What is the reason for the Emergence of properties?

  • #1

Main Question or Discussion Point

Water molecule has different properties from either oxygen or hydrogen atom.

My question is 'Are these properties of water molecules totally new or were these properties already lurking around in the oxygen and hydrogen atoms?'

Thanks.
 

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  • #2
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It's hard to judge that but both hydrogen and oxygen are in many other molecules whose properties are nothing like water. So I think it would be reasonable to say they are properties of the way the water molecule is formed, rather than the individual atoms.
 
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  • #3
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My question is 'Are these properties of water molecules totally new or were these properties already lurking around in the oxygen and hydrogen atoms?'
How would you experimentally test the difference between these two options? I.e. What experiment would yield X if "the properties are totally new" or yield Y if "the properties are already lurking around".
 
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  • #4
sophiecentaur
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Water molecule has different properties from either oxygen or hydrogen atom.

My question is 'Are these properties of water molecules totally new or were these properties already lurking around in the oxygen and hydrogen atoms?'

Thanks.
I am not sure exactly what you want to know but I will hazard a guess.
You appear to be asking about the way that molecular bonding and reactivity works. It depends upon the relative energies binding the outer electrons to individual (separate) atoms and the energies binding atoms together in a molecule.
Look at the reactivities of elements in a particular group of the periodic table. Groups 1 and 7 are the easiest to discuss. They all have the same number of outer electrons (Group 1) or 'missing electrons' (Group 7) in the shells and behave in a similar way, chemically, but the presence of more inner shells as you go down the group affects the reactivity because of the shadowing effect between the + Nucleus and any nearby electrons. Group 1 get more reactive and Group 7 become less reactive for the lower periods.
Those basic energies are 'built in' for each element and so they will be mirrored in the mechanical strengths or reactivities of molecules they are part of.
 
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  • #5
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Water molecule has different properties from either oxygen or hydrogen atom.

My question is 'Are these properties of water molecules totally new or were these properties already lurking around in the oxygen and hydrogen atoms?'

Thanks.
I know that you are talking about just 3 atoms forming a molecule here, but maybe this is a good jumping point for you to discover another new aspect of our world that Phil Anderson touted many years ago: More Is Different.

Zz.
 
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  • #6
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I think as a general rule a compound has entirely different properties to the atoms from which is built. Consider the highly reactive and dangerous metal sodium and the highly reactive and dangerous gas chlorine. When the two react together you get the relatively benign compound sodium chloride what you sprinkle on your fish and chips.
 
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  • #7
sophiecentaur
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I think as a general rule a compound has entirely different properties to the atoms from which is built. Consider the highly reactive and dangerous metal sodium and the highly reactive and dangerous gas chlorine. When the two react together you get the relatively benign compound sodium chloride what you sprinkle on your fish and chips.
With a hundred or more elements to choose from, there will be many different of examples of compounds - some of which follow and some which go against the idea. My point was that, as you go down the group, the resulting products are similar but the details of their different properties are reflected by the period of Element X in the molecule XYZ. For instance, it is easier to isolate Lithium back from Lithium Oxide than it is to get back Rubidium from Rubidium Oxide. The differences from group to group are probably a lot harder to identify but there are examples where adding a different element to, say, steel, will alter its properties. Carbon Chemists can supply examples of how adding an odd atom of an element can change the properties of a plastic.

I guess the point should be made, for the OP, that the 'Properties' and the "lurking" are very much nuts and bolts things are often not too hard to identify for a Chemist. (Of which I am not one, for what it's worth.)
 
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  • #8
Thanks everyone for judicious answers...

What I wanted to ask is actually very laymanish...

Suppose, I have a large structure through which I can move and so on. But when I go up and get a bird's eye view of the same structure, I get to see a pattern/shape which was not visible from the ground.

Is this pattern/shape an emergent property of the structure ? My question was of this connotation...
 
  • #9
sophiecentaur
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Is this pattern/shape an emergent property of the structure
There is one common example of what you seem to be implying. The basic shape of the molecules in a crystal have a direct bearing on the shape and symmetries of that crystal.
 
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  • #10
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Is this pattern/shape an emergent property of the structure ?
What experiment could you perform that would yield X if it is an emergent property or Y if it is not?

I am not asking this to be a pain. It is an important mental step that is necessary in order for you to think about your own question scientifically.
 
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  • #11
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Picking the right property, Y, is critical. The answer probably depends on the property.

For certain properties, there might be known explanations that can answer the question without needing to define a test.
 
  • #12
What experiment could you perform that would yield X if it is an emergent property or Y if it is not?

I am not asking this to be a pain. It is an important mental step that is necessary in order for you to think about your own question scientifically.
I can't think of any such experiment.

So, do you mean to say the answer is unknowable?
 
  • #13
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I can't think of any such experiment.

So, do you mean to say the answer is unknowable?
No, I mean to say that the question is not about physics or nature. The question is a philosophical question. You can define the terms like "emergent" and "property" such that you get any answer you like, and it doesn't change anything physical, it just changes your philosophical approach.

So, now that you understand that the question is philosophical, you can start thinking through the question and answers. Do you want a particular answer? If so, then concentrate on defining "emergent" and "property" such that you get your desired answer. If not, then you will need to pick some other way of defining your terms, and then see the logical consequences.
 
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  • #14
No, I mean to say that the question is not about physics or nature. The question is a philosophical question. You can define the terms like "emergent" and "property" such that you get any answer you like, and it doesn't change anything physical, it just changes your philosophical approach.

