Cell Size and Scale

October 28, 2009 6:50 AM

Cool app lets you zoom in from a coffee bean to a carbon atom, so that you can compare sizes. Along the way, you see a grain of sand, a skin cell and many other tiny things. This is the first time I've ever had a sense of these objects' sizes. Cells are actually bigger than I thought they were. I wish the zoomer would keep going. I want to see some sub-atomic particles on the scale.
posted by grumblebee (43 comments total)

Neat.
posted by General Tonic at 6:57 AM on October 28, 2009

Beyond cool. Super-cool. Wish I could give this 10^1 favorites.
posted by Joe Beese at 7:00 AM on October 28, 2009

Coming right up:

http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/
posted by texorama at 7:04 AM on October 28, 2009 [3 favorites]

Nice. If there was ever a use for vector graphics, this is it. It's much more satisfying than the typical site that tries to show scale by snapping from one scale to the next. You can smoothly get a feel for how big some things are compared to other things.

I would like to see it zoom out to show the earth and the solar system, but I wonder if that would require logarithmic scaling, which would not feel as intuitive.
posted by mccarty.tim at 7:07 AM on October 28, 2009 [1 favorite]

While it doesn't sound like much, please understand that I don't say this lightly:

Neat!
posted by rusty at 7:12 AM on October 28, 2009

grumblebee - thanks very much for this. Only missing the ability to scale out to al la XKCD - I know its height though.
posted by dangerousdan at 7:14 AM on October 28, 2009

I think it's already using logarithmic scaling in a sense -- every 'step' that you move the slider increase the scale by a factor of 10.
posted by chrismear at 7:16 AM on October 28, 2009

Am I the only one who is disappointed these aren't real microscopied images?
posted by tybeet at 7:28 AM on October 28, 2009

Love the link! (please don't call it an app, though. that word is really starting to get to me)
posted by localhuman at 7:28 AM on October 28, 2009 [3 favorites]

Neat. Reminds me a bit of ye olde video Powers of Ten, which we viewed in middle-school science class.
posted by Maximian at 7:33 AM on October 28, 2009 [1 favorite]

Very cool - but could someone explain why it looks like the sperm could only hold one chromosome? They seem almost the same size (minus the tail.)
posted by Rinku at 7:35 AM on October 28, 2009

Yeah that X chromosome seems all kinds of too big.
posted by shakespeherian at 7:46 AM on October 28, 2009

I was also surprised at the size of the larger cells. I had to go open a salt packet and take a look at a few grains of actual salt to get my mind around it. Are some large amoebas really around the same scale as a grain of salt, and some paramecium not too much smaller than that? I mean, I can see individual grains of salt with my naked eye, could I see amoebas and paramecium with a magnifying glass? I always thought this was at-least-decent microscope territory.

(goddamnit, why don't I have a magnifying glass?)
posted by Reverend John at 7:59 AM on October 28, 2009 [1 favorite]

Whoa, I kinda got a little vertigo zooming out from the carbon atom.
posted by Reverend John at 8:03 AM on October 28, 2009

Something is odd with the proportions. For example, the skin cell says 30μm, and the significantly smaller sperm says 60x5μm, which is the same 30μm. Strange. It could be measuring the largest dimension against the largest dimension--and with the sperm cell's tail, that might be correct--but the labeling is very weird. Also, the bakers yeast is oddly described as 3x4μm.
posted by milestogo at 8:09 AM on October 28, 2009

could someone explain why it looks like the sperm could only hold one chromosome

Sperm use special packing proteins called protamines to squish up the DNA more compactly than the histone proteins used in the nuclei of normal cells.
posted by kersplunk at 8:12 AM on October 28, 2009 [6 favorites]

My feeling is that the 60 x 5 thing is that it's showing a length x width measurement, not doing any sort of scientific notation.

This is very cool.
posted by cider at 8:15 AM on October 28, 2009

Similar to this.
posted by tighttrousers at 8:20 AM on October 28, 2009 [2 favorites]

Actually, I believe that atoms don't really have a distinct shell, rather they each have electrons in a probability distribution that extends over the entire universe, but which is just clustered in one spot. I'm not sure about that though.
posted by delmoi at 8:26 AM on October 28, 2009

could someone explain why it looks like the sperm could only hold one chromosome

Sperm use special packing proteins called protamines to squish up the DNA more compactly than the histone proteins used in the nuclei of normal cells.

