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author: aiju <[email protected]>
date: Mon Jun 15 12:27:27 EDT 2015
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+There's Plenty of Room at the Bottom
+
+An Invitation to Enter a New Field of Physics
+
+by Richard P. Feynman
+
+This transcript of the classic talk that Richard Feynman gave on December
+29th 1959 at the annual meeting of the American Physical Society at
+the California Institute of Technology (Caltech) was first published in
+Caltech Engineering and Science, Volume 23:5, February 1960, pp 22-36.
+
+__________________________________________________________________
+
+I imagine experimental physicists must often look with envy at men like
+Kamerlingh Onnes, who discovered a field like low temperature, which
+seems to be bottomless and in which one can go down and down. Such a
+man is then a leader and has some temporary monopoly in a scientific
+adventure. Percy Bridgman, in designing a way to obtain higher pressures,
+opened up another new field and was able to move into it and to lead
+us all along. The development of ever higher vacuum was a continuing
+development of the same kind.
+
+I would like to describe a field, in which little has been done, but in
+which an enormous amount can be done in principle. This field is not quite
+the same as the others in that it will not tell us much of fundamental
+physics (in the sense of, "What are the strange particles?") but it is
+more like solid-state physics in the sense that it might tell us much
+of great interest about the strange phenomena that occur in complex
+situations. Furthermore, a point that is most important is that it would
+have an enormous number of technical applications.
+
+What I want to talk about is the problem of manipulating and controlling
+things on a small scale.
+
+As soon as I mention this, people tell me about miniaturization, and how
+far it has progressed today. They tell me about electric motors that are
+the size of the nail on your small finger. And there is a device on the
+market, they tell me, by which you can write the Lord's Prayer on the
+head of a pin. But that's nothing; that's the most primitive, halting
+step in the direction I intend to discuss. It is a staggeringly small
+world that is below. In the year 2000, when they look back at this age,
+they will wonder why it was not until the year 1960 that anybody began
+seriously to move in this direction.
+
+Why cannot we write the entire 24 volumes of the Encyclopaedia Brittanica
+on the head of a pin?
+
+Let's see what would be involved. The head of a pin is a sixteenth of an
+inch across. If you magnify it by 25,000 diameters, the area of the head
+of the pin is then equal to the area of all the pages of the Encyclopaedia
+Brittanica. Therefore, all it is necessary to do is to reduce in size all
+the writing in the Encyclopaedia by 25,000 times. Is that possible? The
+resolving power of the eye is about 1/120 of an inch – that is roughly
+the diameter of one of the little dots on the fine half-tone reproductions
+in the Encyclopaedia. This, when you demagnify it by 25,000 times,
+is still 80 angstroms in diameter – 32 atoms across, in an ordinary
+metal. In other words, one of those dots still would contain in its area
+1,000 atoms. So, each dot can easily be adjusted in size as required by
+the photoengraving, and there is no question that there is enough room
+on the head of a pin to put all of the Encyclopaedia Brittanica.
+
+Furthermore, it can be read if it is so written. Let's imagine that
+it is written in raised letters of metal; that is, where the black is
+in the Encyclopedia, we have raised letters of metal that are actually
+1/25,000 of their ordinary size. How would we read it?
+
+If we had something written in such a way, we could read it using
+techniques in common use today. (They will undoubtedly find a better way
+when we do actually have it written, but to make my point conservatively
+I shall just take techniques we know today.) We would press the metal
+into a plastic material and make a mold of it, then peel the plastic off
+very carefully, evaporate silica into the plastic to get a very thin film,
+then shadow it by evaporating gold at an angle against the silica so that
+all the little letters will appear clearly, dissolve the plastic away from
+the silica film, and then look through it with an electron microscope!
+
+There is no question that if the thing were reduced by 25,000 times in
+the form of raised letters on the pin, it would be easy for us to read
+it today. Furthermore, there is no question that we would find it easy
+to make copies of the master; we would just need to press the same metal
+plate again into plastic and we would have another copy.
+
+How do we write small?
