ash64449 said:
That experiment demonstrates relativity of simultaneity not time dilation. It's easy enough to construct thought experiments that do demonstrate time dilation though; look for something that explains the relative doppler effect in a coordinate-independent way.
When you have a chance, dig up a copy of Einstein's 1905 paper "On the electrodynamics of moving bodies". It will give you a more systematic and formal development of this stuff while still retaining the historical flavor of Einstein's explanations.
Also, you might try Philip Wood's excellent advice:
I find no difference in what Einstein said in my book and in On the electrodynamics of moving bodies. Let me copy-paste the exact words and what i mean by it also,as a result you can help me correct. I agree that i was making wrong assumption on the exact question i asked. Let me see whether i understood or not why Time dilation takes place.
On the electrodynamics of moving bodies
Actual Print of Einstein's 1905 paper
"We have to take into
account that all our judgments in which time plays a part are always judgments
of simultaneous events"
Here Einstein said that we should consider Time as playing the part of simultaneous events.
Example(From Einstein's 1905 paper): “That train arrives here at 7
o’clock,” I mean something like this: “The pointing of the small hand of my
watch to 7 and the arrival of the train are simultaneous events.”
"We assume that this definition of synchronism is free from contradictions,
and possible for any number of points; and that the following relations are
universally valid:—
1. If the clock at B synchronizes with the clock at A, the clock at A synchronizes with the clock at B.
2. If the clock at A synchronizes with the clock at B and also with the clock
at C, the clocks at B and C also synchronize with each other"
By this he means that If the clocks satisfy this simultaneous considerations,then these clocks go at the same rate.(my words)
These words of Einstein is from the chapter Definition of Simultaneity.
Let me go to the second chapter On the Relativity of Lengths and Times.
Words of Einstein:
The following reflexions are based on the principle of relativity and on the
principle of the constancy of the velocity of light. These two principles we define
as follows:—
1. The laws by which the states of physical systems undergo change are not
affected, whether these changes of state be referred to the one or the other of
two systems of co-ordinates in uniform translatory motion.
2. Any ray of light moves in the “stationary” system of co-ordinates with
the determined velocity c, whether the ray be emitted by a stationary or by a
moving body
. Hence
velocity = light path/
time interval.
Two postulates. Note what he said:"where time interval is to be taken in the sense of the definition in § 1."
Time should be taken by the definition of simultaneous considerations.
note this chapter explain why two clocks are not synchronous.i.e it shows clocks on stationary observer and clocks of moving observer relative to stationary system do not go at the same rate.
His words:
We imagine further that with each clock there is a moving observer, and
that these observers apply to both clocks the criterion established in § 1 for the
synchronization of two clocks. Let a ray of light depart from A at the time4
tA,let it be reflected at B at the time tB, and reach A again at the time t
0
A. Taking
into consideration the principle of the constancy of the velocity of light we find
that
tB − tA =
rAB/
c − v
and t
0
A − tB =
rAB/
c + v
where rAB denotes the length of the moving rod—measured in the stationary
system. Observers moving with the moving rod would thus find that the two
clocks were not synchronous, while observers in the stationary system would
declare the clocks to be synchronous.
So we see that we cannot attach any absolute signification to the concept of
simultaneity, but that two events which, viewed from a system of co-ordinates,
are simultaneous, can no longer be looked upon as simultaneous events when
envisaged from a system which is in motion relatively to that system.
See this he used simultaneous consideration to Two clocks don't go at the same rate.(You know what i mean)
