Difference between revisions of "Intuitive feel"

From apm
Jump to: navigation, search
(→‎Brownian motion in nanorobotics: a bit about thermal motion)
m (→‎Everything is "magnetic": spelling)
 
(80 intermediate revisions by the same user not shown)
Line 2: Line 2:
 
This is an introduction to the character of robotic work in the nanocosm. <br>
 
This is an introduction to the character of robotic work in the nanocosm. <br>
 
It should deliver some intuitive feeling of how things work down there.
 
It should deliver some intuitive feeling of how things work down there.
−
 
−
[[File:Atom hair soccer en 3.png|thumb|480px|Pluck yourself a Hair and look at it. Imagine a magnified model of the torn of end was built. Would be interesting – wouldn't it? This model was buried halfway such that it runs vertically into ground at the sidelines and that it reaches twentyfive meters of dome-hight at the center of the playfield. When you stand on this soccer field in front of the fractured surface and you hold a real  hair against tremendous model then you see: The model-atoms of the giant hair have the diameter of a real hair.]]
 
  
 
__TOC__
 
__TOC__
  
−
= How big is an atom? =
+
= Atoms =
  
−
Atoms are quite small but they are not as ridiculously small as people usually say.
+
* How big is an atom?
−
If a hair (0.1mm) would be the width of a soccer field (~60m) an atom would be roughly the size of a hair.
+
"Atoms are unimaginably small." that is very a common belief. And whenever some comparison is brought up one usually feels confirmed on hat assumption.  
−
Carbon is about 0.2nm or 2Å in size that makes roughly five atoms per nanometer.
+
But it turns out that there is a "best way" to get an intuitive feel for their size that is rarely used <small>(or never until here for the first time??)</small>. Here are the details: "[[Magnification theme-park]]". – Judge for yourself whether this "atoms are unimaginably small" belief is false misbelief after all.
−
When hierarchically building up building structures one can quickly fill up this size gap.
+
  
−
<div class="toccolours mw-collapsible mw-collapsed" style="width:100%px">
+
* '''How does it feel when you grab two atoms and rub them against each other?''' <br> Atoms are very soft and slippery. <br>Main article: "[[The feel of atoms]]"
−
Just for comparison astronoical size relations: <div class="mw-collapsible-content">
+
* '''How do atoms work and what shape do they have?''' <br> They work like vibrating drums, just different in all the details. <br>Their shape is like symmetric smooth clouds, a bit like blurred fruit seeds. Shape can change when neighbor atoms change. <br>Main article: "[[The basics of atoms]]"
−
Relative distances in the other (astronomic) direction are vastly greater.
+
* '''At which speeds do Atoms usually move?''' <br>Too fast to find an intuitive way to imagine it. Sorry. <br> The Speed of sound <small>(experienced half a million times faster if you scale up to barely see the model-atoms)</small>. <br><small>But an intuitive feeling for speeds will be attainable for motion of bigger stuff that is of more interest (namely [[crystolecule]]s)</small>. <br>Main article: "[[The speed of atoms]]"
−
If the planetary orbit of our outermost planet Neptune (which can technically be reached in years) where the size of a hair the nearest stars would lie beyond ~1km and the milkiway would be ~1000km thick at our location. The next galaxies would start at the diameter of our sun ~1000000km then still follows the unimaginable size of intergalactic voids, the observable universe and the universe extrapolated to our "now" of which we now little by now.
+
−
</div>
+
−
</div>
+
  
−
= How does it feel when you grab two atoms and rub them against each other? =
+
= Speeds =
  
−
[[File:Novint_Falcon.jpg|thumb|right|Force feedback devices like this one allow one to gain a very intimate understanding of how things behave at the scale of atoms.]]
+
* '''At which speeds do Atoms usually move?''' <br> See answer above in section ''Atoms''. <br>Main article: "[[The speed of atoms]]"
 +
* '''At which speeds will nanorobotics usually operate?''' <br>Pretty slow actually. In the low mm/s range. <br> <small>(experienced pretty fast if you scale up to barely see the model-atoms. About mach 7)</small> <br>Main article: "[[The speed of nanorobotics]]"
  
