### A rigid rod with 8 clocks

 1 Nicolaas Vroom A rigid rod with 8 clocks Friday 8 November 2019 2 Dono, Re :A rigid rod with 8 clocks Friday 8 November 2019 3 tjrob137 Re :A rigid rod with 8 clocks Friday 8 November 2019 4 Jose Gonzalez Re :A rigid rod with 8 clocks Friday 8 November 2019 5 Nicolaas Vroom Re :A rigid rod with 8 clocks Friday 8 November 2019 6 Nicolaas Vroom Re :A rigid rod with 8 clocks Saturday 9 November 2019 7 Nicolaas Vroom Re :A rigid rod with 8 clocks Saturday 9 November 2019 8 Thomas 'PointedEars' Lahn Re :A rigid rod with 8 clocks Saturday 9 November 2019 9 Nicolaas Vroom Re :A rigid rod with 8 clocks Saturday 9 November 2019 10 tjrob137 Re :A rigid rod with 8 clocks Saturday 9 November 2019 11 Thomas 'PointedEars' Lahn Re :A rigid rod with 8 clocks Saturday 9 November 2019 12 Re :A rigid rod with 8 clocks Saturday 9 November 2019 13 tjrob137 Re :A rigid rod with 8 clocks Saturday 9 November 2019 14 Nicolaas Vroom Re :A rigid rod with 8 clocks Sunday 10 November 2019 15 Jose Gonzalez Re :A rigid rod with 8 clocks Sunday 10 November 2019 16 tjrob137 Re :A rigid rod with 8 clocks Monday 11 November 2019 17 Thomas 'PointedEars' Lahn Re :A rigid rod with 8 clocks Wednesday 13 November 2019 18 Nicolaas Vroom Re :A rigid rod with 8 clocks Wednesday 13 November 2019 19 Nicolaas Vroom Re :A rigid rod with 8 clocks Wednesday 13 November 2019

A rigid rod with 8 clocks.
19 posts by 7 authors

### 1 A rigid rod with 8 clocks

From: Nicolaas Vroom
Datum: Friday 8 November 2019
Consider a rod with 8 clocks, equally spaced, a distance l apart. The rod is considered at rest. This implies that the speed of light c in all directions is the same. We call this rule 1.
The clocks are numbered from #1 to #8. The strategy is to perform a certain number of experiments.

The first experiment is called clock synchronisation.
Halfway in between clock #4 and #5, there is a light source which emits a reset signal. The setup is such that the length lightpath to each clock is the same. Using rule 1 the light signal will reach all the clocks simultaneous. This is important because all the clocks at any moment will all show the same count.

The second experiment starts with making an exact copy of rod #1. Also attached to each clock there is an engine which can be fired with a standard burst in either the forward or backward direction. Each clock also has an observer.
The second experiment consists that each observer on rod #2 fires his engine with a standard burst in the same direction when his clock is reset. This burst will give the rod a certain speed v.
The now moving observers will perform the next tasks when they reach the next clock at rest: They will write down the reading of the clock at rest and the reading of their own moving clock.
This is the result:
They are the same for all observers. The number of counts of the moving clocks is less than the number of counts of the clocks at rest. This is not so strange because it means that the physical forces which influence the behaviour of each clock are identical. Specific what this means is that all the moving clocks stay synchronised. This is rule 2. You can repeat this experiment, but still, rule 2 applies.

Experiment 3 is almost identical to experiment 2. That means all the engines are fired after the reset signal is received. This defines the starting condition of experiment 3. The starting condition of experiment 3 is a moving rod with the speed v. Experiment 3 involves that a certain moment the light signal between clock #4 and #5 of the moving rod issues a reset signal. Like before the moving observers write down the results when they reach the next clock at rest. This is the result:
All the observers write down the same number of counts for the clocks at rest. For the moving clocks, the results are different. The clock in front will have the lowest count. The clock at the back the highest count. Physical the clock in the back is reset the first.