+
+The next question is: How do we write it? We have no standard technique
+to do this now. But let me argue that it is not as difficult as it first
+appears to be. We can reverse the lenses of the electron microscope in
+order to demagnify as well as magnify. A source of ions, sent through the
+microscope lenses in reverse, could be focused to a very small spot. We
+could write with that spot like we write in a TV cathode ray oscilloscope,
+by going across in lines, and having an adjustment which determines the
+amount of material which is going to be deposited as we scan in lines.
+
+This method might be very slow because of space charge limitations.
+There will be more rapid methods. We could first make, perhaps by
+some photo process, a screen which has holes in it in the form of the
+letters. Then we would strike an arc behind the holes and draw metallic
+ions through the holes; then we could again use our system of lenses and
+make a small image in the form of ions, which would deposit the metal
+on the pin.
+
+A simpler way might be this (though I am not sure it would work):
+We take light and, through an optical microscope running backwards,
+we focus it onto a very small photoelectric screen. Then electrons
+come away from the screen where the light is shining. These electrons
+are focused down in size by the electron microscope lenses to impinge
+directly upon the surface of the metal. Will such a beam etch away the
+metal if it is run long enough? I don't know. If it doesn't work for a
+metal surface, it must be possible to find some surface with which to
+coat the original pin so that, where the electrons bombard, a change is
+made which we could recognize later.
+
+There is no intensity problem in these devices not what you are used
+to in magnification, where you have to take a few electrons and spread
+them over a bigger and bigger screen; it is just the opposite. The light
+which we get from a page is concentrated onto a very small area so it
+is very intense. The few electrons which come from the photoelectric
+screen are demagnified down to a very tiny area so that, again, they
+are very intense. I don't know why this hasn't been done yet!
+
+That's the Encyclopaedia Brittanica on the head of a pin, but let's
+consider all the books in the world. The Library of Congress has
+approximately 9 million volumes; the British Museum Library has 5 million
+volumes; there are also 5 million volumes in the National Library in
+France. Undoubtedly there are duplications, so let us say that there
+are some 24 million volumes of interest in the world.
+
+What would happen if I print all this down at the scale we have been
+discussing? How much space would it take? It would take, of course, the
+area of about a million pinheads because, instead of there being just
+the 24 volumes of the Encyclopaedia, there are 24 million volumes. The
+million pinheads can be put in a square of a thousand pins on a side, or
+an area of about 3 square yards. That is to say, the silica replica with
+the paper-thin backing of plastic, with which we have made the copies,
+with all this information, is on an area of approximately the size of 35
+pages of the Encyclopaedia. That is about half as many pages as there are
+in this magazine. All of the information which all of mankind has ever
+recorded in books can be carried around in a pamphlet in your hand –
+and not written in code, but as a simple reproduction of the original
+pictures, engravings, and everything else on a small scale without loss
+of resolution.
+
+What would our librarian at Caltech say, as she runs all over from one
+building to another, if I tell her that, ten years from now, all of the
+information that she is struggling to keep track of – 120,000 volumes,
+stacked from the floor to the ceiling, drawers full of cards, storage
+rooms full of the older books – can be kept on just one library card!
+When the University of Brazil, for example, finds that their library is
+burned, we can send them a copy of every book in our library by striking
+off a copy from the master plate in a few hours and mailing it in an
+envelope no bigger or heavier than any other ordinary air mail letter.
+
+Now, the name of this talk is "There is Plenty of Room at the Bottom"
+– not just "There is Room at the Bottom." What I have demonstrated
+is that there is room – that you can decrease the size of things in a
+practical way. I now want to show that there is plenty of room. I will
+not now discuss how we are going to do it, but only what is possible
+in principle – in other words, what is possible according to the laws
+of physics. I am not inventing anti-gravity, which is possible someday
+only if the laws are not what we think. I am telling you what could be
+done if the laws are what we think; we are not doing it simply because
+we haven't yet gotten around to it.
