to 'derive' the speed of light. You use Maxwell's equations.
Re: Home experiments to derive the speed of light?
#14You don't use experiments to 'derive' the speed of light. You use Maxwell's equations.
Well, if you're going that way, I'd say you can't derive it at all, because the speed of light is a defined constant.