−
First I should note that trying this out for real is actually possible for quite a while now (as unbelievable as it may sound).
+
= Everything is "magnetic" =
−
To feel atoms you grab the end of a robot (you shake hands with it). A tiny needle with a single atom at the tip is then made to move exactly like your hand just on a lot smaller scale. When the topmost atom on the needle tip starts to touch an atom on a surface the robot arm pushes back just as the surface pushes back on the needle albeit with a magnified force big enough for you to conveniently feel it. This is called force feedback (commonly known from car racing games).
+
  
−
Two analogies that might convey what it feels like best are:
+
Well, it's not really magnetism, but magnetism seems to be the best macroscale analogy for getting across a basic intuitive feeling. 
−
* rubbing soft slippery fish or water soaked gummy bears against each other
+
When going down to the nanoscale one encounters a new force that is omnipresent always and everywhere. The [[Van der Waals force]] (VdW).
−
* moving two magnets past each other in repulsive (but sometimes also attractive) configuration
+
It feels as if everything where magnetic. Everything and anything loose will stick to everything else that it comes too close to.<br>
  
−
Moving the robot arm in and outward you can check out softness and moving sideward you can check out slipperiness.
+
* Similar to the magnetic force we are used to in everyday macroscale life, the VdW force drops off very quickly with distance / is rather short in range. <br>More short range even than magnetism - {{todo|verify quantitatively - low importance}}
 +
* Unlike a magnetic force the VdW force has no polarity. Is always attractive. Well, when things come close enough there's repulsion from [[nonbonded interactions]].<br> (Also related are some means for [[levitation]]).
  
−
== Slipperiness ==
+
The VdW force is extremely useful for putting and holding stuff together at the nanoscale (and maybe microscale). Temporarily during (dis)assembly or permanently in final products. <br>
 +
Even small amounts of contact area can make a bond that is strong enough such that the relentless eternal jostling of [[thermal motion]] [[for all practical purposes]] never suffices to kick loose even one of many [[mol]]s of parts. For more details see: [[Connection method#Van der Waals locking]].
  
−
Atoms are ridiculously slippery. Like the moon orbiting the earth there's basically no friction.
+
Of course from the actual physical origins (and the quantitative effects) the magnetic force and the VdW force are very much different.
−
If certain conditions are met this low friction can be retained for larger contact areas than just the single atom on the tip of our probing needle.  
+
So instead of everything is "magnetic" it would be better to say that everything is "vanderwaalic".
−
One condition is that the atomic ripples on a touching pair of larger surfaces must not interlock like matching egg-crates. If this and a few other things are met there is extremely low friction. It is called the [[superlubrication]] phenomenon and it has enormous potential for technical usage in slide bearings of all kinds.
+
  
−
== Softness ==
+
Side-note: <br>
 +
Instead of using the magnetic force as commonly known macroscale analogy an alternative macroscale analogy would be ''everything is "sticky"''.
 +
This alternate analogy is not used here mainly because:
 +
* stickiness is usually associated with some sort of glue and thus with high viscosity which absolutely does not match reality even as a superficial analogy. Magnetism on the other hand is not associated to any medium and is associated with extremely low friction.
 +
* Magnetism (just as the VdW force) noticeably increases in strength when closing in. Glue does not really behave that way.
  