Experiment 4 is the same as Experiment 3 with the difference that we again make an exact copy of rod #2 before the reset signal is issued. This is rod #3. The extra complication is that in experiment 4 both the moving rod #2 and #3 receive the same reset signal. The next complication is that when each of the clocks of rod #3 receives a reset signal also the engine is fired in the same direction as experiment #2. However, this will also give a physical complication, because the engine in the back will start first and in front of the latest. As such the physical forces will try to compress the rod. The opposite case is also possible. That means physical forces will try to expand the length of the physical rod.

Experiment 2 belongs to what you can call a symmetrical experiment. This is the case if you start from a state at rest than in either direction the results are the same i.e. how higher the speed how slower the moving clock ticks.
What is also the case, after reaching a certain speed and the speed is decreased the clock starts to run faster until the speed reaches zero.

Experiment 4 belongs to what you can call an asymmetrical experiment. This is the case when the starting condition involves a moving rod. In that case, when a clock receives a burst in the same direction as the original speed the clock will start to run slower. In the opposite direction, it is first faster and then slower.

These results are maybe different as what is expected. They challenge the concept of what means at rest.

Nicolaas Vroom

### 2 A rigid rod with 8 clocks

From: Dono,
Datum: Friday 8 November 2019
The Nicholas Vroom imbecile is back! On Friday, November 8, 2019 at 7:35:19 AM UTC-8, Nicolaas Vroom wrote:
 > snip new imbecilities from old idiot< Nicolaas Vroom
Have you considered joining forces with David Seppala? You two would make a great team.

### 3 A rigid rod with 8 clocks

From: tjrob137
Datum: Friday 8 November 2019
On 11/8/19 9:35 AM, Nicolaas Vroom wrote:
 > Consider a rod with 8 clocks, equally spaced, a distance l apart. [...] Halfway in between clock #4 and #5, there is a light source which emits a reset signal. The setup is such that the length lightpath to each clock is the same.

These are inconsistent. Everything following is useless.

Tom Roberts

### 4 A rigid rod with 8 clocks

From: Jose Gonzalez
Datum: Friday 8 November 2019
Nicolaas Vroom wrote:

 > Consider a rod with 8 clocks, equally spaced, a distance l apart. The rod is considered at rest. This implies that the speed of light c in all directions is the same. We call this rule 1.

What would it be otherwise? And 8 clocks, come on, you can find a better excuse in your defence. Jose Gonzalez

### 5 A rigid rod with 8 clocks

From: Nicolaas Vroom
Datum: Friday 8 November 2019
Nicolaas Vroom wrote:

 > The first experiment is called clock synchronisation. Halfway in between clock #4 and #5, there is a light source which emits a reset signal. The setup is such that the length lightpath to each clock is the same. Using rule 1 the light signal will reach all the clocks simultaneous. This is important because all the clocks at any moment will all show the same count.

You may put the clocks all you want, but will never affect the speed of light and anything. Clocks are not related to light in anyway.

### 6 A rigid rod with 8 clocks

From: Nicolaas Vroom
Datum: Saturday 9 November 2019
I do not see any inconsistency in the text. How do you synchronize two clocks #1 and #2? You place a light source halfway between these two clock at x12 and issue a reset signal in both directions towards #1 and #2.

How do you synchronize four clocks #1, #2, #3 and #4 (in a straight line)? You place a light source halfway between the two clock #2 and #3 at x23. and issue a reset signal in both directions towards two beam splitters at x12 (halfway between the clocks #1 and #2) and at x34 (halfway between the clocks #3 and #4). The rest is the same as above. This same strategy can also be used for eight clocks.

For more information about clock synchronization study the book "SpaceTime physics"by E.F. Taylor and J.A.Wheeler, second edition. Specific the pages:37 and 38

Nicolaas Vroom

### 7 A rigid rod with 8 clocks

From: Nicolaas Vroom
Datum: Saturday 9 November 2019
On Friday, 8 November 2019 23:18:43 UTC+1, Jose Gonzalez wrote:
 > Nicolaas Vroom wrote:
 > > The first experiment is called clock synchronisation. This is important because all the clocks at any moment will all show the same count.
 > You may put the clocks all you want, but will never affect the speed of light and anything. Clocks are not related to light in any way.

