# How do we know time flows?

validity

Thu 30 Apr, 2009 06:58 pm
@xris,
[quote=xris]I don't think your demonstration helps you, it helps me.[/quote]I think that depends on the interpretation of the demonstration.

[quote=xris]When the ball impacts on the stationary ball does a ball stop?.[/quote] The stationary ball does not move so it can not be said it stops i.e. it was not moving to begin with, but it does act in the transfer of momentum from both groups of balls that are travelling in the left and right direction. If any of the moving balls were to stop, they have lost all the momentum they have. No, none of the moving balls stop during the collisions, until all momentum has been converted into heat, sound, resisting gravity etc and in which case they all stop.

[quote=xris]If you have one stationary and one moving the one that stops obviously stops and one was stopped already.Both had no motion but one maximum potential.A bit like the pendulum at its point of turn.The fly had stopped like the train but the train had all the potential.?.[/quote] Keeping with "both moving in opposite directions" the fly and train are not rigid, they can compress, and total momentum transfer is not instant, it moves like a shockwave. At first contact a small portion of the fly momentum is transferred to the train and vice versa. That which is involved in this react accordingly eg the fly's head begins to move in the direction of the train. Is it this point that you mean the fly stops i.e. the first instance where the first fly molecules begin to change direction? If it is then from interpretation above there is still plenty of train momentum available to cause further change i.e. part of the fly stops but the total train momentum has not been depleted. At some time in the overall process the fly's abdomen is not even "aware" that the fly's head is now moving in the opposite direction to it.

[quote=xris]If you look at a river the water is moving down river by the action of gravity, it flows. The activity that gives us time is not moving its changing.Time itself is not going somewhere it is just happening,this occurrence is now it wont happen again or further ahead in time.?[/quote] I think we agree on the change and time relation and in the example of fly and train the activity that is changing is non-instant momentum transfer.

xris

Fri 1 May, 2009 03:26 am
@validity,
Sorry but we must agree to disagree.The initial action is one ball is moving and one is stopped.On impact one ball stops and transfers its momentum to the other and it moves.With this in mind the ball that was initially moving has to stop because of the stationary ball.I dont understand you interpretation at all , for me its not logical.Sorry Xris.

validity

Fri 1 May, 2009 03:25 pm
@xris,
xris wrote:
Sorry but we must agree to disagree.The initial action is one ball is moving and one is stopped.On impact one ball stops and transfers its momentum to the other and it moves.With this in mind the ball that was initially moving has to stop because of the stationary ball.I dont understand you interpretation at all , for me its not logical.Sorry Xris.
If we were talking about a Newton cradle with one stationary ball and one moving ball, I would partially agree with you. But I have not been discussing such a thing

[quote=xris]It reminds me of the question can a fly stop an express train.Initially one thinks not but when you consider that the fly travelling towards the train before it can be turned around by the impact it has to stop,so if the fly stops the train has stopped.Is time flowing does a river flow? When you look closely it only begs the question , what is flowing what does it actually mean? If its looked at this closely nothing flows.[/quote] Both objects initially moving. [quote=xris]So does the fly stop or not?If it does not stop how does it change direction without stopping..I still claim its not if it stops, its for how long..The law of logic demands it stops..[/quote] Both objects initially moving.[quote=xris]If one had more mass than the other and more speed it would overcome the lighter and slower train and push it backwards.Before it pushed it backwards they would both stop, for considerable longer than when my train hit the fly but stop they do.Xris..[/quote] Both objects initially moving. [quote=xris]I will up the anti..two trains equal speed equal weight.They collide head on,logic will tell us they both stop ,agree?[/quote] Both objects initially moving.

My post with link to demonstration made mention [quote=validity]demonstrated here at 34 seconds.[/quote] At 34 seconds both objects initially moving

An instance where the conditions of the discussion made a change [quote=xris]I don't think your demonstration helps you, it helps me.When the ball impacts on the stationary ball does a ball stop?[/quote] was corrected in the interest of discussion[quote=validity] Keeping with "both moving in opposite directions"[/quote]

Perhaps my discussion is not logical only because of what it is you think it is I am discussing, which I have done my best to show you that I have not been discussing what it is you think I am discussing.

