studiot

Both circles actually follow curtate cycloidal paths and depend upon an elliptic integral for their different path lengths. http://mathworld.wolfram.com/CurtateCycloid.html There is no paradox, but thank you for the link that leads to some interesting and entertaining videos.

Agreed, I have already mention radioactive decay of larger particles. Take a few million uranium atoms and count them count them again count them again You have the basis of a non motional clock. But many changes of state, including chemical ones, that John Cuthber should be better able to point out than I, should pass muster as an example of non motional change

The history in Wiki shows that the ideas behind the Kinetic Theory predate experimental proof by several centuries. Maybe Enthalpy's timing is a bit off, but I take his point and have already commented on Brownian motion, which can be observed directly. I would, however, support Bignose's assertion that the motion is in principle classically deterministic, not random, as claimed in the Wiki article. http://en.wikipedia.org/wiki/Kinetic_theoryI I would also like to add that I consider that the Kinetic Theory, in its various guises and developments, is one of the most important and satisfying theories in classical Physics.

@Bignose, I do believe this is a matter of first language (I don't think English is Enthalpy's) and I think Enthalpy meant accepted in the sense of "taken on trust for granted or without direct proof" not in the more obvious sense. I have made this sort of mistake before in discussions with Enthalpy; some of his statements have a deeper meaning behind them that is not obvious on first glance. There is, however, no question that your summary of the Kinetic Theory is corrrect in declaring that the mechanics of motion of the particles is entirely deterministic in principle within the laws invoked in the Kinetic Theory. If we however, consider from the point of view of a particular area or point being bombarded by these particles, the variable recording the time of bombardment takes on the mantle of a random variable, does it not?

Well personally I would not have tackled it this way, but I was concerned to make chikis method work out, rather than attempt to impose my own.

I skipped through the video and suggest that you haven't missed much.

@enthalpy. It is interesting to learn of the existence of pressure sensors sensitive enough to record the impact of a single molecule. If it is not considered off topic a link to them would be appreciated.

At least tell us why you (or the questioner) think the velocity is different at the top of the circle and 30 below the horizontal. If you think the velocity is different what is different about them?

Well I just wasted a good while preparing a diagram with comments, facts and figures, when the site froze on me.

Of course they apply. Some quantities will become zero, but that is also true of the net force on a body in equlilibrium in our normal universe under the action of many forces. In particular there can be no magnetic field, but there can be an electric one if the particle carries a charge. There will be a gravitiational field if the particle has mass and so on. Yes I agree that relativity reduces to trivia, but so what? Don't we often solve mathematical problems by transforming them into a form where some of the coefficients and/or variables become zero? Talking of mathematics, if we offer a general proposition it means that it holds for every value of our variable(s), so we are entitled to test it by using specific values to calculate the values of coefficients. This often means f(x) when x=0, f(x) when y=0 and so on. So I am doing nothig more than following a very well trod path. I chose Maxwell's equations, just because relativity reduces to trivia, but they do not completely, and because they contain the variable time, which does not vanish in a universe containing only a single particle. Or do you wish to propose that our laws of physics only hold in universes that contain a minimum number of particles and, if so, how many and by what proof?

I didn't say that you did However I am rather concerned at the apparent oscillation of the 'acidity of the ocean' with amplitude greater than the total variation over the timescale.

I'm sure chikis would be interested in your better way, if you told us what that was.

Then there is enough data to prove it statistically, without generalised hand waving. BTW I am not saying the pH is going up or down or remaining the same. I am asking for some statistical evaluation of the error in any claim. Why do people find this unreasonable for a subject linked to GW, but a requirement for any other scientific claim?

So have you got the distance between the dial gauges or the workpiece length?

But do we? There is an awful lot of ocean, compared to the size of our sampling.

What is the statistical provenance of this data?

Yes indeed it is complicated. Further considering the solubility of an atmosphere of pure carbon dioxide above pure water is very different from the solubility of the same gas in the open ocean. There is substantial discussion of the chemistry here, along with some calculations. http://www.physicsforums.com/showthread.php?t=398208

I don't understand the question here. What do you have against the kinetic theory and why does direct observation of Brownian motion not substantiate it?

I presume you (and your lecturer) know how to use a sine bar, the parts of the question you got wrong stem from the engineer's method of setting up. Slips should be added or removed until the top surface of the workpiece is parallel to the surface table. This can be done by trial and error or by the following 'quick' method. 1) Set up the bar and workpiece so the top surface is approximately parallel. 2) Take readings from the dial gauges noting the difference and which end is higher. 3) If B is lower than A add slips according to the proportion of the sine bar length to the work length. 4) IF A is lower than B remove slips according to the proportion of the sine bar length to the work length. So where A is 2mm higher than B the slips need to be increased by {2 x (200/w)}mm, to set the workpiece parallel to the table. Where w is the worklength. This gives a new slip height from which you can calculate the sine and thus the angle

You really must make sure you copy accurately from one line to the next This will make things so much easier.

Perhaps that is because they are not arguments in the reasoning sense. You are the one making the claim, not I. As such I am merely testing your chain of reasoning that leads to and supports this claim. Why do you place question marks at the end of claimed statements of fact? This is the first time you have asked for further details. Unfortunately it is founded an a fallacy. You have not shown that there is any requirement or physical law that states a condition must be observable. One of the most basic tenets of physics is that conditions are, in general and Schrodingers cat notwithstanding, the same whether they are observed or not and indeed whether or not an observer exists. That is the basis of all 'Thought experiments' and allows us to construct such experiments where conditions are contolled and specified. That is the basi of the thought experiment you have suggested. This is in direct contradiction of your post# 28 in this thread here http://www.scienceforums.net/topic/83550-what-is-time/page-2 Where I asked if you where considering just the motion of the observable or including the antics of the observer. No matter, this is a thought experiment so we can continue, by simplifying it further. Let the thought universe contain only one single particle. Now there are no observers. But the laws of Physics must still apply. And that particle experiences time according to Maxwells equations. You have not addressed my points 4 and 5 in my post#36, which contain another answer to your question.

But you are missing a lot of the (boring but essential) stuff in the middle. In the past this would have been provided on well planned syllabuses, whoever taught it. In today's world many syllabuses are poorly planned and many non core subjects only touch lightly on core material, but give the impression they cover more ground than they do.

Don't ask me, I ducked out of this one when, to paraphrase migL's words, you went from kindergarten physics to postdoc physics faster than Usain Bolt does the 100 metres.

No, please don't hit me again officer. Not another another what is time argument no please no.

1) You have again responded by changing the subject, thereby avoiding the main comment in my post (your own contradictory statements). 2) The logic of the above is completely flawed, since it rests upon a unsubstantiated statements (yes you also make them). 3) There is no absolute comparison requirement for either time or distance, or for that matter any other quantity. If there is only one of that quantity in the universe, that is perfectly within the bounds of logical acceptability. If sub division is possible then I can always create comparison by subdivision. 4) You have missed the entire point about duration. It is, in fact, linked to my earlier comment that non motional measures of time may easily be constructed by repeated observation of something that does not change. Such measurement will be outlandishly crude by swansont's standards, but hey it is still possible. 5) There are yet other ways of constructing non motional clocks, base on the statistical activity of unstable isotopes.