# 2 dimensions into 3 dimensions

Discussion in 'Physics & Math' started by Quantum Quack, May 27, 2017.

1. ### someguy1Registered Senior Member

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The surface of an actual table is a layer of atoms that has quantifiable thickness.

The surface of a mathematical cylinder is a two-dimensional manifold that has no thickness.

Math $\neq$ physics.

3. ### Quantum QuackLife's a tease...Valued Senior Member

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If one describes just one surface of a solid cube is that surface 2 or 3 dimensional?

5. ### DaveC426913Valued Senior Member

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No it isn't. A glass sitting on the table knows nothing of its composition or thickness. It knows the surface only as a 2-dimensional barrier.

7. ### Quantum QuackLife's a tease...Valued Senior Member

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Do the atoms have a 2d surface or not?

8. ### river

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Define atomic " surface " .

9. ### DaveC426913Valued Senior Member

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What a glass on the table experiences.

The table could be a mile thick and the glass doesn't know it. All it knows it the zero thickness surface.

10. ### river

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How does this make sense to you ?

11. ### DaveC426913Valued Senior Member

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How does it not make sense to you?

"Ask" the glass how thick the table is.
The glass will "say" I haven't the foggiest notion. I know it's there because it keeps me from hitting the floor.

12. ### river

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Irrelevant to this discussion , of 2D into 3D .

13. ### Quantum QuackLife's a tease...Valued Senior Member

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Could we consider then that all outer surfaces of any solid are 2 dimensional?

14. ### Q-reeusValued Senior Member

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Formally 2D, but nitpicking might get one into quasi-fractal dimension territory if you really want to drill down to a level where the surface will be rough.
Hey - on track to reach another two digits page count thread. Swell.

15. ### Quantum QuackLife's a tease...Valued Senior Member

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Couldn't have done it without you.

Q-reeus likes this.

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No

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Why not?

18. ### river

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Fractals are only found in life forms , just so we understand .

19. ### Q-reeusValued Senior Member

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Genuine fractals are found nowhere in nature, but only as truncated i.e. quasi-fractals. And certainly not just or even typically in life forms. The quintessential example is coastlines - not living last time I checked.

20. ### river

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Disagree

Fractals , examples of fractals are always based on life .

Give me a fractal that is inorganic .

21. ### Q-reeusValued Senior Member

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Maybe you should type "fractal" into your search bar, and stop at the very first hit, which for me is to a Wikipedia link by the same name. Plenty of inorganic and organic examples of what may be loosely called 'fractals'. As per that article, there is some debate over the proper definition for fractals, and it gets into various categories and sub-categories if one wants to venture in really deep. But, if wishing to persist with that organic-only peculiar restriction - argue it out with the authors of textbooks on the subject who will strongly disagree with you.
Hey, we're still only on page 5! Not good enough. More time wasting banter folks. Come on, we can do this!

22. ### river

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So give an example of this plethora of in-organic fractals .

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