studiot

Would Montezuma have recognised flashes from a heliograph as a signal? And what would he have made of signals from a Napoleonic semaphore?

I don't see anything remotely offensive in post#4. Surely if someone doesn't like the subject the simple answer is not to visit the thread?

Actually it is, but it is only an analogy to help explain where probabilities fit into QM. If you take the one dimensional Schrodinger equation the particle must be somewhere along the single axis you have. But that axis is homeomorphic to a segment of itself so it is legitimate to use a finite interval to represent the full line. The process of normalisation maps the whole line to the interval (0.1). Are you not thinking of boundary conditions here? Whole number waves have no meaning on an infinite line.

You can improve the model by noting that the ball must be somewhere so the total probability of it being on the channel equals one. Further if the channel is tilted down the ball will accelerate so the speed of the ball will increase as it rolls down and therefore the probability of hitting it will decrease. Alternatively the channel may be tilted upwards so the ball will slow. The model, of course is to compare the probability of hitting the ball with the probability of finding the electron in a given segment of space. You can even extend the model to probabilities curves that rise and fall with a hump, like an electron orbital.

Probabilities are just a very useful interpretation of the square of the wavefunction. There are other interpretations. It's similar to the following: Suppose your friend rolls a baseball along a channel from one end to the other, Now suppose that at some time t after he has set the ball in motion you whack down with a baseball bat. You can calculate a probability that you will hit the ball, which decreases with the speed of the ball and increases with the time your bat spends down on the channel. Wave function probabilities are like that, for a given segment of space.

Thank you for a better viewpoint JC, your numbers certainly stack up. I didn't think of that explanation, but it's so obvious when you put it like that, and really helps the thread along.

Thank you Sensei, yes I know it was programmed to not do what it was instructed. Would you expect your children to think they know better and not do what they were told?

The label states the standard dose. Your maths is adrift. 0.025% [math] = \frac{{.025}}{{100}}g/L[/math] [math] = .00025g/L[/math] [math] = 0.250mg/L[/math] [math] = 250\mu g/L[/math] If you want to know why the 0.025% and 0.035%, fumaric acid is diprotic and the salt is some mixture of ketotifen hydrogen fumarate and ketotifen fumarate that makes 250 microgrms of it equivalent to 350 micrograms of pure fumarate. You will need to ask pharmacist for more details than that.

According to the BNF (British National Formulary) the standard dose for eye drops is 250 microgrms per mL = 0.25 milligrams per mL

I note that the OP is a geoinformatics engineer and is perhaps looking for more of an operational view. I am guessing that some satellite is gathering data using one of these techniques. Anyway it is good that several interpretations are available. There are also techniques known as resonance fluorescence and resonance Raman spectroscopy. Indeed here is a quote from Whiffen : spectroscopy Edit Why are computers so stupid? On the posting entry editor I can write a c in parenthesis, and see it that way there on the editing editor afterwards. Yet it appears in my full screen as the copyright symbol. I make more than enough genuine spelling mistakes, without the system inventing them.

Because I am not drawing Feynman diagrams How is that caustic comment helpful to the thread?

A simpler answer than swansont's is that flourescence is a light emission and Ramam scattering is the result of light subtraction (absorbtion). With flourescence some of the incident light is first absorbed by the substance. But what is left of the incident beam is simply reduced in intensity, its frequency/wavelength is unchanged. That is the individual photon's energy remains unchanged, there are just fewer of them left in the incident beam. Each absorbed photon is fully absorbed. Additionally other light is now observed, at particular frequencies, different from those of the incident light. This additional light is due to the absorbed light being re-emitted, almost instantaneously and is called the flourescence. These are new photons due to the emission. With Raman scattering some of the incident light is again absorbed but in a different manner so that the photons actually loose some energy, but none are fully absorbed. So this time the intensity remains the same (ie number of photons) but they have lost some energy so have lower frequency/longer wavelength. Further they are partly deflected in direction hence so the beam is broadened or scattered. None of the observed photons are new photons as with flourescence.

Well from what I can see, you gave fuzzwood the correct formulae for energy, but you are having trouble understanding acceleration. For this reason you should complete (1) first since it is easier, and properly answer my three questions about it. As regards question (2) Do you think this is an energy question? Do you know the formulae (equations of motion) for a body with zero acceleration and constant acceleration?

In physics (and other sciences) every word is important and means something or it would not be there. I'm sorry you have to translate from your native Romanian to English but we must try. So we cannot guess the problem you must tell us all of it.

One step at a time. You say the 1kg mass is travelling vertically upward at a speed of 10m/s. So is it accelerating or decelerating or is the speed constant? Please tell me why (or why not) in each instance.

You are asked about a single state and is for a change from one state to another. The only available change is from/to solid and liquid and for an equilibrium state Gsolid = Gliquid so =0 always. The diagram I drew is followed by most substances, and results in my truth table. It is true that water is anomalous and line B leans back for water so your Tsystem may be < Tt ; thus making D may be correct for water. However it still goes upwards (on the P axis) from Tt so Psystem > Pt always, even for water. But you were asked which was always correct and D is only correct sometimes, but incorrect most times. It was nice to see someone thinking about it.

