studiot

There's been a lot of talk of uncertainty. This is my last post on the subject because it really is off topic as it makes no difference if you cool something to absolute zero. That takes time. In fact the third law says infinite time. but you can warm it back up again also in time. So zero time is not involved. All those introducing uncertainty should calculate it, remembering that we are talking about the movement of massive objects like atoms or molecules, not electrons. What is the uncertainty relative to the size of the atom and its uncertainty?

Until we know exactly what process moreno has in mind, how can we decide if it is reversible or not?

Yup it takes a supernova to make the heavy elements. Cain't be did in ordnary stars.

Acid + Base = Salt + water. But the salt is soluble so stays in solution.

One further comment to add to Ophiolite's ecstacy. The so called packing fraction curve determines that energy will be released by fusion for elements up to iron in the periodic table, and that causing fission of these elements requires an input of energy. This is the normal process within stars. The building up of lighter elements to heavier ones as far as iron. Conversely beyond iron in the table the positions are reversed. Fission now releases energy and fusion requires energy input. So to build up the elements heavier than iron (a great deal of) energy input is required. This is achieved in supernovae, not ordinary stars. When the supernova explodes its material over a region of space, the material then contains the heavier radioactive elements which seed the resulting stellar and planetary systems.

the drakensbnerg

Agreed in QM. But classically the Third Law sets S=0 at T=0 so that the integration of TdS from zero to any desired temperature may be perfomed to obtain the so named absolute entropy. In those calculations zero point energy is not included. Further discussion here https://van.physics.illinois.edu/qa/listing.php?id=22970

To reinforce John's comment. The statement that motion ceases at absolute zero is disingenuous because the full statement is The vibrational motion of the atoms of a perfect crystal approaches zero as the temperature approaches absolute zero. That is not to say that other forms of motion is forbidden, even for instance simple translational motion of the crystal itself.

A Wave is global. That is it extends to or is defined for a very significant part of space or even all space. A Particle is local. That is the particle and all its properties only extend over a very small region of space, perhaps even just a point. The whole dichotomy is that real world objects seem to exhibit both of the mutually exclusive characteristics in some measure. Normally one of these characteristics dominates the other so we call the real world object a wave or a particle to suit.

I don't think this thread is meant to be about the proof or substantiation of the Second Law. I don't know what moreno really wants since although he has been back to this thread he has chosen not to clarify his original post as I invited him to do. The Wiki quote is inapplicable to classical themodynamics, which was clearly stated for a cyclic process only. Further the Wiki statement, which is basically the inequality of Clausius, is useless in cases where q = 0. Discussion about entropy in these cases is like discussing the direction the zero vector points in. Moreno's proposed a case which can be theoretically realised in the mechanical world (q=0) and I am happy to delve more deeply into the thermodynamic mathematics of this so long as he is not asking us to do all the work.

I suppose that your route to the second law must depend upon which formulation you want to reach. But I don't see this question is really about Maxwell's demon. In any event, thank you for the reference I might look at it as it seems interesting. But there are quite a few books about the philosophical underpinnings of the second law. Professor's Atkins little book, Four Laws that Drive the Universe, is particularly good as it does this for all four of them.

The Earth gains material over time, rather than looses it, albeit ever more slowly. Current theory has that the proto Earth swept up much of the hot gas, dust and larger particles local to it. This process of accretion was reinforced by the fact that as the largest local object was the Earth which therefore attracted local matter and gre at the expense of smaller bodies. Thus the Earth's locality in space now has been swept relatively clean of such material which has long been incorporated in the Earth. Again current theory has the temperature of the molten out core hotter than the surface of the Sun. So there is a thermodynamic imperative to radiate vast quantiies of energy, like the Sun. However, unlike the Sun the core is covered by an insulating blanket called the mantle. The attempt by the heat to get out is what drives the plate tectonics (whichever version you favour) that takes place on Earth.

The part 'Thermo' of the word should give you a clue that themodynamics is something to do with heat, and the rest of the word is about changes. In fact we think of thermodynamics as being about heat and its relationship with other forms of energy so I would expect the toy to reflect this in some way. I suppose you could argue that the change in bond energies in battery powering the car reflects a thermodynamic change, but search your soul and ask yourself "Is this a good visible and obvious demonstration of Thermodynamics in action?" The variable that appears in thermodynamics that does not generally appear in mechanics is temperature so I would expect the operation of the toy to have some connection to temperature.

I'm going to beat the Second Law I'm going to beat the Second Law I'm going to beat the Second Law As far as the underlined part you are correct. But in attacking the Second Law, you have forgotten the First Law (which is the underlined bit). Did you have such a system in mind that we can analyse in full? Simple versions of such systems are easy to describe. The (transfer of) work eventually damps out the oscillations. Indeed study of the problem leads to the conclusion that an isolated system that can only undergo reversible processes cannot proceed by itself from one equilibrium state to another.

