Sliding down to the carbon atom

By Phil Plait | November 12, 2009 11:00 am

The folks at the Genetic Science Learning Center at the University of Utah have a nifty little interactive gizmo on their web page which shows the relative sizes of small objects from a coffee bean down to a carbon atom. A slider along the bottom (or just running your mouse left/right on the graphic itself) changes the scale, so zoom in and out on the objects. You fly past a mitochondrion, E. coli, all the way down to a carbon atom. The sizes are given too.

carbonslider

This is pretty slick, and helpful; people (me included) tend to have a miserable sense of scale. If I had two wishes for this, it would be that they included a human hair, since that’s something of a standard for comparison to small things (a hair is 50 – 100 microns in diameter), and that they make the opposite one to zoom out from a coffee bean to the observable Universe. That would be pretty cool!

Note: Yes, of course I’ve seen "Powers of Ten". I remember the original, with Philip Morrison narrating. I used to sit in the Smithsonian on field trips when I was a kid and watch it over and over. I was always doomed to dorkhood.

CATEGORIZED UNDER: Cool stuff, Science
MORE ABOUT: Powers of Ten

Comments (48)

  1. Very cool, Dr. Plait.

  2. Brian Schlosser

    “Powers of 10″ is great! Skip the prequel, though. “Powers of 1″ is not nearly as interesting.

  3. Brian Schlosser

    For serious, though, thats really amazing. I knew that some amoebas were visible to the naked eye, but I never knew that a human egg or a paramecium could be visible as well… truly astounding!

  4. “…they make the opposite one to zoom out from a coffee bean to the observable Universe.”

    Isn’t that *your* job?

    (j/k, though it’s obviously not the job of Genetic Science Learning Center at the University of Utah)

  5. Jeremy

    @2 Brian

    Well don’t forget about “Powers of zero”! Though it didn’t really go anywhere

  6. Jakub

    XKCD rulez :) “Powers of 1″ maybe not as interesting, but waaay more funny :)

  7. Phil, in regards to something that lets you zoom out to the known universe, have you seen this?

    http://www.nikon.com/about/feelnikon/universcale/index_f.htm

  8. I too like demonstrations of scale. I especially like ones that resize an object to something more commonly experienced, like say if an atomic nucleus was the size of a corn kernel, the first electron would be 300 feet away (or some such easily understood distance).

  9. Tom

    … and it gives scales in standard form! Might well bookmark this, and use it in my classroom… Thanks!

  10. Yes. I saw it in the Uncommon Descent blog.

  11. dcsohl

    Actually, PsyberDave@7, if you blew up a hydrogen atom so the nucleus was the size of a corn kernal (about 0.25 inches), the ground state of the electron would have it orbiting 3000 feet away.

    Well, you were only off by 1 power of 10, at least.

  12. John Swindle

    Some things that were too small to be depicted:
    A teabagger’s brain
    A politician’s spine
    Donald Trump’s heart
    Insurance executive’s conscience

  13. Brian Schlosser

    @6 Dangit! I was not consciously quoting XKCD… I thought I came up with that quip on my own. Up reflection though, I do remember that specific cartoon. I should have known that anything clever I came up with, Randal Munroe came up with first…

  14. !astralProjectile

    Of course if you zoom in a lot farther you will end up at 742 Evergreen Terrace.

  15. PG

    @Brian, Actually Kirk come up with it in “Let That Be Your Last Battlefield” when he asked that the volume be increased “by a factor of 1.”

  16. Outsider

    Cool! But how can 23 of those chromosomes fit inside that tiny sperm??

  17. Robert

    Wait… an X chromosome is bigger than a sperm cell or a red blood cell?

  18. 10. Brian Schlosser Says: I should have known that anything clever I came up with, Randal Munroe came up with first…

    Or Steve Allen (ref: MST3K)

    J/P=?

  19. AndreasB

    Robert: It’s explained in the notes.

  20. Nick

    Phil, there is one showing everything from the whole Universe down to a proton:
    http://www.nikon.com/about/feelnikon/universcale/index.htm

  21. Mike

    Maybe I’m just old, but I really liked the pre-Phillip Morrison version of Powers of Ten. That was the one with the dispassionate female narrator, and the clocks on the side, trying to illustrate the relativistic time scaling that came with moving backward so fast. I was kind of disappointed when the Air and Space Museum replaced it with the second version.