The starting point of clock synchronization is that all the clocks are at rest and that the speed of light is the same in all directions.
In noway the speed of light is affected.
The clocks involved use light signals. See for example page 12 of the book: "SpaceTime physics" by E.F. Taylor and J.A.Wheeler, second edition. The whole issue is that all clocks at rest behave the same.

A different issue is that clocks which move relative to these clocks at rest behave (physical) differently. They count slower.

Nicolaas Vroom.

### 8 A rigid rod with 8 clocks

From: Thomas 'PointedEars' Lahn
Datum: Saturday 9 November 2019
I think that he means that the “length lightpath” to each of the clocks #4 and #5 is the same. Would you still see an inconsistency then? If yes, which?

-- PointedEars FAQ: http://PointedEars.de/faq>> | https://github.com/PointedEars>> | Twitter: @PointedEars2 | Please do not cc me./Bitte keine Kopien per E-Mail.

### 9 A rigid rod with 8 clocks

From: Nicolaas Vroom
Datum: Saturday 9 November 2019
Rods are not rigid ...... full stop

### 10 A rigid rod with 8 clocks

From: tjrob137
Datum: Saturday 9 November 2019
On 11/9/19 6:13 AM, Nicolaas Vroom wrote:
 > On Friday, 8 November 2019 22:55:53 UTC+1, tjrob137 wrote:
 >> On 11/8/19 9:35 AM, Nicolaas Vroom wrote:
 >>> Halfway in between clock #4 and #5, there is a light source which emits a reset signal. The setup is such that the length lightpath to each clock is the same.
 >> These are inconsistent. Everything following is useless.
 > I do not see any inconsistency in the text.

It simply is not possible for eight clocks to be equally spaced along the rod, and yet the light paths from the center of the rod to each of them are all equal. Clock #8 is OBVIOUSLY further away than clock #4, etc.

Hint: light travels in straight lines; rods are also straight.
You could, for instance, specify equal-length optical fibers from the light source to each of the clocks. But you must SAY that is what you are doing.

 > [...]

When you change the physical description like that, then everything is changed. Changing in the middle of a discussion just confuses everybody, INCLUDING YOURSELF -- the thread splits with different people following different descriptions, and becomes impossible to follow.

Also: I ignore excessively complicated scenarios. Figure out what is the essence of what you are trying to discuss, and construct a simpler scenario involving just it.

Tom Roberts

### 11 A rigid rod with 8 clocks

From: Thomas 'PointedEars' Lahn
Datum: Saturday 9 November 2019
Tom Roberts wrote:

 > On 11/9/19 6:13 AM, Nicolaas Vroom wrote:
 >> On Friday, 8 November 2019 22:55:53 UTC+1, tjrob137 wrote:
 >>> On 11/8/19 9:35 AM, Nicolaas Vroom wrote:
 >>>> Halfway in between clock #4 and #5, there is a light source which emits a reset signal. The setup is such that the length lightpath to each clock is the same.
 >>> These are inconsistent. Everything following is useless.
 >> I do not see any inconsistency in the text.
 > It simply is not possible for eight clocks to be equally spaced along the rod, and yet the light paths from the center of the rod to each of them are all equal. Clock #8 is OBVIOUSLY further away than clock #4, etc.

Your argument rests on your assumption that this was meant. AFAICS, it is a straw man argument. Jose Gonzalez

### 12 A rigid rod with 8 clocks

From:
Datum: Saturday 9 November 2019
Thomas 'PointedEars' Lahn wrote:

 > Tom Roberts wrote:
 >> On 11/9/19 6:13 AM, Nicolaas Vroom wrote:
 >>> On Friday, 8 November 2019 22:55:53 UTC+1, tjrob137 wrote:
 >>>> On 11/8/19 9:35 AM, Nicolaas Vroom wrote:
 >>>>> Halfway in between clock #4 and #5, there is a light source which emits a reset signal. The setup is such that the length lightpath to each clock is the same.
 >>>> These are inconsistent. Everything following is useless.
 >>> I do not see any inconsistency in the text.
 >> It simply is not possible for eight clocks to be equally spaced along the rod, and yet the light paths from the center of the rod to each of them are all equal. Clock #8 is OBVIOUSLY further away than clock #4, etc.
 > Lbhe nethzrag erfgf ba lbhe nffhzcgvba gung guvf jnf zrnag. NSNVPF, vg vf n fgenj zna nethzrag.

