Why does the light clock thought experiment apply to all clocks?

[jezter]

Ok, assuming the logic of why a moving light clock appears to slow down relative to the stationary observer is because the distance the moving clock photon travels is greater for the stationary observer compared to the moving observer. Now as far as i can see this logic works because a photon moves independant to it the source (i.e. despite the light source moving at (e.g.)200,000km/s, the photon will only be 300,000km/s (not 200,000 + 300,000km/s). Therefore it cannot transverse the apparent greater distance any faster, so the 'tick' of the light clock slows down (relative to the stationary observer).

But why should this logic apply to a normal watch that isnt based on a photon. I mean, its only light that's independant of the speed of its source. Wouldn't the speed of the clock hand be dependant on the speed of its source so it could travel the apparent extend distance faster to equalise the result. Or what if one replaced the light bouncing between to mirrors with a ball bearing......?

I know it does, but any help as to why would be appriciated!

[jomifl]

perhaps because you are seeing the clock with light? or did I miss something?

[sandyRoe]

Where would this leave someone who used the speaking clock?

[jomifl]

at the end of a telephone line sandy :-)

[chi-chi66]

Laughing @ jomifl :O))

[sandyRoe]

struggling to keep a straight face :-)

[rojash]

"Wouldn't the speed of the clock hand be dependant on the speed of its source so it could travel the apparent extend distance faster to equalise the result. "

In my experience, when looking at a watch, the hand doesn't travel towards the observer's eyes. Using photons to observe things is much safer than getting poked in the eye with the things themselves.

[mibn2cweus]

In addition to classical Doppler shift there is a relativistic shift in frequency at the source due to time dilation.

Consider a clock orbiting a stationary observer. There would be no Doppler shift since there is no change in distance. Time dilation however would still be evident in the slowing of the orbiting clock as its orbital velocity approached the speed of light.

[Old_Geezer]

Surely it is only a greater distance if the moving clock is travelling away from the observer ? It wouldn't account for the clock moving towards the observer. Anyway the maths surely shows it ain't that simple, or did I misunderstand ?

It is the passage of information that is limited by the speed of light. Not sure clock hands come into it.

[jake-the-peg]

Beacause of the second principle on which general relativity is based

That you cannot tell whether or not you are moving at a constant velocity relative to a point or stationary.

We're all travelling through space at an incredible speed but the laws of physics are the same to us as if we were stationary.

If the photon clock kept time differently to a wrist watch or any other clock, mechanical or biological then you could tell whether or not you were moving.

[mibn2cweus]

In spite of years trying to wrap my brain completely around it, relativity still makes my head spin.