As a result, sperm DNA is sixfold more highly condensed than the DNA in mitotic chromosomes.
For more details: DNA packaging and organization in mammalian spermatozoa: comparison with somatic cells.
posted by Kabanos at 8:26 AM on October 28, 2009 [1 favorite]

Also, I havn't looked at this but aren't chromosomes 'unpacked' when undergoing mitosis, so they are much larger then they are when packed into a nucleus.
posted by delmoi at 8:27 AM on October 28, 2009

but could someone explain why it looks like the sperm could only hold one chromosome?

A couple of reasons, as I understand it. (Caveat: it's been a while since I've had biology.) First, the chromosome you are seeing in the picture is a compacted form present only during cell division, and in that form it's attached to some additional proteins which aren't present most of the time, making it much shorter in length, but larger in volume. (Wikipedia: chromosomes in eukaryotes, esp. Fig. 2; the two rightmost structures in that figure are present only during cell division.) Second, cell division is complete and those extra proteins are gone before the sperm takes on its final, familiar head-and-tail form. (Wikipedia: spermatogenesis.) Third, even some of the proteins normally associated with chromosomes outside of cell division are eliminated and replaced with smaller ones, and the chromatin (DNA+associated proteins) is packed very tightly. (Wikipedia: chromatin, "During spermiogenesis, the spermatid's chromatin is remodelled into a more spaced-packaged, widened, almost crystal-like structure.... The histones are mostly displaced, and replaced by protamines (small, arginine-rich proteins).") Fourth, nearly the entire volume of the sperm's head consists of the nucleus, unlike most cells where the nucleus is a much smaller part of the volume of the entire cell. (Wikipedia: diagram of human spermatozoa.)

But the sizes seem about right to me. The length of the sperm shown, including the tail, is about twice the diameter of the skin cell shown. 7μm seems about right for a human chromosome during metaphase; this paper has some images of mammalian chromosomes with scale bars.
posted by DevilsAdvocate at 8:30 AM on October 28, 2009 [4 favorites]

I want to see some sub-atomic particles on the scale.

Part of the problem is that "size" is not well-defined for subatomic particles. Even for atoms the "size" can vary depending on how one defines size. And as delmoi points out, if you define size as "how far away the atom's electrons could theoretically be," then yes, the size of an atom is the size of the universe itself, and that's not a particularly useful definition, but there are several other possible definitions which are useful for different things, even though the different definitions give different sizes.
posted by DevilsAdvocate at 8:40 AM on October 28, 2009

My feeling is that the 60 x 5 thing is that it's showing a length x width measurement, not doing any sort of scientific notation.

Yeah that's right. I'm wrong. Thanks.
posted by milestogo at 8:52 AM on October 28, 2009

This whole site is cool. Many thanks.
posted by bearwife at 9:19 AM on October 28, 2009

I want to see some sub-atomic particles on the scale.

But then you wouldn't know where you are, and you'd be walking around bumping into things.
posted by StickyCarpet at 9:20 AM on October 28, 2009

The amoeba portrayed is indeed large. It can be probably seen with a magnifying glass.
posted by dov3 at 9:38 AM on October 28, 2009

Hmm, speaking of cells:

The largest biological cell is often cited as the ostrich egg, which is about 15 cm (6 in) long and weigh about 1.4 kg (3 lb). This is a myth. There are at least several biological cells larger than an ostrich egg, despite the fact that even numerous scientists and laypeople believe the ostrich egg is indeed the largest biological cell. The ostrich may actually be the heaviest cell, but this has not yet been tested.
...
Largeness refers to size, not weight, so the ostrich egg is definitely not the largest biological cell. The first type of cell larger than the ostrich egg are nerve cells in especially long animals, such as the Giant Squid and Colossal Squid, which may have nerve cells as long as 12 m (39 ft). This is about 80 times larger than an ostrich egg
...

in humans, the longest nerve cells are about 1.5 m, running from the base of the spine to the toes.

From here, a page that managed to jam an impressive number of ads around not all that much text...
posted by delmoi at 10:31 AM on October 28, 2009

I think it's already using logarithmic scaling in a sense -- every 'step' that you move the slider increase the scale by a factor of 10.

Hm? That little mm scale in the top left corner sure zooms in a linear fashion for me when I drag the slider. How else would you zoom?
posted by rokusan at 10:43 AM on October 28, 2009

Largeness refers to size, not weight

Yes, but on the other hand it's unclear whether "largeness" refers to length between the two most distant points, or volume. If we're talking volume, the ostrich egg is still the largest single cell. (Despite the attempted obfuscation by the linked page, which admits "One might argue that" the ostrich egg is largest by volume, then goes on to irrelevantly cite another cell which is longer, but also smaller in volume, than the ostrich egg.)
posted by DevilsAdvocate at 10:43 AM on October 28, 2009

That little mm scale in the top left corner sure zooms in a linear fashion for me when I drag the slider.