−
So how does it feel to break a single bond between two atoms?
+
= Everything is extremely bouncy =
−
Since I can't let you pull on this robot arm over the web lets turn the robot arm facing downwards and tie an empty plastic bottle onto it in which we will later fill some water. We can also use a simple coil spring instead of the robot arm giving force feedback
+
  
−
For realism we can make the robot arm behave exactly as stiff as the bond between two atoms.
+
Drop some macroscale machine part like e.g. a metal gear down at a metal surface and it quickly comes to rest.
−
Caution! Please do not mistake stiffness with force. Stiffness is how much the force grows per the length you pull.
+
Not so much at the nanoscale. [[Crystolecules]] behave more like rubber balls, just worse. Way worse.  
−
A bond between two atoms obviously has only a tiny force but this force builds up on a tiny distance.
+
Rubber balls that just do not want to stop bouncing.
−
Thus while the robot arm needs to magnify both force and length the stiffness of the bond turns out to be in the right size such that the robot arm can simulate the it 1:1.
+
  
−
Now here's a quiz: Assuming you fill half a liter of water into the plastic bottle how much will the robot arm simulating the stiffness of a bond between two carbon atoms in diamond give (very roughly)<br> A:~1mm ☐ B:~1cm ☐ C:~1dm ☐
+
<small>Side-note: In some situations (like e.g. a flat disk hitting a flat wall) nanoscale gemstone "bouncyness" can become involved into a serious fight with nanoscale gemstone "vanderwalicness". Working out who wins (bounce-back or snap-to) is a serious mathematical/physical modeling challenge. Experiments are needed, but many of those can't be done yet.</small>
  
−
<div class="toccolours mw-collapsible mw-collapsed" style="width:100%px">
+
That bounciness is not only present when you smash a [[crystolecule]] against a wall, but also (which is more relevant) in the operation of gemstone based nanomachinery. Flex waves can run back and forth, barely damped, long ways through complex and even branched axle systems.
−
Hidden solution:
+
−
<div class="mw-collapsible-content">
+
−
* A bond between two carbon atoms in (C-C bond) in diamond has a (maximum) spring constant of: k = 440N/m =~ 450g/cm. <br>Thus half a liter of water which makes 500g bends the setup ~1cm so the answer is B:~1cm ☒. That feels pretty soft to the hand.
+
−
* halving the size -> halves the stiffness ... this is an instance of a scaling law of whom you'll here a lot here
+
−
* Just remember: '''The smaller things are the floppier they become.''' Even diamond one of the strongest materials in existence feels pretty soft at the scale of single atomic bonds.
+
−
</div>
+
−
</div>
+
  
−
= What happens when you let go of a building block? =
+
While designing for this can be major PITA (ahem pretty difficult) like in electrical circuit design,
 +
it also potentially offers the possibility to archive extreme high efficiencies.
 +
 
 +
Also one can gain more control via deliberate introduction of discrete damping elements.
 +
 
 +
= Everything is shaky =
 +
 
 +
Worse than in a wood wheeled carriage racing over cobblestones.<br>
 +
'''Or: You are like an astronaut – don't ever let go of your tools – they may haunt you'''
 +
 
 +
* What happens when you let go of a building block?  
 +
 
 +
Main article: "[[The heat-overpowers-gravity size-scale]]"
  
 
Let's consider an somewhat unusual fall experiment. A small gripper let go of a building block. Simple? See if you answer right.
 
Let's consider an somewhat unusual fall experiment. A small gripper let go of a building block. Simple? See if you answer right.
 +
 +
Related: [[spiky needle grabbing]]
  
 
[[File:Fall-experiment-quiz-en.svg|thumb|center|480px|A fall experiment quiz to illustrate the quite unfamiliar mechanical behavior in the nanoscale.]]
 
[[File:Fall-experiment-quiz-en.svg|thumb|center|480px|A fall experiment quiz to illustrate the quite unfamiliar mechanical behavior in the nanoscale.]]
Line 73: Line 77:
 
More details can be found at the [[scaling laws|scaling laws main page]].
 
More details can be found at the [[scaling laws|scaling laws main page]].
  
−
= The feel of AP Products =
+
= The prospective feel of gem-gum products =
  
−
AP products though robotic and gemstone like in the nanocosm are not necessarily cold hard and robot like to the human senses.
+
Gem-gum products though machine like robotic in the nanocosm are not necessarily cold hard and robot like to the human senses (See: [[Soft-core macrorobots with hard-core nanomachinery]]).
−
[[Emulated elasticity]] can create any form imaginable with gradients from soft to hard. It isn't an easy to attain property but it is an highly desirable one and will emerge at some point.
+
[[Emulated elasticity]] can create any form imaginable with gradients from soft to hard.  
 +
It isn't an easy to attain property but it is an highly desirable one and will emerge at some point.
  
