studiot

Whilst sourcing some components I came across this excellent downloadable pdf on constructing electonics circuits. This would be ideal for teachers of physics/electronics/instrumentation to use. https://www.mitchelectronics.co.uk/electronicsConstructionManual.pdf

Teacup ?? Spout ?? You must have been putting the wrong weed in that cigar again. Just think, without time, you'd never get to smoke it. More seriously perhaps 'you' could only perform this interaction if 'you' and the teacup were exactly like the famous hole in the ground and the puddle. Exactly spatially conformable. Otherwise if you were not then the relationship would be more like that of a point particle in a 'block universe' where the past and future are inaccessible. Your 3D space has similarities to this block universe. But this question about 'seeing' raises another interesting point. Human sight is serial in nature in that your focus scans about your field of sight. Furthermore humans can only see in front of them. If their sight was constructed differently perhaps see in front of them and behind them together - like a fly. The point is that even in computing we have serial mode and parallel mode and one other interesting one, akin to time travel. There is a method of computing whereby when the serial flow reaches a decision point, it changes to parallel flow and goes down all the branches of the decision tree together using the then existing step values of the prgram flow variables. When the appropriate new values become available the results of each side loop are already available and the correct one is selected. This is a known time saving (pun intended) device which has been used in other decision making situations, for instance We are about to be invaded. Do we set up defences on the East coast or the West coast ? No how about answering my questions about the p orbital and the jacks?

I can't begin to imagine how such a discussion arose. Geodesy is the Science of the Measurement of the Earth. Astronomy is the Science of the Measurement (nothing else) of the Heavens. Astrophysics is the Science which includes the study of stellar processes. Surely there is nothing to argue about, we just use the definitions and get on with the meat of the real issue to hand.

Just looking at your premises I find the following conclusion. Premise 2 simply proposes the existence of a fundamental Euclidian space. Premises 1,3 and 4 are redundant since they are already implied by premise 2. Premise 5 add new material but does not properly define the Field variables, which are necessary for the existence of any scalar field, since they are not one of the Euclidian axes. Premises 6 and 7 are a complete mish mash and need to be rewritten. They appear to introduce an 'observer, deny the existence of the observer and yet allocate 'properties' to this non existent observer.

As a Physicist, would you say it makes no difference if we 'observe' first the bulb then the tail or first the tail then the bulb or of a p orbital or would Physics be different if we did not experience the entire curve all together in any interaction? If you don't like a quantum example how about being struck by a large jack (as in the game of jacks) shaped object ? Do we experience the entire momentum at the moment of impact or do we have to wait for the legs to spin round and hit us?

What is also interesting is that there is more than one way to viw these relationships, which is why we have several (slightly) different terms. The condition I meant may be illustrated in the standard equation of an ellipse This is the locus of a point which moves under the one condition [math]\frac{{{x^2}}}{{{a^2}}} + \frac{{{y^2}}}{{{b^2}}} = 1[/math] Alternatively we can introduce what is known as a parameter often denoted t, though sometimes a Greek letter is used. [math]x = a\cos t[/math] [math]y = b\sin t[/math] Note the first form has two independent variables and one condition or equation, between them. The second has one independent variable (the parameter) and two conditions or equations. Both refer to the same ellipse. The parameter is often (but not always) time and corresponds to what I called the running variable. You can see how deeply time is embedded in our psyche. But in fact this parameter t is an angle!

You are describing what is mathematically called a 'locus' - The path traced out by a point moving under certain conditions. That is different from a plot of a graph.

I'm glad you got the first point, and what's more you agree with it. I also understood your very good point about the savannah / desert example. But this is a different point so I am sorry you missed my second point. Whilst it is possible that savannah and desert coexist side by side so you could make the journey from one to the other as you describe. Time would then necessarily be involved o that when you were in the desert, the savannah still existed and vice versa. It is also possible to that only one landscape exists and for a transformation from savannah to desert (or vice versa) as you pass from one area to another. In both cases a change is involved, but this is why I said a transformation is not the only form of change. However in the case of the cup, it is not possible for the bowl to transform into a handle as you look from bowl to handle. No cup can exist under such circumstances. Both handle and bowl must be present for the cup to have existance. Yet there remains a change of curvature. I also offerd a more complicated example to which you replied But you did not elaborate. If I were to further offer you some (hidden) H2O at 0o C it would be impossible for you to tell if that water was solid or liquid, or even a mixture of both, no matter how much time you has available. The answer to the question simply does not depend upon time in any way. As Marcus and I said, It must depend upon your definition. If you are going to adopt a definition based upon change then I consider I have shown examples of change that do not depend another variable than the one stated. The curvature of the object depends upon position only. The possible states of matter depend upin the temperature only for the eutictic and the cooling substance.

It's not a question of 'overcoming' , that implies all or nothing ie full transfer of an electron. The inductive effect refers to only partial transfer. Looking at you attachment, is see that the explanation is interms of electric dipole moments. I find that many Chemists are a bit hazy about dipole moments and have other ways to look at it. The other point about dipole moments is that they are vectors, which means you must add them vectorially, taking account of direction usually in 3D. So planar, linear, skeletal representations are often inadequate. So here is an alternative by considering charge redistribution or delocalisation within a molecule. (You can have the dipole version if you want it) I don't know if you have come across the curly arrow convention? It is a good idea to first understand what happens with a plain hydrocarbon carboxylic acid (acetic acid). #4 on my list shows a list of Ka the acidity equilibrium constant for acetic acid in a number of solvents, water being the most common. #1 shows the equilibrium reaction (with water). The acid anion formed is resonance stabilised as shown which leads to a stable anion and is the reason carboxyl groups are more acidic than phenols which in turn are more acidic than alcohols. Effectively the two oxygens share half the negative charge as shown in #2. I we now substitute an electron withdrawing species such as chlorine at #3 This pulls charge back from the methyl carbon, Which in turn pulls charge back from the 'carboxyl' carbon Delocalising the negative charge over the whole molecule.

