User:Thermochap~enwikibooks/Sandbox

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Schematic of longitudinal and transverse distances and resolutions.

This is a page about size-scale awareness: awareness of how the world changes according to the size scale of your perspective. For example, large objects like the earth might be more sensitive to tidal forces than we are, while small objects like a molecule might be more likely to notice the strange effects of quantized angular momentum.

This subject is relevant because everyday life challenges us, along with the cells of which we are made, to inform our behaviors simultaneously to processes on size scales from nano to macro and beyond[1].

This is joint-editing space. Feel free to change, remove, add, and/or comment on anything you like, and also to put this page on your watchlist. As interest expands we'll move this discussion to other platforms and let you know about them here. For example, another instance of this discussion is active for those with a University of Missouri at Saint Louis single sign-on ID on the campus' internal mediawiki site. One might expect these offspring pages to diverge evolutionarily over time.

Introduction[edit | edit source]

Nanotechnology application schematic.

One frontier that everyone has access to is "the land of the small" in their own backyard. Increasingly powerful and accessible tools are opening the door to nanoworld adventurers. These tools can give students access to a world which is their very own, and where nature behaves in ways that are sometimes amazingly familiar and sometimes amazingly strange.

Where else would one find worlds where for example

  • inertia goes unnoticed,
  • walking on the ceiling is easy,
  • only motors with opposing axles actually work, and
  • stationary objects look blurrier than moving ones?

Moreover, such small explorations are relevant to present/future invention and job opportunities in science, engineering, medicine, criminology, biology, chemistry, electronics, and space science, as well as to our lives and the lives of those around us.

The links on this page are designed to collect ideas, for teachers and students, on putting these newfound tools to use as early as is possible and appropriate in the educational process.

Size effects[edit | edit source]

Mass versus size for various objects. 1[Dalton] ~ 1.66[yoctogram].

Effects that might visit you in everyday life[edit | edit source]

  • Thick-cut french fries absorb some oil, but thin-cut fries (because of their larger surface to volume ratio) may absorb much more. French-fry cutters at McDonald's have been made out of the same hard maraging steel that was used for the lunar rover's axle, because oil uptake is also an issue for the vendors. Where else is this effect important?
    • Sauce absorption by angel hair versus regular pasta.
    • Time to cook a potato versus the size of the pieces.
    • What else?
  • Large objects fall quickly, feathers fall more slowly, but particles smaller than 0.1 micron may never make it to the ground ‘cause of molecule impacts. Where else is this effect important?
  • Iron roofs don’t burn, steel wool burns reluctantly, but nano-iron may oxidize so fast that it catches things around it on fire when you turn on the light! Where else is this effect important?
  • Ferrofluids act like liquids 'til a magnet walks by and they turn into giant leaches with spikes on their back. What causes this "Terminator 2" type of effect?
  • Ballet dancers can be spun on point (it would seem) as slowly as they like, but not so with a virus particle. Why not?
  • What else?

Related questions[edit | edit source]

  • How do you tell when processes on small scales are involved in an experience?
  • How can you guess what effect size might have on e.g.
    • making protein spheres “taste” like rich and creamy fat,
    • making a thin film change color,
    • making a rope stronger,
    • making catalyst particles more effective,
    • keeping particles from settling out of air or water, or
    • making a sno-cone more likely to give you an “ice-cream headache”.
  • How to communicate an awareness of possibilities (e.g. even some of the simplest nanoscale devices have not yet been invented) and limits of our current tools for interacting with things on small size scales.

One's world according to size[edit | edit source]

Size effects cartoon. Click for more.

Macroworld[edit | edit source]

  • Tides and Coriolis are weak.
  • Gravity and inertia rule.
  • Electrostatics distract.
  • Touch is extra.
  • Terminal velocity is high.
  • Heat signals molecule motion.
  • What else?

Microworld[edit | edit source]

  • Forget tides and Coriolis.
  • Gravity and inertia are weak.
  • Electrostatics is scary.
  • Touch is manageable[2].
  • Terminal velocity is slow.
  • Brownian motion jostles.
  • What else?

Nanoworld[edit | edit source]

  • Touch is extreme.
  • Colloids don't settle.
  • Heat careens and jiggles.
  • Most atoms near surface.
  • Energies are quantized.
  • Electrons are fuzzy.
  • Slow spins disallowed.
  • Measurements alter.
  • What else?