−
= Bonding energies - Tensile strengths - Stiffnesses =
+
= Related =
  
 +
Provide means for an intuitive understanding seems to be
 +
a good [[didactic approach]] for a wide [[target audience]].
  
−
{{todo|Add the same info table as on VdW force page}} <br>
+
== In the book "Radical Abundance" ==
−
['''Todo:''' Add table - make it visualizable for covalent bonds and VdW bonds] <br>
+
−
['''Todo:''' show surface area thats VdW ashesion is energetically equivalent to one covalent bond - related: [[Form locking]]]
+
  
−
* [[Connection method#Van der Waals locking]]
+
In the book [[Radical Abundance]] the introduction tries to convey an intuitive feel for how things behave down at the nanoscale.
−
* [[Van der Waals force]]
+
{{wikitodo|give a more precise reference}}
  
−
= Brownian motion in nanorobotics =
+
== Richard Feynman ==
  
−
* [https://upload.wikimedia.org/wikipedia/commons/4/4d/Huellkurve_wurfparabel.svg Envelope of throwing trajectories with same speed]
+
There are great recordings of the famous physicist and teacher Richard Feynmen about the importance:
−
* [https://commons.wikimedia.org/wiki/File:Inclinedthrow.gif Throwing trajectories with various speed in same direction]
+
* of an intuitive understanding of things and
 +
* of looking at things from new perspectives.
  
−
Thermal motion at the nanoscale is pretty incredible. Small single molecules zip around at thermal speeds of a few hundred meters per second. That's about the speed of sound. When we scale up by our usual magnification factor of 500.000 to make model atoms (say water molecules) have the diameter of a human hair and when we keep the flow of time unchanged those hair sized molecules zip around with more than half the speed of light. It becomes very obvious that in an environment densely packed with other (water) molecules they meet a lot of these other molecules in a very short amount of time. With bigger more complex shaped molecules it's not that extreme but still very fast.
+
Main article: [[Richard Feynman]]
  
−
This is why puzzle piece shaped proteins molecules in biological systems can assemble themselves into their intended products. They just try all places in very very fast succession. Like in a brute force computer algorithm.
+
== Related ==
−
This [[thermally driven assembly]] that is found in biology will probably be very useful for the path to advanced nanofactories but as it turns out in a advanced nanofactory (the far term goal) it is makes sense to actually constrain thermal vibrations and take care for transport oneself.
+
−
Just like we learned to suppress thermally caused electrical noise in microchips and now use mostly digital electronics instead of analogous electronics.
+
−
Assembly in an advanced nanofactory will resemble more of a factory assembly line far away from any similarity to biological systems. All the machinery will usually run much slower (about a factor of 1000) than those thermal motions.
+
  
−
= Further =
+
=== Getting a good intuition about atoms ===
 +
 
 +
* [[Intuitively understanding the size of an atom]]
 +
* [[The feel of atoms]]
 +
* [[The basics of atoms]]
 +
* [[The speed of atoms]] – [[The speed of nanorobotiocs]] and ...
 +
* ... how the two are usually far apart: [[Stroboscopic illusion in crystolecule animations]]
 +
* [[Periodic table of elements]] as the ultimate construction toy
 +
* [[Limits of construction kit analogy]]
 +
 
 +
For an intuitive understanding how energies, forces, and stiffness <br>
 +
at the nanoscale compare to each other see: [[Energy, force, and stiffness]]
 +
 
 +
=== Getting a good intuition about thermal motions ===
 +
 
 +
* [[The heat-overpowers-gravity size-scale]]
 +
* [[thermally skittering building blocks]]
 +
* [[thermally jumping building blocks]] – practically likely not happening except designed for – [[spiky needle grabbing]]
 +
 