You have no tensors to prove any of it. Shut up and repent.

### 13 A rigid rod with 8 clocks

From: tjrob137
Datum: Saturday 9 November 2019
On 11/9/19 12:54 PM, Thomas 'PointedEars' Lahn wrote:
 > Tom Roberts wrote:
 >> On 11/9/19 6:13 AM, Nicolaas Vroom wrote:
 >>> On Friday, 8 November 2019 22:55:53 UTC+1, tjrob137 wrote:
 >>>> On 11/8/19 9:35 AM, Nicolaas Vroom wrote:
 >>>>> Halfway in between clock #4 and #5, there is a light source which emits a reset signal. The setup is such that the length lightpath to each clock is the same.
 >>>> These are inconsistent. Everything following is useless.
 >>> I do not see any inconsistency in the text.
 >> It simply is not possible for eight clocks to be equally spaced along the rod, and yet the light paths from the center of the rod to each of them are all equal. Clock #8 is OBVIOUSLY further away than clock #4, etc.
 > Your argument rests on your assumption that this was meant. AFAICS, it is a straw man argument.

No, my argument rests on the original description of the physical situation:
"a rod with 8 clocks, equally spaced, a distance l apart" "numbered from #1 to #8."
and
"Halfway in between clock #4 and #5, there is a light source which emits a reset signal. The setup is such that the length lightpath to each clock is the same."

I challenge you to display a physical arrangement that meets both specifications, without invoking magic.

[Vroom later said that he intended to invoke a bunch of beamsplitters, or a bunch of sources, essentially invoking magic.]
Tom Roberts

### 14 A rigid rod with 8 clocks

From: Nicolaas Vroom
Datum: Sunday 10 November 2019
- show quoted text - Before accusing me of all sorts of funny actions, I please ask the readers to do as I asked before:

https://www.nicvroom.be/Article_Review_Moving%20Bodies_Appendix2.htm
 > specific picture 1. (*)

What Picture 1 shows you can also observe using this link: https://www.nicvroom.be/Moving_clocks_Reset_v=0_v2=0.3.jpg

As a courtesy to you, I will copy the text near that picture.

Quote Picture 1 on the left shows Clock Synchronisation for 8 clocks, identified with the numbers #1 until #8. The horizontal axis shows the x-axis. The vertical axis shows the time-axis
1. The point R0 contains the reset source (halfway between the clocks #4 and #5) This is the position of the clock tested. From this point, two reset signals are issued in the +x and -x direction towards the points R1. These signals are drawn under an angle of 45 degrees.
2. The two points R1 are beam splitters. They are in some sense completely identical as R0. From each of these points, two reset signals are drawn in the +x and -x direction.
3. The four points R2 are beam splitters. They are in some sense completely identical as R0 and R1. From each of these points, two reset signals are drawn in the +x and -x direction towards the 8 clocks.
4. When the reset signals reach the clocks #1 to #8, they are reset. Because the path length is the same, they run simultaneously.
End of quote.

Above picture 1 there is also important text to read:
Quote
The second reset point in between points #6 and #7 is used also to create two new reset points: one between points #5 and #6 and one between the points #7 and #8.
Each of these 4 reset points is used to reset the two nearby clocks. Total light distance = 2l+1l+0.5l = 3.5l
End of quote.

