Difference between revisions of "Intuitive feel"

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= How big is an atom? =
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= Atoms =
  
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'''False claim?''' "Atoms are unimaginably small."<br>
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* How big is an atom?
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That's commonly assumed. And whenever some comparison is brought up one usually feels confirmed on hat assumption.
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"Atoms are unimaginably small." that is very a common belief. And whenever some comparison is brought up one usually feels confirmed on hat assumption.  
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Turns out that there is a "best way" to get an inuitive feel for their size that is rarely (or never) used.<br>
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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.
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Here are the details: "[[Magnification theme-park]]". – Judge yourself.
+
  
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= How does it feel when you grab two atoms and rub them against each other? =
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* '''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]]"
 +
* '''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]]"
 +
* '''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]]"
  
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[[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.]]
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= Speeds =
  
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First I should note that trying this out for real is actually possible for quite a while now (as unbelievable as it may sound).  
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* '''At which speeds do Atoms usually move?''' <br> See answer above in section ''Atoms''. <br>Main article: "[[The speed of atoms]]"
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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).
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* '''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]]"
  
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Two analogies that might convey what it feels like best are:
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= Everything is "magnetic" =
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* rubbing soft slippery fish or water soaked gummy bears against each other
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* moving two magnets past each other in repulsive (but sometimes also attractive) configuration
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Moving the robot arm in and outward you can check out softness and moving sideward you can check out slipperiness.
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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.<br>
  
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== Slipperiness ==
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* 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]]).
  
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Atoms are ridiculously slippery. Like the moon orbiting the earth there's basically no friction.
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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>
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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.  
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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]].
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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.
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== Softness ==
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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".
  
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So how does it feel to break a single bond between two atoms?
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Side-note: <br>
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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
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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.
  
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For realism we can make the robot arm behave exactly as stiff as the bond between two atoms.
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= Everything is extremely bouncy =
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Caution! Please do not mistake stiffness with force. Stiffness is how much the force grows per the length you pull.
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A bond between two atoms obviously has only a tiny force but this force builds up on a tiny distance.
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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 it 1:1.
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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 ☐
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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.
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Rubber balls that just do not want to stop bouncing.
  
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<div class="toccolours mw-collapsible mw-collapsed" style="width:100%px">
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<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>
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Hidden solution:
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<div class="mw-collapsible-content">
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* 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.
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* halving the size -> halves the stiffness ... this is an instance of a [[scaling law]] of whom you'll here a lot here
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* 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.
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</div>
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</div>
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= How do atoms work and what shape do they have ? =
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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.
  
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For a quick overview (like here) a detailed understanding of the inner workings of atoms is not (yet) necessary.
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While designing for this can be major PITA (ahem pretty difficult) like in electrical circuit design,
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For more detailed analysis (later) a detailed understanding is absolutely indispensable.
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it also potentially offers the possibility to archive extreme high efficiencies.
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If you want to dive down a bit further right away then check out the main article: "[[The nature and shape of atoms]]"
+
  
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The focus here will be mostly limited on the lightest simplest most common (and most [[Main Page|APM]] relevant) elements at the upper end of the periodic table.
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Also one can gain more control via deliberate introduction of discrete damping elements.
  
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== Tetrapodal arrangement of electron clouds ==
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= Everything is shaky =
  
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[[File:AE4h.svg|200px|thumb|right|Tetrapodal electron cloud arrangement (tech term: sp<sup>3</sup>) '''Note:''' This is still a simplified view. The orbitals are actually more bean shaped, overlapping and blurry. But depicting it more realistically would obfuscate the geometric arrangement too much.]]
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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'''
  
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In those most common elements the most common arrangement of the outer (and thus relevant) "electron clouds" (in molecules or crystals) is tetrapodal (tetrahedral) with four lobes (four==tetra). As depicted in blue here.
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* What happens when you let go of a building block?
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Note that the small lobes are part of the big ones on the opposing side respectively.
+
  
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A more technical term for "electron clouds" is "orbitals" specifically the ones depicted blue here are called "hybrid orbitals".
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Main article: "[[The heat-overpowers-gravity size-scale]]"
  
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* Orbitals filled with two electrons from the host atom (as depicted here) are called "lone pairs" and repel lone pairs from other atoms.
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Let's consider an somewhat unusual fall experiment. A small gripper let go of a building block. Simple? See if you answer right.
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* Orbitals filled with one electron from the host atom and one electron from a neighboring atoms merge together and are called bonding "molecular orbitals".
+
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* In case too many electrons are missing (sometimes the case with elements to the left of carbon in the periodic table) the geometric arrangement of electron clouds can change. Details elsewhere.
+
  
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The four orbitals in the tetropodal geometry do not lie in a common plane (they are not coplanar)
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Related: [[spiky needle grabbing]]
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In case one has just the right amount of electrons:
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* not too many - forming lone pairs
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* not too few - changing orbital arrangement
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... like in the case of carbon (and silicon) then the atoms can bond to other atoms in all four non coplanar directions and can form three dimensional crystal structures. Not just sheets or chains.
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The prime examples for tightly meshed 3D networks of that kind are diamond and silicon (silicon-the-crystal not silicon-the-element).
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This is one of the reasons why carbon is sometimes referred to as "king of elements".
+
  
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== Triangular arrangement of hybrid orbitals ==
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[[File:Fall-experiment-quiz-en.svg|thumb|center|480px|A fall experiment quiz to illustrate the quite unfamiliar mechanical behavior in the nanoscale.]]
  