+
+Information on a small scale
+
+Suppose that, instead of trying to reproduce the pictures and all the
+information directly in its present form, we write only the information
+content in a code of dots and dashes, or something like that, to represent
+the various letters. Each letter represents six or seven "bits" of
+information; that is, you need only about six or seven dots or dashes
+for each letter. Now, instead of writing everything, as I did before,
+on the surface of the head of a pin, I am going to use the interior of
+the material as well.
+
+Let us represent a dot by a small spot of one metal, the next dash by an
+adjacent spot of another metal, and so on. Suppose, to be conservative,
+that a bit of information is going to require a little cube of atoms 5
+x 5 x 5 – that is 125 atoms. Perhaps we need a hundred and some odd
+atoms to make sure that the information is not lost through diffusion,
+or through some other process.
+
+I have estimated how many letters there are in the Encyclopaedia,
+and I have assumed that each of my 24 million books is as big as an
+Encyclopaedia volume, and have calculated, then, how many bits of
+information there are (10^15). For each bit I allow 100 atoms. And it
+turns out that all of the information that man has carefully accumulated
+in all the books in the world can be written in this form in a cube
+of material one two-hundredth of an inch wide – which is the barest
+piece of dust that can be made out by the human eye. So there is plenty
+of room at the bottom! Don't tell me about microfilm!
+
+This fact – that enormous amounts of information can be carried in an
+exceedingly small space – is, of course, well known to the biologists,
+and resolves the mystery which existed before we understood all this
+clearly, of how it could be that, in the tiniest cell, all of the
+information for the organization of a complex creature such as ourselves
+can be stored. All this information – whether we have brown eyes,
+or whether we think at all, or that in the embryo the jawbone should
+first develop with a little hole in the side so that later a nerve can
+grow through it – all this information is contained in a very tiny
+fraction of the cell in the form of long-chain DNA molecules in which
+approximately 50 atoms are used for one bit of information about the cell.
+
+Better electron microscopes
+
+If I have written in a code, with 5 x 5 x 5 atoms to a bit, the question
+is: How could I read it today? The electron microscope is not quite good
+enough, with the greatest care and effort, it can only resolve about 10
+angstroms. I would like to try and impress upon you while I am talking
+about all of these things on a small scale, the importance of improving
+the electron microscope by a hundred times. It is not impossible; it is
+not against the laws of diffraction of the electron. The wave length of
+the electron in such a microscope is only 1/20 of an angstrom. So it
+should be possible to see the individual atoms. What good would it be
+to see individual atoms distinctly?
+
+We have friends in other fields – in biology, for instance. We
+physicists often look at them and say, "You know the reason you fellows
+are making so little progress?" (Actually I don't know any field where
+they are making more rapid progress than they are in biology today.)
+"You should use more mathematics, like we do." They could answer us –
+but they're polite, so I'll answer for them: "What you should do in order
+for us to make more rapid progress is to make the electron microscope
+100 times better."
+
+What are the most central and fundamental problems of biology today?
+They are questions like: What is the sequence of bases in the DNA? What
+happens when you have a mutation? How is the base order in the DNA
+connected to the order of amino acids in the protein? What is the
+structure of the RNA; is it single-chain or double-chain, and how is it
+related in its order of bases to the DNA? What is the organization of
+the microsomes? How are proteins synthesized? Where does the RNA go?
+How does it sit? Where do the proteins sit? Where do the amino acids
+go in? In photosynthesis, where is the chlorophyll; how is it arranged;
+where are the carotenoids involved in this thing? What is the system of
+the conversion of light into chemical energy?
+
+It is very easy to answer many of these fundamental biological questions;
+you just look at the thing! You will see the order of bases in the
+chain; you will see the structure of the microsome. Unfortunately, the
+present microscope sees at a scale which is just a bit too crude. Make
+the microscope one hundred times more powerful, and many problems of
+biology would be made very much easier. I exaggerate, of course, but
+the biologists would surely be very thankful to you – and they would
+prefer that to the criticism that they should use more mathematics.
+
+The theory of chemical processes today is based on theoretical physics.