(*) This link is part of the Article Review "On the Electrodynamics of moving Bodies - by A. Einstein 1905 - Article review". To read the article review select:
https://www.nicvroom.be/Article_Review_On%20The%20Electrodynamics%20Of%20Moving%20Bodies.htm

Nicolaas Vroom

### 15 A rigid rod with 8 clocks

From: Jose Gonzalez
Datum: Sunday 10 November 2019
I'm not sure. Eight clocks implies only seven equidistant distances. You need to find out about the 8th distance, in order for your little lemma to work.

### 16 A rigid rod with 8 clocks

From: tjrob137
Datum: Monday 11 November 2019
On 11/8/19 9:35 AM, Nicolaas Vroom wrote:
 > Consider a rod with 8 clocks, equally spaced, a distance l apart. The rod is considered at rest. This implies that the speed of light c in all directions is the same. We call this rule 1. The clocks are numbered from #1 to #8. The strategy is to perform a certain number of experiments.

Let me call this initial inertial frame K.

 > The first experiment is called clock synchronisation. Halfway in between clock #4 and #5, there is a light source which emits a reset signal. The setup is such that the length lightpath to each clock is the same.

As you subsequently explained, there are additional components involved to make the light paths equal.

It is important to describe the physical situation completely.

 > Using rule 1 the light signal will reach all the clocks simultaneous. This is important because all the clocks at any moment will all show the same count.

By "any moment" you mean "observed simultaneously in K, by observers co-located with each clock".

It is important to describe things precisely.

 > The second experiment starts with making an exact copy of rod #1.

Presumably all of its clocks are synchronized in K, and with all the clocks of the original rod.

It is important to describe things completely.

 > Also attached to each clock there is an engine which can be fired with a standard burst in either the forward or backward direction. Each clock also has an observer. The second experiment consists that each observer on rod #2 fires his engine with a standard burst in the same direction when his clock is reset.

This "when" is ambiguous. I presume the observers are not clairvoyant, so each one actually fires their engine a negligibly short time after their clock receives the reset signal. So they all fire simultaneously in K.

 > This burst will give the rod a certain speed v.

Let me call this second inertial frame K', and we agree not to discuss it before or during the firing of the engines.

 > The now moving observers will perform the next tasks when they reach the next clock at rest: They will write down the reading of the clock at rest and the reading of their own moving clock.

OK. Of course the leading clock at rest in K' never meets a clock at rest in K, so ignore it.

 > This is the result: They are the same for all observers. The number of counts of the moving clocks is less than the number of counts of the clocks at rest.

Yes. The clocks at rest in K' are all synchronized in K -- NOT K'. Seven of them meet the next clock at rest in K at the same time in K, and the same time displayed on their own clocks (which is different from the time indicated by the clocks at rest in K).

Note that an observer at rest in K' would describe the clocks at rest in K as closer together than the clocks at rest in K', and none of the clocks are synchronized in K'. In terms of the coordinates of K', the clocks successively meet in pairs, but when each clock from K' meets the clock in K, all clocks in K indicate the same time, and all clocks in K' indicate the same time (that is different from those in K).

 > This is not so strange because it means that the physical forces which influence the behaviour of each clock are identical.

None of these forces influence the behavior of any clock in any way.

I assume the engines are not so powerful that they damage the clocks of the second rod.

 > Specific what this means is that all the moving clocks stay synchronised. This is rule 2. You can repeat this experiment, but still, rule 2 applies.

Your "rule 2" is VERY LIMITED, and applies to this physical situation only.

 > Experiment 3 is almost identical to experiment 2. That means all the engines are fired after the reset signal is received.

Oh. Then you assumed that the observers were indeed clairvoyant in experiment 2. So take my discussion above and apply it here.

 > This defines the starting condition of experiment 3. The starting condition of experiment 3 is a moving rod with the speed v.

This last sentence is different from what you said before, and inconsistent with the engines being fired AFTER the reset signal is received. One paragraph earlier the starting condition of experiment 3 was the same as experiment 2: both rods at rest in K.

It is important to describe things consistently.