  22. Wayne Robinson

    A water molecule (275pm) is smaller than a carbon atom (340pm)?

  23. tiggerbone

    Ginchy! That reminds me, you once put up a video which showed scale on an entirely different level. It involved several of the planets in our solar system, followed by various stars. Do you happen to remember what I am talking about? I would like to send links of both that and the above slider to some friends of mine. They could use the perspective.

    And yes, Powers of Ten was amazing. :)

  24. Nigel Depledge

    Robert (19) said:

    Wait… an X chromosome is bigger than a sperm cell or a red blood cell?

    The highly condensed form of DNA in the sperm is explained in the notes, as has been pointed out by another commenter.

    However, the red blood cell (erythrocyte) isn’t. Most genetics students are expected to know (and there is no reason why most members of the general public would) that erythrocytes contain no DNA. They are essentially just little biconcave discs stuffed full of haemoglobin.

  25. Nigel Depledge

    Wayne Robinson (25) said:

    A water molecule (275pm) is smaller than a carbon atom (340pm)?

    This is a very interesting question.

    The short answer is “yes”, but that’s not very fulfilling.

    There are actually two aspects to the answer.

    The first is: how do you define the “edge” of an atom or molecule? After all, the electrons orbiting the nuclei are not clearly-delimited balls, there are smears of probability. The convention is to define a surface that bounds 99% of the electron density (i.e. the surface within which the electron is 99% likely to be found). Now, it is possible (but, I feel, unlikely), that different conventions have been applied.

    But the answer is, I think, more likely to be tied to the second aspect, which is this: All nuclei have positively-charged protons and all except 1H also have neutrons. The positive charge of the nucleus electrostatically attracts the orbiting electrons. However, the strength with which it does this differs from one element to another. This variable affinity for electrons is a measurable property of an atom and is called electronegativity. Out of all the elements known, Oxygen has the second-most electronegative nucleus (the most electronegative being Fluorine). This means that its electron cloud is more tightly bound around the nucleus than is the case for, say, carbon. The lower electronegativity of the carbon nucleus allows its electron cloud to be more diffuse, and hence of a larger extent. The hydrogen atoms in the water really don’t add much bulk at all, because they are so much smaller than either oxygen or carbon.

    I will admit, it was a surprise to see how big an effect this has.

  26. Nemo

    The notes explain the X chromosome vs. the sperm cell. As for red blood cells, they don’t carry genetic material. But the pictured X chromosome also seems too big even for the pictured skin cell (given that it has to fit with all the other chromosomes within the nucleus). So it is puzzling.

    Edit: Ah, Nigel beat me to the red cells.

  27. Nigel Depledge

    Adding to my comment above, a third aspect has just occurred to me, and that is the layering of electron shells about the nucleus. However, since both oxygen and carbon use only the 1s, 2s and 2p orbitals, this does not make a difference in this case.

    (Carbon is 1s2 2s2 2p2 and oxygen is 1s2 2s2 2p4 .)

  28. Nigel Depledge

    @ Nemo (29) -

    I think the key point is that the X-chromosome is a diploid mitotic chromosome, depicted as chromosomes are usually seen when viewed with a light microscope. It has very little thickness.

    The skin cell, OTOH, is probably a squamous epithelium cell, which has (very roughly) the same thickness as length and width.

  29. Nigel Depledge

    I cannot help but wonder why they stopped at the scale of the atom.

    Maybe they could not think up a sensible way to depict electrons, neutrons, protons and quarks.

  30. “I cannot help but wonder why they stopped at the scale of the atom.”

    I think you answered your own question a couple of comments earlier. Below the atomic level ‘size’ starts to lose it’s meaning.

  31. Gus Snarp

    I too think it would be nice if this went out as well as in. At least to the scale of say, VY Canis Majoris, or the Milky Way, maybe the Universe. I find this one cleaner and easier to use than the Nikon one. I would also love to see one for time, since understanding the vast amount of time between the origin of the earth and the advent of the modern human is so important to grasping the concept of evolution.

  32. Sean McCorkle

    Mike @24

    Maybe I’m just old, but I really liked the pre-Phillip Morrison version of Powers of Ten. That was the one with the dispassionate female narrator,…

    … with the british accent!