Size range table[edit | edit source]

The shift in emphasis on various processes depending on the size-scale of one's world.
Effect\Size-Range MacroWorld MicroWorld NanoWorld
Tides & Coriolis Weak Negligible What's that?
Gravity & inertia Important Weak Negligible
Electrostatics Distracting Scary Off the charts
Touch Extra Manageable[2] Extreme
Terminal velocity High Slow Nearly zero
Heat/Brownian motion Signals random motion Jostles Careens & jiggles
Atoms near surface Few Many Most
Energies Allowed in bands Odd states are important Discrete values only
Slow spins No limit Slow in steps Disallowed
Electrons Shocking Polarizing Fuzzy
Measurements Possible? Intrusive Perturbing

Some useful numbers[edit | edit source]

Useful numbers for equidimensional (e.g. spherical) solid or liquid objects on selected size scales.
Name of scale Minimum
diameter		 Min. volume
in [Å3]		 Number of atoms at
7×1022 [atoms/cc]		 Min. surface
area in [Å2]		 # surface atoms at
1015 [atoms/cm2]		 Max. fraction of
atoms on surface		 Example
Milliworld-2 1[cm]=108[Å] (π/6)×1024 30×1021 + π×1016 3×1015 + 0.0000001 sugar cube
Milliworld-1 1[mm]=107[Å] (π/6)×1021 30 quintillion + π×1014 30 trillion + 0.000001 flea
Microworld-3 100[μm]=106[Å] (π/6)×1018 30 quadrillion + π×1012 300 billion + 0.00001 sand grain
Microworld-2 10[μm]=105[Å] (π/6)×1015 30 trillion + π×1010 3 billion + 0.0001 pollen
Microworld-1 1[μm]=104[Å] (π/6)×1012 30 billion + π×108 30 million + 0.001 cell
Nanoworld-3 100[nm]=1000[Å] (π/6)×109 30 million + π×106 300 thousand + 0.01 organelle
Nanoworld-2 10[nm]=100[Å] (π/6)×106 30 thousand + π×104 3 thousand + 0.1 virus
Nanoworld-1 1[nm]=10[Å] (π/6)×103 30 + π×102 30 + 1 buckyball
Picoworld-3 1[Ångström] (π/6) 1 + π 1 + 1 atom

In addition to major size differences between nanoworld objects at opposite ends of the thirty to 30-billion atom continuum, there are also important practical differences. For example, Nanoworld-1 and Nanoworld-2 objects may see the walls of a blood vessel as porous and therefore in medical applications not be possible to deliver from point A to point B using the circulatory system alone. Hence packages for intravenous delivery are often designed to have sizes in the larger Nanoworld-3 (30 million to 30 billion atom) range.

On the other hand, solid objects containing fewer than 3 billion atoms may be more appropriate for ejection into the interstellar medium by radiation pressure from the sun so they can overcome both Poynting Robertson drag as well as the sun's gravitational pull. A gaggle of such tiny "spaceships" (like those our carbon atoms came here in) might fan out on their own across the Milky Way in under a billion years, although what they do beyond that (if anything) will depend on the details of their structure.

The figure below shows that for solid and liquid phases of wide-ranging density in [grams/cc] that the number η of [atoms per cubic centimeter] is remarkably constant. A typical value is η = 7×1022 [atoms/cc], which translates into a typical distance of η-1/3 ~ 2.4 [Å] between atoms with 3D kissing-number 12. Some atoms, like carbon, accomodate directionally-correlated (e.g. tetrahedral) bond lengths which are closer to 1.5 [Å]. If such directional bonds don't shorten enough to compensate for fewer nearest neighbors, the solid floats on the liquid which is why SiO2 continents don't sink and why fresh-water fish can avoid freezing in the winter[3]. Thank goodness!

Atomic number densities for the elements (solids and liquids in the top row) at standard temperature 25[oC] and pressure 101.325[kPa].

Surface interactions[edit | edit source]

Subsystem boundaries have played a key role in the natural history of invention, and in the evolution of correlation-based complexity on earth. Physical surfaces are one important example of such boundaries, and one that we turn our attention to here.

Since object surfaces are their connection to the world around, their properties are important even for macroscopic objects. The fact that smaller objects are more surface and less bulk, nonetheless, provides clues to how things change as one shrinks down.