+In this sense, physics supplies the foundation of chemistry. But
+chemistry also has analysis. If you have a strange substance and you
+want to know what it is, you go through a long and complicated process
+of chemical analysis. You can analyze almost anything today, so I am a
+little late with my idea. But if the physicists wanted to, they could
+also dig under the chemists in the problem of chemical analysis. It would
+be very easy to make an analysis of any complicated chemical substance;
+all one would have to do would be to look at it and see where the atoms
+are. The only trouble is that the electron microscope is one hundred times
+too poor. (Later, I would like to ask the question: Can the physicists do
+something about the third problem of chemistry – namely, synthesis? Is
+there a physical way to synthesize any chemical substance?
+
+The reason the electron microscope is so poor is that the f- value of the
+lenses is only 1 part to 1,000; you don't have a big enough numerical
+aperture. And I know that there are theorems which prove that it is
+impossible, with axially symmetrical stationary field lenses, to produce
+an f-value any bigger than so and so; and therefore the resolving power
+at the present time is at its theoretical maximum. But in every theorem
+there are assumptions. Why must the field be axially symmetrical? Why must
+the field be stationary? Can't we have pulsed electron beams in fields
+moving up along with the electrons? Must the field be symmetrical? I put
+this out as a challenge: Is there no way to make the electron microscope
+more powerful?
+
+The marvelous biological system
+
+The biological example of writing information on a small scale has
+inspired me to think of something that should be possible. Biology is not
+simply writing information; it is doing something about it. A biological
+system can be exceedingly small. Many of the cells are very tiny, but they
+are very active; they manufacture various substances; they walk around;
+they wiggle; and they do all kinds of marvelous things – all on a very
+small scale. Also, they store information. Consider the possibility that
+we too can make a thing very small which does what we want – that we
+can manufacture an object that maneuvers at that level!
+
+There may even be an economic point to this business of making things very
+small. Let me remind you of some of the problems of computing machines. In
+computers we have to store an enormous amount of information. The kind
+of writing that I was mentioning before, in which I had everything down
+as a distribution of metal, is permanent. Much more interesting to a
+computer is a way of writing, erasing, and writing something else. (This
+is usually because we don't want to waste the material on which we have
+just written. Yet if we could write it in a very small space, it wouldn't
+make any difference; it could just be thrown away after it was read. It
+doesn't cost very much for the material).
+
+Miniaturizing the computer
+
+I don't know how to do this on a small scale in a practical way, but I do
+know that computing machines are very large; they fill rooms. Why can't
+we make them very small, make them of little wires, little elements –
+and by little, I mean little. For instance, the wires should be 10 or 100
+atoms in diameter, and the circuits should be a few thousand angstroms
+across. Everybody who has analyzed the logical theory of computers has
+come to the conclusion that the possibilities of computers are very
+interesting – if they could be made to be more complicated by several
+orders of magnitude. If they had millions of times as many elements,
+they could make judgments. They would have time to calculate what is
+the best way to make the calculation that they are about to make. They
+could select the method of analysis which, from their experience, is
+better than the one that we would give to them. And in many other ways,
+they would have new qualitative features.
+
+If I look at your face I immediately recognize that I have seen it
+before. (Actually, my friends will say I have chosen an unfortunate
+example here for the subject of this illustration. At least I recognize
+that it is a man and not an apple.) Yet there is no machine which,
+with that speed, can take a picture of a face and say even that it is
+a man; and much less that it is the same man that you showed it before
+– unless it is exactly the same picture. If the face is changed; if
+I am closer to the face; if I am further from the face; if the light
+changes – I recognize it anyway. Now, this little computer I carry
+in my head is easily able to do that. The computers that we build are
+not able to do that. The number of elements in this bone box of mine
+are enormously greater than the number of elements in our "wonderful"
+computers. But our mechanical computers are too big; the elements in
+this box are microscopic. I want to make some that are sub-microscopic.
+
+If we wanted to make a computer that had all these marvelous extra
+qualitative abilities, we would have to make it, perhaps, the size of
+the Pentagon. This has several disadvantages. First, it requires too
+much material; there may not be enough germanium in the world for all
+the transistors which would have to be put into this enormous thing.