    I’m with you on that! So were many of my friends in college! We were somewhat disappointed with
    the “real” version when it came out because they didn’t use the same great narrator from
    Powers of Ten – A Rough Sketch.
    (No disrespect to Morrison, though)

  33. This site compares dimensions of various fictional characters and space structures alongside human-made structures and natural objects.

    Starship Dimensions

    Or

    http://www.merzo.net/index.html

    Have fun searching for your favorite characters and ships! It even points you to resources in case you feel like designing your own ship.

  34. !astralProjectile

    Mike and Sean:

    Agreeing, although as I recall she was proposing some Hoyle-isitc steady-state philosophy.

    Also emphasizing Nigel’s comment about the shells. For example helium is smaller than hydrogen because the 1s shell gets pulled inwards.

  35. Torbjörn Larsson, OM

    Scale comparisons owns, there is always something that astounds.

    Most genetics students are expected to know (and there is no reason why most members of the general public would) that erythrocytes contain no DNA.

    I know you know this, but this depends on species. I vaguely remember a graphic showing the awesome span of red blood cell size. Species that have a huge metabolism would benefit from small, high surface-to-volume ratio, cells without nucleus for efficient oxygen and carbon dioxide surface exchange. IIRC some birds, that have so many other functions geared towards this, have small but not human-like unnucleated cells.

    Such images may be a reason why the general public would know of how species like humans ‘cheat’ on the viscous and small scale properties of blood and blood vessels. Another set of images on scale that should be more spread IMHO.

  36. WetChet

    My brain hurts after watching the Nikon version. Feels like a visit to the Total Perspective Vortex.

  37. Torbjörn Larsson, OM

    Out of all the elements known, Oxygen has the second-most electronegative nucleus (the most electronegative being Fluorine). This means that its electron cloud is more tightly bound around the nucleus than is the case for, say, carbon.

    A fourth, and I suspect the strongest effect, is on the expectation time of the electrons in water molecules due to oxygen. IIRC the valence electrons are so strongly kept by the oxygen atom that they very rarely visit the hydrogens.

    That means that you effectively see an oxygen with two protons stuck to it, or in an electron density cloud picture you would not see much of anything except the oxygen. As you say, the hydrogens don’t add bulk – rarely any at all, AFAIU!

  38. Nigel Depledge

    Torbjörn Larsson OM (40) said:

    A fourth, and I suspect the strongest effect, is on the expectation time of the electrons in water molecules due to oxygen. IIRC the valence electrons are so strongly kept by the oxygen atom that they very rarely visit the hydrogens.

    That means that you effectively see an oxygen with two protons stuck to it, or in an electron density cloud picture you would not see much of anything except the oxygen. As you say, the hydrogens don’t add bulk – rarely any at all, AFAIU!

    While this is true, I don’t think it explains why the oxygen atom (which typically has 8 protons, 8 neutrons and 8 electrons) should be smaller than the carbon atom (which has typically 6 protons, 6 neutrons and 6 electrons). My feeling is that the electronegativity of the oxygen (which, of course, causes the disproportionate expectation times in water) is the main culprit.

  39. Nigel Depledge

    Torbjörn Larsson OM (38) said:

    I know you know this, but this depends on species. I vaguely remember a graphic showing the awesome span of red blood cell size. Species that have a huge metabolism would benefit from small, high surface-to-volume ratio, cells without nucleus for efficient oxygen and carbon dioxide surface exchange. IIRC some birds, that have so many other functions geared towards this, have small but not human-like unnucleated cells.

    As you guessed, I was referring only to human erythrocytes. I should have made that clear.

  40. Nigel Depledge

    No Astronomer (33) said:

    I think you answered your own question a couple of comments earlier. Below the atomic level ’size’ starts to lose it’s meaning.

    Well, you may be right there, but that did not stop them from representing the carbon atom in a wholly unrealistic, diagrammatic way.

  41. DennyMo

    I’m surprised that XKCD has been mentioned, but not this one:
    http://xkcd.com/485/

    or this one:
    http://xkcd.com/482/

  42. Sgt Skepper

    Just wanted to thank Nigel for the explanation of why the water molecule is smaller than the carbon atom. Ta!

  43. Nigel Depledge

    @ Sgt Skepper – you’re welcome.

    I just remembered that I had intended (but forgot) to go on to say that the vast majority of chemistry arises through differences in electronegativity and numbers of electrons from one element to another, so electronegativity is a fundamental property (as far as chemistry is concerned).

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