 > Experiment 3 involves that a certain moment the light signal between clock #4 and #5 of the moving rod issues a reset signal. Like before the moving observers write down the results when they reach the next clock at rest. This is the result: All the observers write down the same number of counts for the clocks at rest. For the moving clocks, the results are different. The clock in front will have the lowest count. The clock at the back the highest count. Physical the clock in the back is reset the first.

This is wrong. See above.

 > [... too complicated to bother with.]

You MUST describe the physical situation completely AND PRECISELY AND CONSISTENTLY. Details matter, because relativity is both complicated and subtle. Whenever you say "synchronized" you must also state in which frame it applies. Whenever you say "when", you must reword to state "simultaneously in frame ...". Do not ever say "at any moment", but rather specify which frame you are using and specify values of its time coordinate. And don't assume observers are clairvoyant.

Tom Roberts

### 17 A rigid rod with 8 clocks

From: Thomas 'PointedEars' Lahn
Datum: Wednesday 13 November 2019
Sigh. [psf 10.1]

A picture says more than a thousand words:
 ``` light source : * * * * v * * * * #1 #2 #3 #4 #5 #6 #7 #8 ```
[You should have asked yourself why there are *8* clocks and why the light source is placed between clock *#4 and #5*.]

As I already indicated, this description is open to INTERPRETATION (“length lightpath” is not a word).

And for whatever reason (actually, from my own experience with you I have a fairly good idea why) you have (again) chosen THE WORST POSSIBLE INTERPRETATION, namely one leading to a setup that cannot be realized.

Honi soit qui mal y pense.

### 18 A rigid rod with 8 clocks

From: Nicolaas Vroom
Datum: Wednesday 13 November 2019
On Wednesday, 13 November 2019 01:16:34 UTC+1, Thomas 'PointedEars' Lahn wrote:
 > Tom Roberts wrote:
 > > I challenge you to display a physical arrangement that meets both specifications, without invoking magic.
 > Sigh. [psf 10.1] A picture says more than a thousand words:

 >
 ``` light source : * * * * v * * * * #1 #2 #3 #4 #5 #6 #7 #8 ```
 > [You should have asked yourself why there are *8* clocks and why the light source is placed between clock *#4 and #5*.]

You can have two clocks. Than the light source should be in between #1 and #2. You can have four clocks. Than the light source should be in between #2 and #3. In practice the number of reference clock (at rest) should be much larger than the number of moving clocks.

 > As I already indicated, this description is open to INTERPRETATION (“length lightpath” is not a word).

The whole idea behind clock synchronization, in this case, is that the length of the lightpath followed, to each clock, is the same.
Assuming that the speed of light is the same in all directions, all the reset signals will arrive simultaneous to all the clocks.

 > And for whatever reason you have chosen THE WORST POSSIBLE INTERPRETATION, namely one leading to a setup that cannot be realized.

I fully agree with you that all the type of experiments mentioned are very difficult to realize in practice. That is why I try to describe the experiments as complete, as detailed and clear as possible.

Please study the book "SpaceTime physics" by E.F. Taylor and J.A. Wheeler specific the section about clock synchronization. You can also try http://www.eftaylor.com/download.html to get a free copy of the first edition

Nicolaas Vroom

### 19 A rigid rod with 8 clocks

From: Nicolaas Vroom
Datum: Wednesday 13 November 2019
On Monday, 11 November 2019 05:44:07 UTC+1, tjrob137 wrote:
 > On 11/8/19 9:35 AM, Nicolaas Vroom wrote:

 > > Also attached to each clock there is an engine which can be fired with a standard burst in either the forward or backward direction. Each clock also has an observer. The second experiment consists that each observer on rod #2 fires his engine with a standard burst in the same direction when his clock is reset.
 > This "when" is ambiguous. I presume the observers are not clairvoyant, so each one actually fires their engine a negligibly short time after their clock receives the reset signal. So they all fire simultaneously in K.

There is nothing clairvoyant involved. Each of the moving observers uses the same script what to do and when at which specific clock count.

