michel123456

I am saying that if a natural process agitated the mixture, that is fine and I suppose you can extract from it some safe physical meaning. But not with a cup. Because a cup will NEVER come out from any pure physical process, but the oil/water mixture will. And as much as I can understand you cannot use the oil/water mixture in the Stephen Hawking example.

Because there exist no way for physics to make a cup without the help of a human being. Entropy increasing or decreasing, there is no way. You cannot expect physics to do things it cannot do anyway. The only way for nature to make a cup is to use a living being. And living beings can make objects by assembling things in a way that nature does not.

The cup of tea exists in one single state. that is because a human made the cup in the first place. There was energy and intelligence put into it. What I say is that you cannot "forget" that fact. You cannot begin the analysis from the cup "as if the cup existed just like that", then break the cup and extract a safe conclusion about physics. Take sand, water, air, diamonds (uncut) and you may see that the same way the sand can be dispersed, the same way it can come together and form a rock. Break a desert rose for example. Of course the pieces will not jump together, but if you wait long enough, that may happen, the same way it happened once for the desert rose to form in the first place.

Tell me. My comment was not about entropy. My comment was about the correctness of the use of living things when you want to explain physics. IMHO you cannot do that. You will only get wrong results. ---------------- So that now, in Stephen Hawking's example, you can replace the broken cup of tea with a diamond. The word diamond in the above replaced by me. In this example, one can say that yes, waiting long enough, you will see the diamond being recreated (that was one of the job of Mother Earth these last billion years). And No you will not see the diamond jump on the table, because even in backwards time gravitation is still attractive, from what I remember. What all of this has to do with entropy I don't know. As a side note, if the diamond breaks when falling, you should complain to the seller. And a table is also a by-product of life.

I see we are not communicating very well. Let's go back to the OP. He cites the following What I say is that the cup of tea is a by-product of life. Laws of physics do not allow the presence of a cup of tea in the first place without the intervention of a living being (the human kind in this example). And I think that you cannot expect from simple physics to recreate a cup that it cannot create in the first place anyway. Now if you take a rock falling from a mountain into the sea, you may expect that the rock will not climb to the mountain back. But if you wait long enough (billion of years) you may see a mountain emerge from the sea where the original rock fell in. Because if you are thinking only about the arrow going from order to disorder, then how was the Earth created from a gas cloud? How do galaxies generate stars? How did the galaxies formed from "gas clouds" or anyway? Would that mean that the Earth, the Sun, the Solar System, the Milky Way are some forms of disorder that are the results of something more ordered?

Jesuits are mastering this technique to answer a question with a question. -------------- I asked for a simple analogy. That does not involve cups of tea, milk and coffee, humans and monkeys, plants and seeds. An analogy that you take out of simple non living physical elements. Like salt dissolved in fresh water for example.

An example of the thermodynamic arrow of time, equating entropy and disorder. The cup was an example of Stephen Hawking that the OP cannot understand. My answer to this is that it is a bad analogy. ---------------------- And you still haven't answer my very simple question: What other analogy or example can you find?

What other analogy or example can you find?

I disagree. The origin of the cup is human kind. Take an analogy with a rock and you will see that rocks have been formed. You can crash it in piece, after enough time it may become a rock again. What other example to take? A star, a planet? Do they only dismantle and disappear? Or do they "create"? What other analogy or example can you find? ------------------ Or to say it otherwise: you cannot explain physics on the basis of the behaviour of a monkey.

! Moderator Note this thread is a split from here http://www.scienceforums.net/topic/90145-thermodynamic-arrow-of-time-equating-entropy-and-disorder/ I completely disagree. The example is terribly misleading. The cup is a by-product of life, like an egg, or anything else that has been produced by a living being. And we know that living systems are self-organizing ones. Life create things that do not appear "just like that", as if Life was struggling against entropy. Let's take another example, say a melting iceberg. Of course you will not observe the sea water making back the iceberg. But the melted fresh water of the iceberg will mix with the salt water from the ocean, maybe travel until the tropics, eventually evaporate and form a cloud from which snow will fall and form a new iceberg, in a few thousand years cycle I suppose. But ultimately, yes the iceberg will form again. Simply not in the way we figure, not backwards in time. The book is also a by-product of life. You cannot use it in order to explain physics. Because if you use the living element in your answer, as you did in your question, well yes the broken cup of tea can be fixed by a human, and the pages of the book can be put in the right order again. Better analogies must be taken out of the pure world of physics.