Here we start a table of interesting surface properties. Please improve it as you get the chance.

Phases associated with surface-interaction between bulk materials and air, plus some of their applications.
Bulk solid Surface composition Important properties Surface material applications
Carbon CO, CO2 clear gases at STP solar nebula C>O ⇒ carbide instead of silicate planets, photosynthesis reduces CO2 into carbon-based life, trapping atmospheric heat
Silicon SiO2 glass 2nm thick fairly-hard solid at STP, good electrical insulator, optically clear, chemically stable floating continents, glassware, windows, integrated circuit gate oxides and insulating layers
Aluminum Al2O3 sapphire/corundum very hard solid, good insulator, optically clear, chemically stable polishing compound, jewelry, ceramic insulators
Copper Cuprite (Cu2O) and tenorite (CuO) soft solids, conductive, green electrical circuit wiring and contacts
Gold ?
Iron Hematite (Fe2O3), goethite (FeOOH), magnetite (Fe3O4) conducting magnetic solids, red/yellow/black ochre pigments, navigation, data storage, ferrofluids
Platinum ?
Silver silver nitrate (AgNO3) soft conductive solid tarnish, precursor to alkali halides in film, antibacterial
Titanium rutile, anatase and brookite (all TiO2) white high-refractive index solids pigments, photocatalysts
Zinc zincite (ZnO) white semi-conducting piezo-electric solids vulcanization catalyst, pigment, food additive, anti-corrosion coating, nanosensors and power devices

Tales of exploration[edit | edit source]

News and notes[edit | edit source]

  • Note in Technology Review on unzipping nanotubes.
  • Water splitting with synthetic photosynthesis[4][5].
  • Neutralizing smoke with aerosol catalysts.
  • Lotus effect and other self-cleaning surfaces.
  • Nanoelectronics in hand and in the works.
  • Energy-producing clothes to keep your batteries charged.
  • Invisibility cloaks and robotic insects.
  • Catalysts that reduce manufacturing costs bigtime.
  • Non-invasive aneurism and cancer treatment kits.
  • Automobiles that clean the air as they run.
  • The story of nanosilver and happy socks?
  • Hydrogen fuel storage in a solid matrix.
  • The milky-way nannite challenge.
  • What else?

Lab/Web sites[edit | edit source]

Size/mobility range blindspots.

Cross-disciplinary texts[edit | edit source]

Books with a non-technical flavor include

  • Bainbridge[6],
  • Di Ventra, Evoy & Heflin[7]
  • and what else?

Books with more technical flavor include

  • Wolf[8]
  • and what else?

Fiction[edit | edit source]

Television/Print series[edit | edit source]

  • Sherlock Holmes by Sir Arthur Conan Doyle, 1859-1930 (cf. "Doyle" search here)
  • Quincy (reruns on A+E Cable TV)
  • Crime Scene Investigation (CBS, Fall 2000, Fri 9pm ET)

Movies and videos[edit | edit source]

  • The Incredible Shrinking Man, 1957 (Amazon)
  • Fantastic Voyage, 1966 (Amazon)
  • Willie Wonka and the Chocolate Factory, 1971
  • The Incredible Shrinking Woman, 1982 (Amazon)
  • Inner Space, 1987
  • Honey - I Shrunk the Kids, 1989 (Amazon)
  • Honey - I Blew Up the Kid, 1992
  • Honey - We Shrunk Ourselves, 1997 (Amazon)
  • A Bug's Life, 1998 (Amazon)
  • The inner life of a cell video.

Theatre/Dance/Music[edit | edit source]

  • The Nutcracker Ballet, 1891 by Hoffman/Petipa/Tchaikovsky/Kirov

Views from asmall[edit | edit source]

Sufficiently small cameras might see things on many size scales at once!
Index Column 1 Column 2
Row 1
Platinum atoms on graphite in the Saint Louis morning sun.
File:Dmpitlo5.jpg
Etched trail of a 238U or 232Th atom recoiling from α-decay
Row 2
File:Practice3.png
Pt/ssDNA/SWNT/holey carbon
Atom clusters with blood cell & Andromeda galaxy in background.

What other settings come to mind for use of "small cameras" to provide insight into processes that take place on multiple size scales?

Examples include:

  • video games whose character can change size over many orders of magnitude.
  • what else?