+There is also the problem of heat generation and power consumption; TVA
+would be needed to run the computer. But an even more practical difficulty
+is that the computer would be limited to a certain speed. Because of its
+large size, there is finite time required to get the information from one
+place to another. The information cannot go any faster than the speed of
+light – so, ultimately, when our computers get faster and faster and
+more and more elaborate, we will have to make them smaller and smaller.
+
+But there is plenty of room to make them smaller. There is nothing that
+I can see in the physical laws that says the computer elements cannot
+be made enormously smaller than they are now. In fact, there may be
+certain advantages.
+
+Miniaturization by evaporation
+
+How can we make such a device? What kind of manufacturing processes
+would we use? One possibility we might consider, since we have talked
+about writing by putting atoms down in a certain arrangement, would
+be to evaporate the material, then evaporate the insulator next to it.
+Then, for the next layer, evaporate another position of a wire, another
+insulator, and so on. So, you simply evaporate until you have a block
+of stuff which has the elements – coils and condensers, transistors
+and so on – of exceedingly fine dimensions.
+
+But I would like to discuss, just for amusement, that there are other
+possibilities. Why can't we manufacture these small computers somewhat
+like we manufacture the big ones? Why can't we drill holes, cut things,
+solder things, stamp things out, mold different shapes all at an
+infinitesimal level? What are the limitations as to how small a thing
+has to be before you can no longer mold it? How many times when you are
+working on something frustratingly tiny like your wife's wrist watch,
+have you said to yourself, "If I could only train an ant to do this!"
+What I would like to suggest is the possibility of training an ant to
+train a mite to do this. What are the possibilities of small but movable
+machines? They may or may not be useful, but they surely would be fun
+to make.
+
+Consider any machine – for example, an automobile – and ask about
+the problems of making an infinitesimal machine like it. Suppose, in the
+particular design of the automobile, we need a certain precision of the
+parts; we need an accuracy, let's suppose, of 4/10,000 of an inch. If
+things are more inaccurate than that in the shape of the cylinder and
+so on, it isn't going to work very well. If I make the thing too small,
+I have to worry about the size of the atoms; I can't make a circle out of
+"balls" so to speak, if the circle is too small. So, if I make the error,
+corresponding to 4/10,000 of an inch, correspond to an error of 10 atoms,
+it turns out that I can reduce the dimensions of an automobile 4,000
+times, approximately – so that it is 1 mm. across. Obviously, if you
+redesign the car so that it would work with a much larger tolerance,
+which is not at all impossible, then you could make a much smaller device.
+
+It is interesting to consider what the problems are in such small
+machines. Firstly, with parts stressed to the same degree, the forces go
+as the area you are reducing, so that things like weight and inertia are
+of relatively no importance. The strength of material, in other words,
+is very much greater in proportion. The stresses and expansion of the
+flywheel from centrifugal force, for example, would be the same proportion
+only if the rotational speed is increased in the same proportion as
+we decrease the size. On the other hand, the metals that we use have a
+grain structure, and this would be very annoying at small scale because
+the material is not homogeneous. Plastics and glass and things of this
+amorphous nature are very much more homogeneous, and so we would have
+to make our machines out of such materials.
+
+There are problems associated with the electrical part of the system –
+with the copper wires and the magnetic parts. The magnetic properties
+on a very small scale are not the same as on a large scale; there is the
+"domain" problem involved. A big magnet made of millions of domains can
+only be made on a small scale with one domain. The electrical equipment
+won't simply be scaled down; it has to be redesigned. But I can see no
+reason why it can't be redesigned to work again.
+
+Problems of lubrication
+
+Lubrication involves some interesting points. The effective viscosity of
+oil would be higher and higher in proportion as we went down (and if we
+increase the speed as much as we can). If we don't increase the speed so
+much, and change from oil to kerosene or some other fluid, the problem is
+not so bad. But actually we may not have to lubricate at all! We have a
+lot of extra force. Let the bearings run dry; they won't run hot because
+the heat escapes away from such a small device very, very rapidly.