 > > This is the result: They are the same for all observers. The number of counts of the moving clocks is less than the number of counts of the clocks at rest.
 > Yes. The clocks at rest in K' are all synchronized in K -- NOT K'. Seven of them meet the next clock at rest in K at the same time in K, and the same time displayed on their own clocks (which is different from the time indicated by the clocks at rest in K).

Don't use the concept of time. Use clock counts.
All the moving observing observers observe the same clock count of the clocks at rest and all the observers at rest observe the same clock count of the moving clocks (assuming there is a clock)

 > In terms of the coordinates of K', the clocks successively meet in pairs, but when each clock from K' meets the clock in K, all clocks in K indicate the same time, and all clocks in K' indicate the same time (that is different from those in K).

Okay. For simplicity use counts. The issue is that the moving clocks show the lowest count compared with the clocks at rest.

 > > This is not so strange because it means that the physical forces which influence the behaviour of each clock are identical.
 > None of these forces influence the behavior of any clock in any way.

The physical forces, in this case, are the engines involved to give the clock a certain speed in either direction.

 > > Specific what this means is that all the moving clocks stay synchronised. This is rule 2. You can repeat this experiment, but still, rule 2 applies.
 > Your "rule 2" is VERY LIMITED, and applies to this physical situation only.

This rule is very powerful because it means that all the moving clocks stay synchronised if you control the engines using the same script. A specific script could, for example, be: to move from A to B and back to A.

 > > Experiment 3 is almost identical to experiment 2. That means all the engines are fired after the reset signal is received.
 > Oh. Then you assumed that the observers were indeed clairvoyant in experiment 2. So take my discussion above and apply it here.

No, they follow the same script.

 > > This defines the starting condition of experiment 3. The starting condition of experiment 3 is a moving rod with the speed v.
 > This last sentence is different from what you said before, and inconsistent with the engines being fired AFTER the reset signal is received. One paragraph earlier the starting condition of experiment 3 was the same as experiment 2: both rods at rest in K. It is important to describe things consistently.

Experiment 3 involves first Experiment 1 and thereafter Experiment 2. In total you perform the following:
2) You perform the synchronization procedure: issue a reset signal.
3) You copy all the 8 clocks (rod 2)
4) You give all the engines of rod 2 a boost at a certain clock count. (now you have a moving rod).
In this case, the next time when two observers meet (one at rest and one moving) all the readings of the clocks at rest will be the same. The clock readings of the moving clock will also all be the same.
5) Now experiment 3 starts.
You perform the synchronization procedure with rod 2: issue a reset signal in the same direction as in step 2.
6) In this case, the next time when two observers meet all the readings of the clocks at rest will be the same. The clock readings of the moving clock will all be different.

From a practical point of view rod 1 (at rest) should contain extra clocks.

 > > All the observers write down the same number of counts for the clocks at rest. For the moving clocks, the results are different. The clock in front will have the lowest count. The clock at the back the highest count. Physical the clock in the back is reset the first.
 > This is wrong. See above.

Experiment 4 is a combination of experiment 2 and 3. There are 3 rods.
1) rod 1 which involves a reset at rest.
2) rod 2: reset at rest and engine boost/moving.
3) rod 3: reset at rest, moving and again a reset.

4) rod 4: reset at rest, moving, again a reset and engine boost/moving
All this seems rather complicated, but I doubt it is.

It is important to understand that rod 1 and 2 are a pair and that rod 3 and 4 are a pair. The difference between rod 1 and rod 3 is that rod 1 is considered at rest and rod 3 is moving.
Rod 2 is a copy of rod 1 and all the engines are given the same boost (after reset)
Rod 4 is a copy of rod 3 and all the engines are given the same boost (after reset)

The problem with experiment 5 is that it will cause internal forces within the rod 4. These forces will either expand or contract the rod 4. The reason is that the engines don't fire simultaneously.

What this sequence of experiments shows that it is possible to decide by means of an experiment if a rod is at rest or moving

For more detail select: https://www.nicvroom.be/Article_Review_Moving%20Bodies_Appendix2.htm

This document also shows that there is a second experiment possible to decide if a rod is at rest or moving.

Nicolaas Vroom.

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