Tools for exploration[edit | edit source]

Electron microscope specimen: Microworld-3 scale.

Sites[edit | edit source]

Suppliers[edit | edit source]

  • The Intel-Mattel QX3 (now QX5) Microscope and Notes
  • Digital Instruments SPM Shop
  • PASCO and other educational nanoworld tools

Training for exploration[edit | edit source]

Simulators[edit | edit source]

Class activities[edit | edit source]

Assessing course knowledge beyond the model itself[edit | edit source]

How might we broaden our student assessment even in theory courses to credit for any given problem:

  • insight concerning the model's choice, suitability, origin & implementation options,
  • estimates of the size of prediction errors in this particular problem,
  • power in the solution's narrative able to broaden the understanding of others,

as well as the student's facility with...

  • relationships suggested by the model (this may be some equations if the models are mathematical), and
  • the consequence of these relationships for the specific question (e.g. to solve the equations for the variable of interest)?

Instructional Goals[edit | edit source]

1) Offer empirical observation challenges patterned after real nano-world adventures.

For example, begin with applet-based "virtual-microscope" models that provide geometric information on size scales ranging from macroscopic to atomic, and access to...
(a) visceral experience with objects ranging in size from millimeters to atoms
(b) real-world characterization problems open to a wide range of problem-solving styles
(c) tasks start with description/estimation of distances, areas, volumes, and shapes...
(d) ...but can extend to molecule recognition, crystal defect analysis, even nano-assembly.
In some cases through telepresence, web-mediated access to real live structures on the micron and atomic scale will become possible in the years ahead.

2) Offer access to diverse and robust forms of data to work with...

...including a wide diversity of viewpoints, magnifications, data output formats (e.g. prints, digital images, machine estimates) and calculation tools (e.g. 2D Fourier analysis). In the long run, ability to examine a large number of different: regions (presently limited mainly by memory sizes), signals (e.g. diffraction patterns, x-ray and electron energy spectra, force and I-V curves, secondary and backscattered electron images, etc.) and contrast processes (electron phase contrast, diffraction contrast, darkfield and weak-beam contrast, z-contrast, etc.) will be offered as well.

3) Work with models that are in practice unknown, and accessible only through a window which involves some experimental uncertainty so that a "literature of discovery" on individual specimens might in fact be developed over time.

In other words, there is no one right answer or correct way, but only style and resourcefulness and credibility in putting quantitative constraints on what is present in the specimen. As with real world specimens, a literature of discovery (including responsibility for citing previous results) might develop on some of the virtual specimens.

4) Four use-formats considered:

(a) lab notebooks ⇒ scientific report ⇒ peer review (home-project format)
(b) group discovery, model development, and white boarding (modeling-workshop format)
(c) individual estimation ⇒ group estimation ⇒ class discussion (peer-instruction format)
(d) timed empirical-observation challenges for the individual explorer (exam format)

5) All of the tools (so far at least) can be made available free to web-accessible classrooms

One objective here is to let energetic teachers drive content modernization as well as pedagogy, giving book publishers an option to do something they are much better at than modernization, namely following the market.

Overview[edit | edit source]

Individual teachers, equipped with materials they and their students can access via the web, are a developing force in the modernization of both pedagogy and content. Although inquiry-based learning is oft considered a method for helping students master facts and algorithms, the perspective from the modern workplace is that empirical discovery and reporting skills in the subject matter of a course deserve to be a goal in themselves. We show here how the nano-frontier provides a robust setting for challenges that put the student in the shoes of real nano-world detectives, and how diverse challenges can be made available on the web by a single "virtual unknown" for students at home, in lecture settings, and even on timed tests.

Our group has provided industry and university researchers across the state with access to new methods, and atom-resolution microscopy capability using both electrons and scanning probes, for over a decade. In addition, we’ve also had opportunities to further regional contributions in both materials astronomy (the laboratory study of small but previously stand-alone astrophysical objects) and gigascale integrated circuit silicon manufacturing. These experiences, and our contacts as part of a robust and growing regional nano-characterization alliance, give us insight into characterization tools, methods, applications, and most importantly a large and growing list of past and future challenges.

In this context, the proposed project activities will:

  • (i) expand the list of web-accessible nano-worlds that we presently make available,
  • (ii) develop and deploy storylines suitable for a variety of introductory undergraduate science courses based on real (past, present, or future) characterization challenges along with evaluation rubrics in the form of nano-world WebQuests, and
  • (iii) implement/evaluate the effect of these exercises during two years of introductory classes at UM-StL involving a total of about one thousand students.