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[[File:AE3h.svg|150px|thumb|right|Triangular electron cloud arrangement. (tech term: sp<sup>2</sup>) '''Note:''' the fourth orbital is not depicted!]]
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= Scaling laws =
  
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There are other possible electron cloud arrangements too.
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They describe what changes when one goes down the scale.
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The second most common one is triangular (as depicted here in blue).
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E.g. that magnetic motors become weak but electrostatic ones strong.
 +
More details can be found at the [[scaling laws|scaling laws main page]].
  
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The light elements have four outer shell orbitals but only three are depicted here, so one is obviously missing.
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= The prospective feel of gem-gum products =
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The missing/non-depicted fourth one sticks out vertically both up and down equally from the image-plane.
+
−
The fourth orbital has no small and big lobe like the three depicted hybrid orbitals have.
+
−
It is a fundamental orbital (a p-orbital - a raw solution from the [[Schrödinger equation|underlying math]]) with two lobes of exactly equal size.
+
  
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The three hybrid orbitals lie in the same plane and the fourth (the fundamental) orbital has no preference for facing upwards or downwards. Thus atoms that take on this triangular orbital arrangement cannot form three dimensional structures in a way like the atoms with tetrapodal structure. Instead they can only form two dimensional sheets.
+
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.
  
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Just like in the tetrapodal arrangement also in the triangular arrangement case carbon (and silicon) atoms have the ideal number of electrons to neither form lone pairs (repulsing other lone pairs) nor change orbital arrangement.
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= Related =
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Thus a prime example for sheets out of atoms in triangular orbital arrangement are sheets made out of carbon.
+
  
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In the simplest, that is fully planar, form this is called a graphene sheet.
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Provide means for an intuitive understanding seems to be
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Stacks of large graphene sheets form very hard single crystalline graphite.
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a good [[didactic approach]] for a wide [[target audience]].  
−
Normal pencil mine graphite is polycrystalline allowing the small sheet-flakes to slide over each other making it very soft.
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(Side-note: Larger chunks of single crystalline graphite do not occur naturally but can by synthesized today. It is called: HOPG)
+
  
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In a graphene sheet the fourth orbital (the non-hybridized fundamental p-orbital) different from the three triangularly arranged hybrid orbitals plays a very special role. Not only sticks it out both sides equally it also shares one bond in three directions simultaneously on each side. All those doublesided p-prbitals fuse together to one single giant (double sheeted) molecule orbital spanning over the whole sheet on both sides. This allows electrons to move freely (electric conductivity).
+
== In the book "Radical Abundance" ==
  
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Bending graphite sheets by various means can drastically (and usefully) change the electronic properties.
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In the book [[Radical Abundance]] the introduction tries to convey an intuitive feel for how things behave down at the nanoscale.
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From semi-conductivity to very high conductivity (much better than copper or silver).
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{{wikitodo|give a more precise reference}}
  
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The tech term for hybrid orbitals that assume the here describesd triangular shape is: sp<sup>2</sup>.
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== Richard Feynman ==
  
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Beside electronic property changes bending sp<sup>2</sup> sheets (graphite or other) also allows them to form three dimensional structures when the sheets locally can actually only be two dimensional.
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There are great recordings of the famous physicist and teacher Richard Feynmen about the importance:
 +
* of an intuitive understanding of things and
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* of looking at things from new perspectives.
  
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* Flat sheets must have all atoms arranged in hexagons.
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Main article: [[Richard Feynman]]
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* Flat sheets occur rolled up into tubular shapes ([[Nanotubes]] in general). Beside various diameters different rolling angles are possible (causing different eletronic properties).
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* Sheets can be bent convex (or concave depending on the onlooking side) by replacing some hexagons with pentagons, squares or even triangles ([[Buckyballs]] in general).
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* Sheets can be bent hyperbolic by replacing some hexagons with heptagons, octagons, ... (Foam like structures e.g. DLC)
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= Speeds of motion in nanorobotics =
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== Related ==
  