 +
=== Averting false intuitions – things that may come unexpected ===
  
−
* [[Periodic table of elements]]
 
−
* acceleration limits
 
−
* jumping building blocks
 
 
* Why [[nanomechanics is barely mechanical quantummechanics]]
 
* Why [[nanomechanics is barely mechanical quantummechanics]]
 +
* [[Soft-core macrorobots with hard-core nanomachinery]]
 +
* The [[unsupported rotating ring speed limit]]
 +
* [[Scaling law]]s
 +
 +
=== Truely intuitively understanding the size scales involved ===
 +
 +
* [[Maginification theme park]]
 +
* [[Intuitively understanding the size of an atom]]
 +
* [[Distorted visualisation methods for convergent assembly]]
 +
 +
=== An intuition about the possible consequences of gemstone metamaterial technology ===
 +
 +
* Understanding possible consequences of [[gem-gum technology]] via [[story scenarios]].
 +
 +
= External links =
 +
 
* '''Video Playlist:''' [https://www.youtube.com/watch?v=BjGP0iXhsr8&list=PLG7lwFsqKHb8_24MArWWW9IgYQtieV8BR The Shape of Atoms and Bonds (By "Learn Hub")]
 
* '''Video Playlist:''' [https://www.youtube.com/watch?v=BjGP0iXhsr8&list=PLG7lwFsqKHb8_24MArWWW9IgYQtieV8BR The Shape of Atoms and Bonds (By "Learn Hub")]
  
 
[[Category:General]]
 
[[Category:General]]

Latest revision as of 13:15, 8 July 2021

This is an introduction to the character of robotic work in the nanocosm.
It should deliver some intuitive feeling of how things work down there.

Atoms

  • How big is an atom?

"Atoms are unimaginably small." that is very a common belief. And whenever some comparison is brought up one usually feels confirmed on hat assumption. But it turns out that there is a "best way" to get an intuitive feel for their size that is rarely used (or never until here for the first time??). Here are the details: "Magnification theme-park". – Judge for yourself whether this "atoms are unimaginably small" belief is false misbelief after all.

  • How does it feel when you grab two atoms and rub them against each other?
    Atoms are very soft and slippery.
    Main article: "The feel of atoms"
  • How do atoms work and what shape do they have?
    They work like vibrating drums, just different in all the details.
    Their shape is like symmetric smooth clouds, a bit like blurred fruit seeds. Shape can change when neighbor atoms change.
    Main article: "The basics of atoms"
  • At which speeds do Atoms usually move?
    Too fast to find an intuitive way to imagine it. Sorry.
    The Speed of sound (experienced half a million times faster if you scale up to barely see the model-atoms).
    But an intuitive feeling for speeds will be attainable for motion of bigger stuff that is of more interest (namely crystolecules).
    Main article: "The speed of atoms"

Speeds

  • At which speeds do Atoms usually move?
    See answer above in section Atoms.
    Main article: "The speed of atoms"
  • At which speeds will nanorobotics usually operate?
    Pretty slow actually. In the low mm/s range.
    (experienced pretty fast if you scale up to barely see the model-atoms. About mach 7)
    Main article: "The speed of nanorobotics"

Everything is "magnetic"

Well, it's not really magnetism, but magnetism seems to be the best macroscale analogy for getting across a basic intuitive feeling. When going down to the nanoscale one encounters a new force that is omnipresent always and everywhere. The Van der Waals force (VdW). It feels as if everything where magnetic. Everything and anything loose will stick to everything else that it comes too close to.

  • Similar to the magnetic force we are used to in everyday macroscale life, the VdW force drops off very quickly with distance / is rather short in range.
    More short range even than magnetism - (TODO: verify quantitatively - low importance)
  • Unlike a magnetic force the VdW force has no polarity. Is always attractive. Well, when things come close enough there's repulsion from nonbonded interactions.
    (Also related are some means for levitation).