Post you later

Alan McDougall

Fri 1 May, 2009 04:44 pm
@YumClock,
YumClock wrote:
I think this is a wonderfully logical post.
I simply cannot imagine a smallest increment, though.
Assuming the Planck length is indeed the smallest, I don't see why you couldn't hold it up and cut it in half. In a literal sense, there may be nothing small enough to cut it, but mentally it could be done.
The same goes with the unit of time you mentioned.

I know that I'm wrong, by the way, in thinking this. Can anyone convince me otherwise?

Who knows maybe times jumps in infinitesimal short frames much like a movie reel, or it both flows in waves much a fundamental particle and it just depends on the observer, which mode of time they observing

Without an observer would time be considered to still flow?

xris

Sat 2 May, 2009 03:26 am
@Alan McDougall,
Alan McDougall wrote:
Who knows maybe times jumps in infinitesimal short frames much like a movie reel, or it both flows in waves much a fundamental particle and it just depends on the observer, which mode of time they observing

Without an observer would time be considered to still flow?
Exactly what i am trying to convey with my fly and train Alan.It becomes the true philosophical scientific conundrum.An instance in time can not be divided or added to , it is only ever that instant.The instant that fly made contact with that train we saw a moment frozen in that instant.We accept a photo as a record of that moment but not the reality it poses for us.Because time is not static we cant imagine time as being anything other than a constant flow.It is a moment of activity.

Alan McDougall

Sat 2 May, 2009 10:00 am
@xris,
xris wrote:
Exactly what i am trying to convey with my fly and train Alan.It becomes the true philosophical scientific conundrum.An instance in time can not be divided or added to , it is only ever that instant.The instant that fly made contact with that train we saw a moment frozen in that instant.We accept a photo as a record of that moment but not the reality it poses for us.Because time is not static we cant imagine time as being anything other than a constant flow.It is a moment of activity.

I see what you mean xris example we state at 12 o'clock we will do this or that. But 12 o'clock never really happens, we look at the clock, it does not stop at 12 o clock, it just flows passed it.

Do we ever reach a moment in time?

If this is what you are suggesting , I agree completely

xris

Sat 2 May, 2009 11:59 am
@Alan McDougall,
Alan McDougall wrote:
I see what you mean xris example we state at 12 o'clock we will do this or that. But 12 o'clock never really happens, we look at the clock, it does not stop at 12 o clock, it just flows passed it.

Do we ever reach a moment in time?

If this is what you are suggesting , I agree completely
I wish it was so i could go to bed content but its not.Tap on the table and imagine those taps as moments in time.Time is like the clock ticking away parts of an inseparable motion of events.cause upon event after cause.

Alan McDougall

Sat 2 May, 2009 12:33 pm
@xris,
xris wrote:
I wish it was so i could go to bed content but its not.Tap on the table and imagine those taps as moments in time.Time is like the clock ticking away parts of an inseparable motion of events.cause upon event after cause.

We could also use the example of an arrow in flight. It needs time to get from the bow to the target

It is perplexing the arrow never stops in its flight and seems to flow with time

There is a start as its leaves the bow and an end when it reaches its target

Energy of the bow string imparted into the arrow during its flight to the target and energy dissipation as it reaches its target

Here we have speed , time, energy and entropy as all applying to the arrow during its journey to its target

Gosh! I make something simple complex, but that is physics

ACWaller

Sat 2 May, 2009 12:46 pm
@etcetcetc00,
In a way, time is the one thing that neither flows (i.e. changes with respect to time) nor is static (stays the same with repect to time). Matter flows, energy flows. Time is just time.

xris

Sat 2 May, 2009 01:02 pm
@ACWaller,
Just try convincing others, thats what you believe..ive tried..oh ive tried..

Alan McDougall

Sun 3 May, 2009 12:33 am
@ACWaller,
ACWaller wrote:
In a way, time is the one thing that neither flows (i.e. changes with respect to time) nor is static (stays the same with repect to time). Matter flows, energy flows. Time is just time.

Then please explain what time really is for the rest of us still debating what it is?

Why cant time also flow? :perplexed:

Is it just something we humans invented to measure how long its takes for objects around us to move?