No, you weren't to know if you have never met them. They are just very well known in technical circles because they are very useful for what they are. Interesting,your choice of texamples about Venn diagrams. I have in mind something similar (Men, Women, Marriage) to show something to another poster (in another thread) here about a case, not mentioned on Wikipedia, (a mathematical term) of surjections . I only wish he had the same approach to discussion you have.

http://www.bbc.co.uk/news/science-environment-34963515

What a pity you did not wait for my thoughts in reply to your post16. I have been preparing one of my 'rough guides' this afternoon. But this takes a measure of time and effort. Normally a student of this subject would take around 6 months to cover the material, you say you have not studied, and that I am trying to pull together for you in an afternoon. Many very clever people from many countries spent 150 years or so pulling and pushing, arranging and rearranging this theory into a shape where it is not only the foundation for a great deal of traditional mathematics but provides a springboard for generalisation beyond the numbers. As such the modern theory is in pretty good shape and does not need a rather flaky competitor. Talking of measure, you are struggling because you are lacking the idea of measure or distance or metric. Without this your statement has no meaning. What is a gap? What is touching? What is adjacent? For your information modern theory recognises three types of set points, not two. The three types are as I listed in post 15. Since you have now introduced continuity and connectedness the terms Complete, Compact, Continuous, Connected and Covering all have special (very carefully defined) meanings in relation to this subject. Just to be going on with until I complete my rough guide and to show that connected (=no gap) is a complicated concept here is an extract courtesy Buck Advanced Calculus.

I agree with John Cutheber, that you need to be confident in electronics before you start making your own mains driven stuff. You 30 volt supply is safe but unwieldy. Here is a robust cheap module that will add on to it to make a variable supply that includes a voltmeter and is short circuit proof. There are many available at around £6 including postage the link is an example supply. http://www.ebay.co.uk/itm/LM317-Adjustable-Voltage-Regulator-Step-down-Power-Supply-Module-W-LED-5KR8/181887572382?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D33196%26meid%3D499427c93d3b44eea3a096e73829d5c1%26pid%3D100005%26rk%3D4%26rkt%3D6%26sd%3D331280958905#ht_9870wt_1059

Have you come across the idea of interior, boundary and exterior points? Or the idea of a neighbourhood?

Xerxes, go well with your intervention. We have been through a long, exhausting and exasperating thread with the OP on just this subject. http://www.scienceforums.net/topic/92509-cardinality-of-the-set-of-binary-expressed-real-numbers/

Here is my Rough Guide to Electrolysis. Both safety and voltage depend upon what you want to electrolyse. Basically the higher the voltage the faster the electrolysis process so 30v may produce some rather rapid fizzing with some solutions. For experimental purposes some way of varying the voltage is highly desirable. Electrolysis works like this Above some threshold (which may be close to zero) the greater the voltage the greater the current and the faster the elctrolysis proceeds. This can be seen in the two curves shown in the sketch. The threshold voltage is called the experimental decomposition voltage and is about 1.7 volts for sulphuric acid. Some solutions release noxious or explosive gases on electrolysis, some are hazardous in themselves. For instance the electrolysis of copper sulphate is OK with copper electrodes but the sulphuric acid requires platinum electrodes or they will be eaten away.

I am sorry, I am clearly wasting my time. We have a saying in English. You can lead a horse to water. But you can't make him drink. I feel exactly this way seeing your last post.

Domain and codomain are not really the language of set theory but my proposed discussion covers and explains this. Bijections are special because they involve every member of both sets. There is a great deal of mathematical terminology to absorb and much of it seems pointless pedantry to the beginner. My whole idea is to ease this by setting the terms in context, showing why we need them as they are, and how they relate to other terms discussed in the same manner. Doing this involves some effort on my part so I will only bother if you are really interested, not just being polite. and I am still having trouble determining this?

You say you are a new high school student. Did you miss a term or some lessons? Has your class already started differentiation? The formula for the volume of a cylinder is [math]V = \pi {r^2}L[/math] Differentiate with respect to r [math]\frac{{dV}}{{dr}} = 2\pi rL[/math] Rearrange to obtain your formula [math]dV = 2\pi rLdr[/math] Does any of this mean anything to you?

Perhaps folks are just fed up with proving you wrong; then you just carry on with the same mis-statements as though the disproof had not happened. I wonder if you had the same teacher that produced this GCSE drivel "Food Technology and Design with Food as the Focus Material."