So, now that you understand that the question is philosophical, you can start thinking through the question and answers. Do you want a particular answer? If so, then concentrate on defining "emergent" and "property" such that you get your desired answer. If not, then you will need to pick some other way of defining your terms, and then see the logical consequences.
Thanks for a brilliant answer....

But in physics also we surely talk about emergent properties that are related to structure of atoms /molecules.

And they ain't philosophical questions.
 
  • #15
sophiecentaur
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I'm not sure it's a term I have ever used. There is a fuzzy sort of relationship between the atomic and bulk properties but there will be many exceptions so I wonder whether it is worth while spending too much time on it.
If there were a strong correlation then it could help with Chemical Engineering - like adding element Y to a whole range of plastics to give them all improved strength or higher melting points. I would guess that many people will have tried to formalise that sort of process; it would be worth a lot of money.
 
  • #16
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But in physics also we surely talk about emergent properties that are related to structure of atoms /molecules
You may want to refer to those sources where you have heard about emergent properties related to the structure of atoms and see if they clearly define any of the relevant terms.

And they ain't philosophical questions.
If there is not an experiment to make the distinction then it is philosophical. Experiment is the key differentiator between philosophy and science.
 
  • #17
You may want to refer to those sources where you have heard about emergent properties related to the structure of atoms and see if they clearly define any of the relevant terms.

If there is not an experiment to make the distinction then it is philosophical. Experiment is the key differentiator between philosophy and science.
I have thought of an experiment (unless you rubbish it)

Let's take a quantum field. There is no excitation in it (suppose).

Then someone observes it and the excitation of the quantum field gets manifested in the form of an elementary particle.

To my mind this is the experimental proof of an emergent property. In other words the elementary particle in question is the emergent property of the underlying quantum field.

Does this make sense?
 
  • #18
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I have thought of an experiment (unless you rubbish it)

Let's take a quantum field. There is no excitation in it (suppose).

Then someone observes it and the excitation of the quantum field gets manifested in the form of an elementary particle.

To my mind this is the experimental proof of an emergent property. In other words the elementary particle in question is the emergent property of the underlying quantum field.

Does this make sense?
So for clarity, any interaction which increases the number of fundamental particles demonstrates an emergent property of the original system? Is that correct

What about interactions which reduce the number of fundamental particles? What about interactions that preserve the number of fundamental particles but change their type?
 
  • #19
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Then someone observes it and the excitation of the quantum field gets manifested in the form of an elementary particle.

Does this make sense?
No. Observation doesn't make particles appear out of nowhere.

To my mind this is the experimental proof
It's not a proof of anything, nor is it an experiment.
 
  • #20
What about interactions which reduce the number of fundamental particles? What about interactions that preserve the number of fundamental particles but change their type?
I think these also would be called emergent properties because something has happened to the quantum field that was not there before.
 
  • #21
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I think these also would be called emergent properties because something has happened to the quantum field that was not there before.
What was not there before? It is not clear from your sentence.

To my mind this is the experimental proof of an emergent property. In other words the elementary particle in question is the emergent property of the underlying quantum field.
It seems that your definition of "emergence" is not quite the usual one in science and philosophy. Would you consider ice an emergent "property" of water?
https://en.wikipedia.org/wiki/Emergence
 
  • #22
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I think these also would be called emergent properties because something has happened to the quantum field that was not there before.
This seems like an odd definition of emergent properties that I have not seen elsewhere. But it is just a definition, so OK.

Then water would have no emergent properties since it is the same number and kind of fundamental particles as water or as separate hydrogen and oxygen atoms. That doesn't bother me, but I am not sure that is what you really want.

It may be best to check the literature and use standard definitions
 
  • #23
This seems like an odd definition of emergent properties that I have not seen elsewhere. But it is just a definition, so OK.

Then water would have no emergent properties since it is the same number and kind of fundamental particles as water or as separate hydrogen and oxygen atoms. That doesn't bother me, but I am not sure that is what you really want.

It may be best to check the literature and use standard definitions
I have checked the standard definitions. These call turbulence, temperature, pressure Etc. as emergent properties.

I am just a layman but I think I am also saying the same thing.

I think 'something happening' to the quantum field is the 'fundamental' emergence. All other cases of emergence (e.g water) are just cases of secondary /tertiary emergence, IMHO.
 
  • #24
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I have checked the standard definitions. These call turbulence, temperature, pressure Etc. as emergent properties.
I don't see how that fits with your definition. Turbulent flow and laminar flow of the same fluid should have the same numbers and types of fundamental particles. So per your definition it would not be emergent, in contrast to the standard usage.
 
  • #25
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Humpty Dumpty smiled contemptuously. 'Of course you don't — till I tell you. I meant "there's a nice knock-down argument for you!"'

'But "glory" doesn't mean "a nice knock-down argument",' Alice objected.

'When I use a word,' Humpty Dumpty said, in rather a scornful tone, 'it means just what I choose it to mean — neither more nor less.'

'The question is,' said Alice, 'whether you can make words mean so many different things.'

'The question is,' said Humpty Dumpty, 'which is to be master — that's all.'

Alice was too much puzzled to say anything; so after a minute Humpty Dumpty began again. 'They've a temper, some of them — particularly verbs: they're the proudest — adjectives you can do anything with, but not verbs — however, I can manage the whole lot of them! Impenetrability! That's what I say!'
Can we please use standard definitions?
 
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