The VdW force is extremely useful for putting and holding stuff together at the nanoscale (and maybe microscale). Temporarily during (dis)assembly or permanently in final products.
Even small amounts of contact area can make a bond that is strong enough such that the relentless eternal jostling of thermal motion for all practical purposes never suffices to kick loose even one of many mols of parts. For more details see: Connection method#Van der Waals locking.

Of course from the actual physical origins (and the quantitative effects) the magnetic force and the VdW force are very much different. So instead of everything is "magnetic" it would be better to say that everything is "vanderwaalic".

Side-note:
Instead of using the magnetic force as commonly known macroscale analogy an alternative macroscale analogy would be everything is "sticky". This alternate analogy is not used here mainly because:

  • stickiness is usually associated with some sort of glue and thus with high viscosity which absolutely does not match reality even as a superficial analogy. Magnetism on the other hand is not associated to any medium and is associated with extremely low friction.
  • Magnetism (just as the VdW force) noticeably increases in strength when closing in. Glue does not really behave that way.

Everything is extremely bouncy

Drop some macroscale machine part like e.g. a metal gear down at a metal surface and it quickly comes to rest. Not so much at the nanoscale. Crystolecules behave more like rubber balls, just worse. Way worse. Rubber balls that just do not want to stop bouncing.

Side-note: In some situations (like e.g. a flat disk hitting a flat wall) nanoscale gemstone "bouncyness" can become involved into a serious fight with nanoscale gemstone "vanderwalicness". Working out who wins (bounce-back or snap-to) is a serious mathematical/physical modeling challenge. Experiments are needed, but many of those can't be done yet.

That bounciness is not only present when you smash a crystolecule against a wall, but also (which is more relevant) in the operation of gemstone based nanomachinery. Flex waves can run back and forth, barely damped, long ways through complex and even branched axle systems.

While designing for this can be major PITA (ahem pretty difficult) like in electrical circuit design, it also potentially offers the possibility to archive extreme high efficiencies.

Also one can gain more control via deliberate introduction of discrete damping elements.

Everything is shaky

Worse than in a wood wheeled carriage racing over cobblestones.
Or: You are like an astronaut – don't ever let go of your tools – they may haunt you

  • What happens when you let go of a building block?

Main article: "The heat-overpowers-gravity size-scale"

Let's consider an somewhat unusual fall experiment. A small gripper let go of a building block. Simple? See if you answer right.

Related: spiky needle grabbing

A fall experiment quiz to illustrate the quite unfamiliar mechanical behavior in the nanoscale.

Scaling laws

They describe what changes when one goes down the scale. E.g. that magnetic motors become weak but electrostatic ones strong. More details can be found at the scaling laws main page.

The prospective feel of gem-gum products

Gem-gum products though machine like robotic in the nanocosm are not necessarily cold hard and robot like to the human senses (See: Soft-core macrorobots with hard-core nanomachinery). Emulated elasticity can create any form imaginable with gradients from soft to hard. It isn't an easy to attain property but it is an highly desirable one and will emerge at some point.

Related

Provide means for an intuitive understanding seems to be a good didactic approach for a wide target audience.

In the book "Radical Abundance"

In the book Radical Abundance the introduction tries to convey an intuitive feel for how things behave down at the nanoscale. (wiki-TODO: give a more precise reference)

Richard Feynman

There are great recordings of the famous physicist and teacher Richard Feynmen about the importance:

  • of an intuitive understanding of things and
  • of looking at things from new perspectives.

Main article: Richard Feynman

Related

Getting a good intuition about atoms

For an intuitive understanding how energies, forces, and stiffness
at the nanoscale compare to each other see: Energy, force, and stiffness

Getting a good intuition about thermal motions

Averting false intuitions – things that may come unexpected

Truely intuitively understanding the size scales involved

An intuition about the possible consequences of gemstone metamaterial technology

External links

Retrieved from "http://apm.bplaced.net/w/index.php?title=Intuitive_feel&oldid=11357"