Thank you for the response. It is difficult to explain further without my knowing what it is you don't see. Normally you offer a well reasoned criticism to discuss. Edit Marcus' still only refers to space (and time). But there is no reason for what I call the running variable (or either variable) in a graph to include time. Good examples of other running variables are temperature and composition. A eutectic diagram is a combination of both, neither space nor time variables get a look in. A simpler phase diagram might even make Marcus point more forcefully since 'neighbouring points' could be in different states - say solid and liquid. As I like to keep pointing out, Nature is more artful than the best straightjacket human rules can determine.

You have missed the crux of my discussion with Marcus and Michel about the teacup. Your example suggests to me that you have not picked up my point. Sorry that point is very important but also very difficult to describe/define. Since I have not succeeded in providing enough clarity I will try again. The desert, savannah etc could have separate existance, each in their own right. As you move, they could also be changed (wink into and out of existence) like a Hollywood set. So they are different from a cup which is only a cup when all the parts are present together. A handle is not a cup, a base is not a cup, a bowl is not a cup etc.

Look carefully at the structure. The carbon of the CH2 group has two competing electronegative groups attached, the chlorine and the carbonyl. The chlorine 'pulls' electrons towards itself a bit , increasing the resisiting effect of the CH2 carbon, thus reducing the electron pulling effect of the carbonyl , and vice versa. This makes it easier for the carbonyl carbon to pull an electron from the attached hydrogen, releasing a proton to solution. This makes the chlorinated acid a bit stronger than the non chlorinated acid. That is the the basis of the inductive effect. An electron attraction is passed 'down the line' in the structure with effects on groups not directly connected.

To offer help, I need to know where to start from. So do you understand what energy is ? Also do you understand what is internal energy and external energy? I note you have asked this before so the Moderators will probably combine the threads as you are only allowed one thread per topic In your previous thread you gave the formula H = U + PV Does this mean you know the First law of Thermodynamics? : Please write your First law equation down so that I can follow the symbols and sign convention you are used to. I assume you already know what heat and work are but there are different forms of heat (and work). We will cover these. Enthalpy was originally called Heat Content or Total Heat, but that was changed to enthalpy when this became confusing. It is very important to understand that enthalpy is not directly related to the heat transferred in the First Law in most cases.

Good night.

Which has already been agreed. but consider this question from another more mundane point of view. The pistons in my car are moving up and down, the cams are going round and round and the followers are oscillating etc etc. So, rather like your universe, everything is moving round and about everything else. The motion of the pistons, compared to that of the cam followers is different from the motion of the pistons compared to the prop shaft etc etc. They are all in relative motion vis a vis each other and each comparison is different. But there is a further situation overlaid on this. These relationships depend upon the throttle setting, not the motion of the vehicle. They will be the same whether my car is standing 'still' on my driveway or moving down the motorway at 60 mph. All of these motions are compared (ie relative) to the chassis of the car. And even if that chassis is still on the driveway the driveway itself is moving round with the rotation of the surface of the Earth at around 650 mph. But we don't normally consider that. Underlying this build up is the fact that there is no absolute rest frame in the universe. We just pick one and in Relativity it is normally called The Laboratory Frame.

This must be homework ? Is the reaction equation complete? Such a compound has a special name do you know what it is - It begins with the letter C

True since Earnshaw's theorem also applies to gravitational fields. So no observer can be motionless. So once again there is no absolute rest

Thermal break technology is much older than 25 years. But there was a great push by the now infamous double glazing sales brigade in those days. Sorry there is little you can do except replace the frames or use absorbant cloths.

The fact remains he has messed up his primary equation and it is not up to us to fix it. What makes more sense is the fact that the air pressure (whatever its function of r may be) must be a maximum at the centre and decrease towards the surface. Thus if the equation were to be written Pr = P0 - f(r) which says in words that "the pressure at radius r is the pressure at the centre minus some function of the radius (which could be a suitable integral)" As Janus says Pr must equal the surface pressure of the atmosphere at the surface, and thereafter follow perhaps a different function in the atmosphere outside the Earth.

This is not what Martoonsky says.

Which is why more expensive aluminium frames have a thermal break. This is usually a plastic section separating the inner and outer aluminium frames. I take it yours does not?

What is V please?

Thank you for the reply. Are you seriously suggesting that the density (blue or red ???) is zero at the centre? I see that I have misinterpreted your graph. Sorry. So red and blue are different (proposed) values of the product of density and gravity (both of which are functions of r). Fine so you still have both = 0 at the centre so my original statement hold good when substituted into your equation, but P0 now = PR If that maths is incorrect, please provide the correct maths.

Whilst I won't say I have never met such a person I haven't met many. What information do you base your statement on ? It must be clear that unless your statement can be substantiated there is no case to answer M'Lud.

I agree there is a great deal of off topic discussion which makes it difficult for someone studying relativity from the beginning and for those trying to help that person (the OP). +1