No, it doesn't, unless it's behaving very differently for you than it does for me.

The small square in the scale display is 1mm when the slider is at the far left, and 100pm (or 0.0000001mm) at the far left. If it were scaling linearly, the square would be the average (arithmetic mean, to be precise) of those two, 0.50000005mm, when the slider is at the halfway point. Instead, it's about 1μm, close to the geometric mean of the two.
posted by DevilsAdvocate at 10:50 AM on October 28, 2009 [1 favorite]

this is fantastic! seeing subatomic particles would be really great.
posted by glaucon at 11:11 AM on October 28, 2009

I've just spent a good 30 minutes going up and down this slide. It's tres awesome.
posted by dabitch at 11:58 AM on October 28, 2009

<> I want to see some sub-atomic particles on the scale.
&
<> this is fantastic! seeing subatomic particles would be really great.

This app wouldn't work well for that. You would be scrolling through a few levels of whitespace before you got there. There's no objects with comparable scale on the way down.

Let's put it this way: if the outer orbital of carbon were the diamater of Chartres cathedral, the nucleus would dance on the head of the proverbial pin.

<> I believe that atoms don't really have a distinct shell, rather they each have electrons in a probability distribution that extends over the entire universe,

When you observe them they collapse back to their 'natural' size :)
posted by clarknova at 2:02 PM on October 28, 2009

I half expected to zoom past Tucker Carlson's testicles at some point.
posted by jimmythefish at 3:42 PM on October 28, 2009

I want to see some sub-atomic particles on the scale.

hop on the A train and get off at the museum of natural history...the planetarium has a "powers of 10" walkway around the middle of the great sphere with various objects on display to compare with the sphere. It starts with 'if the sphere is the size of the known universe, then this is a large galactic cluster...' winds through 'if the sphere is the size of the sun, then here are the planets to scale' and heads on into the subatomic realm. the interesting part is all the sizes between 'atom' and 'quark' where "There are no known objects at this scale"
posted by sexyrobot at 7:22 PM on October 28, 2009

While I agree with delmoi's point about the "size" of an electron field being theoretically universal, wouldn't this be easily solved by taking a mole of carbon, and then dividing the size of that by a mole in order to get to a reasonable estimate of the size of a single carbon atom?
posted by Navelgazer at 11:16 PM on October 28, 2009

delmoi is right, but in kind of a silly way. The electron probability distributions you get from the Schroedinger equation have a factor out front like exp(-r/r₀), where r₀ is usually what you call the "radius" of the orbital. This factor is not zero for any electron-nucleus separation r. If you try to locate the electron (I think this is one application of very brief laser pulses), about a third of the electrons will be farther from the nucleus than r₀; only about 5% are farther than 3r₀. If you could interrogate every atom in a mole of carbon, you would find on average one bound electron farther from its nucleus than 55r₀, which (taking the radius from the original link) is two nanometers. Or perhaps you have to square the wavefunction, and so the one-in-a-mole electron separation is 23r₀. Either way, this is a lot smaller than the universe.
posted by fantabulous timewaster at 5:18 AM on October 29, 2009 [1 favorite]

Seems more likely to be a fallacy of confusing the model with the system being modeled. Those always look embarrassing once the underlying system is actually understood.
posted by fleacircus at 10:05 PM on October 31, 2009

I can see individual grains of salt with my naked eye, could I see amoebas and paramecium with a magnifying glass? I always thought this was at-least-decent microscope territory.

Yeah, it's possible. You can make out the larger species at 10x or so. However, the difference between looking at a grain of salt and a living cell is that the cell is likely near to transparent (to say nothing of the fact that it's probably also floating or swimming around). One of the big benefits of using a microscope is controlling the light so that you can actually see cells by refraction.
posted by zennie at 10:07 PM on October 31, 2009 [1 favorite]

Am I the only one who is disappointed these aren't real microscopied images?

The images wouldn't be as clear or as easy to compare as you might think. Drawing is better for something like this.
posted by recurve at 1:27 AM on November 1, 2009

nikon universcale has been mentioned previously and does make a good job of going from the very big to the very small.
posted by fay at 6:47 AM on November 1, 2009

I'm shocked by the relative size of the X chromosome compared to everything else around it...
posted by RockCorpse at 4:08 PM on November 1, 2009