The goals with respect to participating students are to:

  • (a) increase understanding and ability to gather data, discern patterns, and solve problems posed by real nanoworld studies involving the subject matter of each course;
  • (b) understand and successfully participate in a peer-review of their, and another student’s, report about nano-world observations specific to course subject matter; and
  • (c) enhance awareness of the nano-world, and challenges posed by characterization of matter down to the atomic scale, as it may be encountered in later course work and careers.

Broader Impacts[edit | edit source]

  • 1) Observation and reporting challenges for courses elsewhere: The materials being developed will be deployed on the web concurrently with their use in our courses, and hence immediately available to web connected classes everywhere. To get the word out, we are talking with regional organizations already (e.g. Saint Louis Area Physics Teachers, American Chemical Society, American Association of Physics Teachers, Central States Microscopy and Microanalysis Society). This project will convert teaching assistants into active meeting participants. It further allows us to follow through on undergraduate education committee interest in teacher workshops at national AAPT meetings, and request by an Am. J. Phys. co-editor for a paper on the strategy. A paper for J. Chem. Ed. may be prepared as well.
  • 2) Web-based content-modernization generally: It is difficult for text publishers to lead content-modernization, particularly if the courses don’t directly address specific career needs of the students taking them. This project generates material for augmenting existing (and two emergent content) classes, and makes it available for use by web-connected teachers worldwide. Given the need for inquiry-based content tied to real-world challenges, it could offer a significant contribution by making figures "come to life" in a variety of intro-science classes.

Fleas on Fleas Lab[edit | edit source]

  • Apparatus
  • Pre-lab discussion
  • Lab performance notes
cf. these rubrics for scientific interaction.
  • Post-lab discussion

Powers of Ten Lab[edit | edit source]

  • Pre-lab discussion
  • Lab performance notes
  • Post-lab discussion

See Also[edit | edit source]

Here on wikibooks[edit | edit source]

Related mediawiki sites[edit | edit source]

Web pages[edit | edit source]

Footnotes[edit | edit source]

  1. ↑ P. Fraundorf and Jingyue Liu (2008) "Widening the impact: Informal, introductory and industry nanochallenges", Chapter 10 of Nanoscale Science and Engineering Education (ed. Aldrin E. Sweeney and Sudipta Seal, Amer. Sci. Publ.) (link).
  2. ↑ a b The quartz fishpole balance method developed by Oliver Lowry at the Washington University School of Medicine for weighing individual cells in the early 1940's relied on the reliability of touch exchanges for manipulating picogram sized objects in the presence of ionized air to minimize electrostatic effects. For more on this cf. Janet V. Passonneau, Oliver H. Lowry (1993) Enzymatic analysis: A practical guide (Springer, NY) preview. Invalid <ref> tag; name "fishpolebalance" defined multiple times with different content
  3. ↑ Giovambattista, N., H.E. Stanley, and F. Sciortino (2003) "Potential-energy landscape study of the amorphous-amorphous transformation in H2O" Physical Review Letters 91 (Sept. 12):115504. abstract.
  4. ↑ Richard Eisenberg (2009) "Rethinking water splitting", Science 324, 44-45 html.
  5. ↑ Stephan W. Kohl, Lev Weiner, Leonid Schwartsburd, Leonid Konstantinovski, Linda J. W. Shimon, Yehoshoa Ben-David, Mark A. Iron, David Milstein (2009) "Consecutive Thermal H2 and Light-Induced O2 Evolution from Water Promoted by a Metal Complex", Science 324, 74-77 abstract.
  6. ↑ William Sims Bainbridge (2007) Nanoconvergence: The unity of nanoscience, biotechnology, information technology and cognitive science (Prentice-Hall, Upper Saddle River NJ).
  7. ↑ Massimiliano Di Ventra, Stephane Evoy, James R. Heflin, (2004) Introduction to Nanoscale Science and Technology (Springer 2004) 632 pp. ISBN: 978-1-4020-7720-3 preview
  8. ↑ Edward J. Wolf (2006) Nanophysics and nanotechnology: An introduction to modern concepts in nanoscience (Wiley-VCH, Weinheim FRG).
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