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Today it's general education that temperature is equivalent to the speed of motion of particles at the atomic scale.
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=== Getting a good intuition about atoms ===
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If you unfamiliar with this "thermal motion" also known as "brownian motion" I suggest you read up on this elsewhere (e.g. wikipedia) before continuing here.
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== The incredible rate things zap past their surroundings (just driven by temperature) ==
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* [[Intuitively understanding the size of an atom]]
 +
* [[The feel of atoms]]
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* [[The basics of atoms]]
 +
* [[The speed of atoms]] – [[The speed of nanorobotiocs]] and ...
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* ... 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]]
  
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Thermal motion at the nanoscale is pretty incredible. <br>
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For an intuitive understanding how energies, forces, and stiffness <br>
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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 size by our [[conceivable magnification factor|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 then those hair sized molecules zip around with more than half the speed of light.
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at the nanoscale compare to each other see: [[Energy, force, and stiffness]]
  
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But since those water molecules are densely packed they do not move in long straight lines.
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=== Getting a good intuition about thermal motions ===
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* In liquid phase (e.g. water) they move in twisty paths with curve radii of about their own size.
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* In one atmosphere gas phase (e.g. air) they move about 250 times their size (the mean free path length) before colliding and making a more or less U turn. In the 500,000 times scaled up model those U-turns are executed at near the speed of light every 2.5 centimeters (250 x 0.1mm).
+
  
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Note that molecules in a liquid or gas that are not bond to a crystal run apart quantum-blurrily quite quickly (more on that later).
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* [[The heat-overpowers-gravity size-scale]]
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So a "soup" of a superposition of all possible collision-histories is a better picture for fluids and gasses.
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* [[thermally skittering building blocks]]
 +
* [[thermally jumping building blocks]] – practically likely not happening except designed for – [[spiky needle grabbing]]
  
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== Assembly by mindlessly throwing parts together at ridiculous rates ==
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=== Averting false intuitions – things that may come unexpected ===
  
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Given this situation it becomes very obvious that in a liquid environment that is densely packed with other solvent molecules (e.g. water) solvated molecules meet a lot of other solvated molecules in a very short amount of time.
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* Why [[nanomechanics is barely mechanical quantummechanics]]
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Bigger more massive molecules like proteins ("puzzle piece molecules") move slower but collision rates are still very very high.
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* '''[[A better intuition for diamondoid nanomachinery than jelly]]'''
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* [[Misleading aspects in animations of diamondoid molecular machine elements]]
 +
* [[Soft-core macrorobots with hard-core nanomachinery]]
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* The [[unsupported rotating ring speed limit]]
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* [[Scaling law]]s
  
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This is why puzzle piece shaped proteins molecules in biological systems can "assemble themselves" into their intended products. Via their random collisions they just mindlessly try all possible places they could bond to in very very fast succession. It's mindless trying like having toddlers that do not yet grasp that cubes do not fit through round holes do the assembly job but since it's done so fast (like brute force computer algorithms) useful things can be assembled nonetheless.
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=== Truely intuitively understanding the size scales involved ===
  
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The technical term for this method of assembly is "self assembly" but here we'll call it "[[thermally driven assembly]]" which captures the meaning better. On the day to day macroscale this method of assembly is usually not applied for practical purposes due to its ridiculous slowness and requirement of parts fitting together like a sticky puzzle. Fully grasping the process how it happens at the nanoscale at an intuitive level may be impossible due to the vast number of trials until the final successful bonding reaction. {{todo|investigate better visualization methods}}
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* [[Maginification theme park]]
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There are beautiful CG videos of molecular biology that use fake motions mo make it comprehensible {{todo|add link}}.
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* [[Intuitively understanding the size of an atom]]
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* [[Distorted visualisation methods for convergent assembly]]
  
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== Use of thermally driven assembly to get away from thermally driven assembly ASAP ==
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=== An intuition about the possible consequences of gemstone metamaterial technology ===
  
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[[Thermally driven assembly]] is the predominant form of assembly in biological systems.
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* Understanding possible consequences of [[gem-gum technology]] via [[story scenarios]].
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[[Thermally driven assembly]] of increasingly arfificial molecules will be (and already is!!) a very useful tool for walking the initial steps of the path to advanced nanofactories.
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But as it turns out in an advanced nanofactory (the far term goal) it makes much more sense to actually constrain / suppress thermal vibrations and take care of the transport oneself in a fully controlled and less mindless fashion.
+
  
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The idea of working towards a point where we deny the help of thermal motion (shunning the teachings of nature) but doing assembly tightly controlled and guided instead has received harsh criticism in the past. It was and still is often misunderstood as a misunderstading of the real nature of the nanocosm.
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= External links =
  
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But there actually is '''an example where we already succeeded with the suppression of thermal noise.
 
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Nanoelectronics.''' In microchips we've already learned to suppress thermally caused electrical noise without even noticing it since it just gradually got more difficult.
 