So what have you achieved so far, and have you read the rules of homework help? http://www.scienceforums.net/topic/75772-read-this-before-posting-in-homework-help/ Don't forget to convert temperatures to absolute before doing any calculations.

Since you have the answer and seek deeper explanation for it I think offer a fuller discussion than would be allowed initially for homework. The question discusses G so I am guessing this is a Chemistry question. Chemists and physicists use P as the vertical axis and T as the horizontal axis in a PT diagram, unlike engineers who tend to do it the other way round. You say that you are interested in nanotechnology so I assume that includes computing and have constructed a truth table. Now the question is about understanding two things and has presented two statements about the state of the system. This is because it is about two separate things, the phase rules and the general form of a PT diagram. Firstly the phase rule, from which we can deduce that for equilibrium across a phase boundary G1=G2 ; P1=P2 ; T1=T2 where 1 and 2 refer to the phases. The equilibrium is important because even if the question did not explicitly state this you need to assume this and not that the system point is just passing through the liquid/solid phase line. If it is just passing through and not in equilibrium we cannot apply most of the equations and cannot even determine the 'state' of the system. OK so the system state is in equilibrium on the solid liquid phase boundary. You say you understand why [math]\Delta G = 0[/math] so making the [math]\Delta G[/math] statement in A, C and D true. Do you also understand why the [math]\Delta G \ne 0[/math] statements in B and E are false? The second statement made in the question concerns the systems state pressure/temperature relative to the triple point pressure/temperature. I have drawn a PT general diagram but this is where you need to do some work, to become familiar with the characteristics of these diagrams. The triple point is marked TRP on my diagram but I have not identified the lines, although I have divided the diagram into regions where the pressure/temperature is greater or less than the triple point temperature/pressure. Can you identify the solid. liquid and gas regions on the diagram. As a result on which line does the system state position lie A, B or C? Once you have the answers to the above you should be able to check off all the truth/falsity values in the last column of my truth table. You answer is then the only one with True in both columns.

Hello colemanwk, and welcome. Ophiolite has given good advice, +1, you should be able to discuss this with your professor, I'm sure he will be happy to expand on his title. Yes I agree that the English is unclear for a number of reasons. But then you have not told us the context of the Question. That is in what subject, module or course is it set? This is very important because of the wording. Firstly you have stated methods in the plural. So I wonder if this is about the so called scientific method, or even any particular method since the meat of the question is about the impact not necessarily the method itself. So for instance if this essay is for social history or ethics what about the ethics of the scientific methods employed by tha Nazis or Stalinist Russia? Or perhaps you wish to go much further back in history. The ancient Greeks were great scientists, but poor technologists and never built arches or great aqueducts for instance. By contrast the Romans were poor scientists but great technologists, who applied the scientific knowledge of the Greeks. Or perhaps you could discuss the change from religous based 'science' to observation based science in the renaissance. Names like Galileo and Copernicus come to mind. One final thougt, Cambridge University pioneered the term 'Natural Sciences' by which they mean the physical sciences. https://www.google.co.uk/search?hl=en-GB&source=hp&q=cambridge+natural+science+tripos&gbv=2&oq=cambridge+natural+science+tripos&gs_l=heirloom-hp.3..0j0i22i30l4.5109.18844.0.19344.32.19.0.13.13.0.219.2498.1j16j2.19.0....0...1ac.1.34.heirloom-hp..0.32.2981.tJ79Z5X69Dg So you should clarify this with your professor. He may mean what is termed the 'life sciences'.

Thank you phi for all, I was hoping a moderator would intervene. +1 (post315)

No, If I had meant you I would have said so, although some of your remarks do not suggest even handedness to me. Are you suggesting that iNow did not put up post#281 or that he has no responsibility for its content or if neither, what are you suggesting?

How much maths do you know? OK so add 0.024 x 109 cubic kilometers to 1.33 x 109 cubic kilometers and rework the figures. How much difference does that make?

I have no idea who or what Randall Munroe might be. I had understood that posters should not ask others to read links except as further information and that they posters should verify for themselves the worth of any link they offered. I further thought posters should refrain form personalising and adding emotively loaded sarcastic comments to their statements, which might otherwise be truthful. As regards to your comment on the thermal expansion of water I have presented my calculations for all to see.

I don't usually award minus points but I did so this time for deleting something offensive after I had answered and referenced it in my post#303. Have you done any calculations on your supporting links to test their veracity, I am currently looking at the expansion aspect. Do you have any data for how deep the expected temperature rise would penetrate in 200 years and does that data discuss where the energy would come from to raise the water temperature nearly 10 degrees centigrade and how long it would take to perform this feat in a kettle the size of the world ocean? Edit : OK so here are some more calculations Taking the figure of 1.33x109 cubic kilometres of water from post#282 and the coefficient of cubical expansion of water, which can be found in any decent book of engineering tables as 0.000214 or here http://www.engineeringtoolbox.com/volumetric-temperature-expansion-d_315.html I calculate as follows For a rise of the whole ocean of 10 degress centrigrade the expansion is 1.33 x 109 x 0.000214 x 10 = 2.85 x 106 cubic kilometers. This figure is about 10% of the volume of ice available (again detailed in post#282) at 24 x 106 cubic kilometers. This does not agree with your statement in post #302

Do you not agree that figures should be accurate or that sources should be checked for veracity before being presented as fact?