Except if it is a Mandelbrot Electron.

My guess is that it is because you are looking at a circle (the horizon) from a point above. It appears as an ellipse. I remember in the pre-digital epoch, if you were to taken several consecutive pictures with a slight superposition, then collate all the picures together to obtain a panorama, then, if you took all pictures exactly horizontal, then the collage would appear with a curved horizon. In order to correct the effect I used to make a counter-balancing, taking the left picture with a slope to the right, the central picture horizontal, and the right with a slope to the left. http://www.carteravenueframeshop.com/wp-content/uploads/2013/04/Norwegian-family-farm-photo-collage1.jpg That kind of effect.

I am not sure that would be an easily-understood answer. If it is wrong, that's OK. You know better.

A principle is not a force of nature. Wave functions are descriptions, they are not a force of nature either. I'd prefer an explanation that says that the electrons are indeed accelerated and that indeed they do spiral into the nucleus. Take that as a fact, and try to explain back why we are not able to observe anything of it. IOW to describe a collapsing universe from the inside.

And don't tell the landlord about the shark.

That is a constatation, not an explanation. Quantum mechanics is not a force of nature.

"driving"? You mean: you are currently advicing a novice to hit with a hammer the shims with a ton or more of water above his head. A carpenter like you can do that, not everyone.

Well, the entire rest of the world use metrics. Concrete is stronger than wood, I just gave an example of acceptable loads. In metrics. And when I spoke of professional, I ment someone to go there and look at the exact situation, not anyone giving advices over the Net. ------------------ (edit) Loads of 1 ton/m2 are sometimes used in industry buildings for heavy machines. Not in houses.

This will be a case of "reprise de charge" (sorry cannot find the translation). It means you must "take the load" from a floor beam that is not strong enough. To do that you must input a negative charge to the beam (a charge from down to up) prior to bringing your fish tank. It is not so evident because if you put not enough, the whole thing can crash, and if you put too much, the floor can be cracked and damaged. Anyway the weight as indicated in the above posts is way too much. Here in Greece concrete floors are calculated for 250kgs/m2 of movable load. So a good way to proceed is to bring your tank empty, put metallic adjustable scaffold elements beneath (taking care to spot the right emplacement) that you will put on wooden beams on the floor (what is the floor in the crawspace made up?), then fill the tank bit by bit and adjust the elements if needed. Maybe ask for a professional, it can be dangerous if you are not used to do this kind of job. http://i00.i.aliimg.com/img/pb/250/064/490/490064250_745.jpg

You cannot prove that the Earth is a sphere by taking a picture from ground level and expect to observe any curvature of the horizon. In fact, the horizon is the intersection of a cone with a sphere, which is in this particular case a circle. It means that if you are on a ship in the middle of the ocean and look 360 degrees around you, you will see that the horizon line is a circle. It is curved around you but it is flat because geometrically because the circle belongs (also) to a plane. That means that numerous pictures in posts above (like the one of the salt lake) cannot be used. That was to feed the animal. http://apollonius.math.nthu.edu.tw/d1/gc08-exe/9621223/week06/tangent%20cone/tangent%20cone_html.png In this diagram, the horizon is the red circle. On the other hand, it is known from more than two thousands years ago the the Earth is curved. https://en.wikipedia.org/wiki/Eratosthenes And if one is not convinced by the picture from Buzz Aldrin in Swansont post, there is no hope.

If your house is made of bearing walls and if you put your aquarium next to one of those of those bearing walls you should not have any problem. However, an input in metrics would be great, I am not good in imperial units. ------------- Edit If my conversions are correct,from your inputs in gallons and square feet that is about 800kgs/m2. That is way too much. please correct me.

The other astonishing thing is the speed of light in this scaled model. The 8 minutes that takes light from the Sun to reach the Earth corresponds to a slow walk.

Just wanted to share. It is totally insane. The scale I mean, and the void.

Is that so complicated? It means a double rotation. I mean a rotation in X and Y axis, not only on X axis as a planet. I think. But anyway classically that would mean that the particule has some sort of structure, like a left & right side for example.

That's me. But I am the only one to know.