+
+This rapid heat loss would prevent the gasoline from exploding, so an
+internal combustion engine is impossible. Other chemical reactions,
+liberating energy when cold, can be used. Probably an external supply
+of electrical power would be most convenient for such small machines.
+
+What would be the utility of such machines? Who knows? Of course, a small
+automobile would only be useful for the mites to drive around in, and I
+suppose our Christian interests don't go that far. However, we did note
+the possibility of the manufacture of small elements for computers in
+completely automatic factories, containing lathes and other machine tools
+at the very small level. The small lathe would not have to be exactly like
+our big lathe. I leave to your imagination the improvement of the design
+to take full advantage of the properties of things on a small scale, and
+in such a way that the fully automatic aspect would be easiest to manage.
+
+A friend of mine (Albert R. Hibbs) suggests a very interesting possibility
+for relatively small machines. He says that, although it is a very
+wild idea, it would be interesting in surgery if you could swallow the
+surgeon. You put the mechanical surgeon inside the blood vessel and it
+goes into the heart and "looks" around. (Of course the information has
+to be fed out.) It finds out which valve is the faulty one and takes a
+little knife and slices it out. Other small machines might be permanently
+incorporated in the body to assist some inadequately-functioning organ.
+
+Now comes the interesting question: How do we make such a tiny
+mechanism? I leave that to you. However, let me suggest one weird
+possibility. You know, in the atomic energy plants they have materials
+and machines that they can't handle directly because they have become
+radioactive. To unscrew nuts and put on bolts and so on, they have a set
+of master and slave hands, so that by operating a set of levers here,
+you control the "hands" there, and can turn them this way and that so
+you can handle things quite nicely.
+
+Most of these devices are actually made rather simply, in that there is
+a particular cable, like a marionette string, that goes directly from
+the controls to the "hands." But, of course, things also have been made
+using servo motors, so that the connection between the one thing and the
+other is electrical rather than mechanical. When you turn the levers,
+they turn a servo motor, and it changes the electrical currents in the
+wires, which repositions a motor at the other end.
+
+Now, I want to build much the same device – a master-slave system
+which operates electrically. But I want the slaves to be made especially
+carefully by modern large-scale machinists so that they are one-fourth
+the scale of the "hands" that you ordinarily maneuver. So you have
+a scheme by which you can do things at one- quarter scale anyway –
+the little servo motors with little hands play with little nuts and
+bolts; they drill little holes; they are four times smaller. Aha! So
+I manufacture a quarter-size lathe; I manufacture quarter-size tools;
+and I make, at the one-quarter scale, still another set of hands again
+relatively one-quarter size! This is one-sixteenth size, from my point of
+view. And after I finish doing this I wire directly from my large-scale
+system, through transformers perhaps, to the one-sixteenth-size servo
+motors. Thus I can now manipulate the one-sixteenth size hands.
+
+Well, you get the principle from there on. It is rather a difficult
+program, but it is a possibility. You might say that one can go much
+farther in one step than from one to four. Of course, this has all to be
+designed very carefully and it is not necessary simply to make it like
+hands. If you thought of it very carefully, you could probably arrive
+at a much better system for doing such things.
+
+If you work through a pantograph, even today, you can get much more
+than a factor of four in even one step. But you can't work directly
+through a pantograph which makes a smaller pantograph which then makes
+a smaller pantograph – because of the looseness of the holes and the
+irregularities of construction. The end of the pantograph wiggles with
+a relatively greater irregularity than the irregularity with which you
+move your hands. In going down this scale, I would find the end of the
+pantograph on the end of the pantograph on the end of the pantograph
+shaking so badly that it wasn't doing anything sensible at all.
+
+At each stage, it is necessary to improve the precision of the
+apparatus. If, for instance, having made a small lathe with a pantograph,
+we find its lead screw irregular – more irregular than the large-scale
+one – we could lap the lead screw against breakable nuts that you
+can reverse in the usual way back and forth until this lead screw is,
+at its scale, as accurate as our original lead screws, at our scale.