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The two necessary requirements for thermal noise suppression are the same that we used to get away from analog technology namely:
 
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* error margins and
 
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* error correction
 
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Now we use mostly digital electronics.
 
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Given that electrons start to behave strongly quantum-mechanically in the nanoscale
 
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(quantum blurriness and thermal motion can often be treated in a common fashion) -- which stands is [[Nanomechanics is barely mechanical quantummechanics|in stark contrast to nanomechanical nanomachines]] -- this is even more of a feat. We where not forced to switch some sort of probabilistic electronics (whatever that would be). Since much less quantum mechanical in behavior advanced nanomechanical systems will have even less reason to work in a purely probabilistic fashion.
 
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== The smaller the more productive ==
 
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Main article: "[[Higher productivity of smaller machinery]]"
 
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While size goes down speed goes up.
 
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A good example in nature is the increasing wing flapping rate seen in birds and insects.
 
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By naively scaling down a current day 3D-printer by a factor of 500.000 (just for illustration - not a serious proposal) it becomes 500.000 times faster.
 
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A typically time for 3D printers to print parts that have about the mass of the printer itself is on the order of 10 hours. This shrinks down to just 0.72 seconds.
 
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Now a single shrunk down printer won't produce much but imagine the whole volume of the original non-shrunk printer filled up with shrunk down printers. This would then produce the macroscale printers own mass in less than a second.
 
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In a serious advanced nanofactory design the time to produce the production machinery's own mass can become
 
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even smaller due to better materials, lower friction, smaller size steps, to name a few reasons.
 
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'''For a good intuitive feel about the production rate imagine products shooting out like rifle bullets.'''
 
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I fact the time to produce production machinery's own mass can become so short that the products that can be produced at the nanoscale cannot be fed out fast enough at the [[macroscale]] anymore.
 
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Getting even remotely near there would require impractical levels of cooling.
 
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Solution: One humbly accepts not to get the full crazy level potential of nanoscale production machinery
 
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and is content with just more than practical levels of productivity.
 
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To do this one does not fill up the whole volume with productive nanosystems. One abandons the concept of clouds of [[molecular assembler]]s. Instead one integrates everything in a thin chip. A nanofactory.
 
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For details check the main article: [[Macroscale slowness bottleneck]]
 
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Even in the case when one really wants to push the limits (there's likely military interest here) its likely that a highly advanced fractal nanofactory that is a little thicker is the best solution.
 
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For a continuously running device the cooling facilities then are likely much bigger than the productive device itself. The production becomes highly inefficient and turns a lot of energy into heat.
 
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Still there is the [[fundamental specific acceleration limit]] which cannot be exceeded.
 
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This is the point where no known material would not break from the acceleration loads.
 
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== Motions in the far term goal of advanced nanofactories ==
 
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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 than the thermal motions (about at least a factor of 1000) but since every try is a hit (for all practical purposes) the production throughput can be the same or higher than the one of natural bio-systems that work with [[thermally driven assembly]].
 
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In rare occasions one might want to let go of molecules or [[crystolecule]]s in an advanced nanosystem.
 
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Thermal motion for bigger [[crystolecule]]s in a vacuum under gravity are statistically distributed throwing parabolas.
 
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Single molecules show significant quantum blurring when released.
 
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* [https://upload.wikimedia.org/wikipedia/commons/4/4d/Huellkurve_wurfparabel.svg Envelope of throwing trajectories with same speed]
 
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* [https://commons.wikimedia.org/wiki/File:Inclinedthrow.gif Throwing trajectories with various speed in same direction]
 
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= 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.
 
−
 
−
[[File:Fall-experiment-quiz-en.svg|thumb|center|480px|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|scaling laws main page]].
 
−
 
−
= The feel of AP Products =
 
−
 
−
AP products though robotic and gemstone like in the nanocosm are not necessarily cold hard and robot like to the human senses.
 
−
[[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 =
 
−
 
−
{{todo|Add the same info table as on VdW force page}} <br>
 
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['''Todo:''' Add table - make it visualizable for covalent bonds and VdW bonds] <br>
 
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['''Todo:''' show surface area thats VdW ashesion is energetically equivalent to one covalent bond - related: [[Form locking]]]
 
−
 
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* [[Connection method#Van der Waals locking]]
 
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* [[Van der Waals force]]
 
−
 
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= Further =
 
−
 
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* [[Periodic table of elements]]
 
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* acceleration limits
 
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* jumping building blocks
 
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* Why [[nanomechanics is barely mechanical quantummechanics]]
 
 
* '''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")]
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* [[Distorted visualisation methods for convergent assembly]]
 
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* [[Scaling law]]s
 
  
 
[[Category:General]]
 
[[Category:General]]

Latest revision as of 19:42, 18 October 2024

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

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