+
+We can make flats by rubbing unflat surfaces in triplicates together
+– in three pairs – and the flats then become flatter than the thing
+you started with. Thus, it is not impossible to improve precision on
+a small scale by the correct operations. So, when we build this stuff,
+it is necessary at each step to improve the accuracy of the equipment
+by working for awhile down there, making accurate lead screws, Johansen
+blocks, and all the other materials which we use in accurate machine
+work at the higher level. We have to stop at each level and manufacture
+all the stuff to go to the next level – a very long and very difficult
+program. Perhaps you can figure a better way than that to get down to
+small scale more rapidly.
+
+Yet, after all this, you have just got one little baby lathe four
+thousand times smaller than usual. But we were thinking of making an
+enormous computer, which we were going to build by drilling holes on
+this lathe to make little washers for the computer. How many washers
+can you manufacture on this one lathe?
+
+A hundred tiny hands
+
+When I make my first set of slave "hands" at one-fourth scale, I am
+going to make ten sets. I make ten sets of "hands," and I wire them to
+my original levers so they each do exactly the same thing at the same
+time in parallel. Now, when I am making my new devices one-quarter again
+as small, I let each one manufacture ten copies, so that I would have
+a hundred "hands" at the 1/16th size.
+
+Where am I going to put the million lathes that I am going to have? Why,
+there is nothing to it; the volume is much less than that of even one
+full-scale lathe. For instance, if I made a billion little lathes, each
+1/4000 of the scale of a regular lathe, there are plenty of materials
+and space available because in the billion little ones there is less
+than 2 percent of the materials in one big lathe.
+
+It doesn't cost anything for materials, you see. So I want to build a
+billion tiny factories, models of each other, which are manufacturing
+simultaneously, drilling holes, stamping parts, and so on.
+
+As we go down in size, there are a number of interesting problems that
+arise. All things do not simply scale down in proportion. There is the
+problem that materials stick together by the molecular (Van der Waals)
+attractions. It would be like this: After you have made a part and
+you unscrew the nut from a bolt, it isn't going to fall down because
+the gravity isn't appreciable; it would even be hard to get it off the
+bolt. It would be like those old movies of a man with his hands full of
+molasses, trying to get rid of a glass of water. There will be several
+problems of this nature that we will have to be ready to design for.
+
+Rearranging the atoms
+
+But I am not afraid to consider the final question as to whether,
+ultimately – in the great future – we can arrange the atoms the
+way we want; the very atoms, all the way down! What would happen if we
+could arrange the atoms one by one the way we want them (within reason,
+of course; you can't put them so that they are chemically unstable,
+for example).
+
+Up to now, we have been content to dig in the ground to find minerals.
+We heat them and we do things on a large scale with them, and we hope
+to get a pure substance with just so much impurity, and so on. But we
+must always accept some atomic arrangement that nature gives us. We
+haven't got anything, say, with a "checkerboard" arrangement, with the
+impurity atoms exactly arranged 1,000 angstroms apart, or in some other
+particular pattern.
+
+What could we do with layered structures with just the right layers?
+What would the properties of materials be if we could really arrange the
+atoms the way we want them? They would be very interesting to investigate
+theoretically. I can't see exactly what would happen, but I can hardly
+doubt that when we have some control of the arrangement of things on a
+small scale we will get an enormously greater range of possible properties
+that substances can have, and of different things that we can do.
+
+Consider, for example, a piece of material in which we make little
+coils and condensers (or their solid state analogs) 1,000 or 10,000
+angstroms in a circuit, one right next to the other, over a large area,
+with little antennas sticking out at the other end – a whole series
+of circuits. Is it possible, for example, to emit light from a whole
+set of antennas, like we emit radio waves from an organized set of
+antennas to beam the radio programs to Europe? The same thing would be
+to beam the light out in a definite direction with very high intensity.
+(Perhaps such a beam is not very useful technically or economically.)
+
+I have thought about some of the problems of building electric circuits
+on a small scale, and the problem of resistance is serious. If you build
+a corresponding circuit on a small scale, its natural frequency goes up,
+since the wave length goes down as the scale; but the skin depth only
+decreases with the square root of the scale ratio, and so resistive
+problems are of increasing difficulty. Possibly we can beat resistance
+through the use of superconductivity if the frequency is not too high,
+or by other tricks.
+
+Atoms in a small world
+
+When we get to the very, very small world – say circuits of seven
+atoms – we have a lot of new things that would happen that represent
+completely new opportunities for design. Atoms on a small scale behave
+like nothing on a large scale, for they satisfy the laws of quantum
+mechanics. So, as we go down and fiddle around with the atoms down
+there, we are working with different laws, and we can expect to do
+different things. We can manufacture in different ways. We can use, not
+just circuits, but some system involving the quantized energy levels,
+or the interactions of quantized spins, etc.
+
+Another thing we will notice is that, if we go down far enough, all of our
+devices can be mass produced so that they are absolutely perfect copies
+of one another. We cannot build two large machines so that the dimensions
+are exactly the same. But if your machine is only 100 atoms high, you
+only have to get it correct to one-half of one percent to make sure the
+other machine is exactly the same size – namely, 100 atoms high!
+
+At the atomic level, we have new kinds of forces and new kinds of
+possibilities, new kinds of effects. The problems of manufacture and
+reproduction of materials will be quite different. I am, as I said,
+inspired by the biological phenomena in which chemical forces are used
+in a repetitious fashion to produce all kinds of weird effects (one of
+which is the author).
+
+The principles of physics, as far as I can see, do not speak against the
+possibility of maneuvering things atom by atom. It is not an attempt
+to violate any laws; it is something, in principle, that can be done;
+but in practice, it has not been done because we are too big.
+
+Ultimately, we can do chemical synthesis. A chemist comes to us and says,
+"Look, I want a molecule that has the atoms arranged thus and so; make
+me that molecule." The chemist does a mysterious thing when he wants to
+make a molecule. He sees that it has got that ring, so he mixes this
+and that, and he shakes it, and he fiddles around. And, at the end of
+a difficult process, he usually does succeed in synthesizing what he
+wants. By the time I get my devices working, so that we can do it by
+physics, he will have figured out how to synthesize absolutely anything,
+so that this will really be useless.
+
+But it is interesting that it would be, in principle, possible (I think)
+for a physicist to synthesize any chemical substance that the chemist
+writes down. Give the orders and the physicist synthesizes it. How? Put
+the atoms down where the chemist says, and so you make the substance. The
+problems of chemistry and biology can be greatly helped if our ability to
+see what we are doing, and to do things on an atomic level, is ultimately
+developed – a development which I think cannot be avoided.
+
+Now, you might say, "Who should do this and why should they do it?"
+Well, I pointed out a few of the economic applications, but I know that
+the reason that you would do it might be just for fun. But have some
+fun! Let's have a competition between laboratories. Let one laboratory
+make a tiny motor which it sends to another lab which sends it back with
+a thing that fits inside the shaft of the first motor.
+
+High school competition
+
+Just for the fun of it, and in order to get kids interested in this field,
+I would propose that someone who has some contact with the high schools
+think of making some kind of high school competition. After all, we
+haven't even started in this field, and even the kids can write smaller
+than has ever been written before. They could have competition in high
+schools. The Los Angeles high school could send a pin to the Venice
+high school on which it says, "How's this?" They get the pin back,
+and in the dot of the 'i' it says, "Not so hot."
+
+Perhaps this doesn't excite you to do it, and only economics will do
+so. Then I want to do something; but I can't do it at the present moment,
+because I haven't prepared the ground. It is my intention to offer a
+prize of $1,000 to the first guy who can take the information on the
+page of a book and put it on an area 1/25,000 smaller in linear scale
+in such manner that it can be read by an electron microscope.
+
+And I want to offer another prize – if I can figure out how to phrase
+it so that I don't get into a mess of arguments about definitions – of
+another $1,000 to the first guy who makes an operating electric motor –
+a rotating electric motor which can be controlled from the outside and,
+not counting the lead-in wires, is only 1/64 inch cube.
+
+I do not expect that such prizes will have to wait very long for
+claimants.
+