Talk:Order of magnitude

Suggestion: The individual size pages should probably all have a link back to this overview.
Resolution: Not clear.

Suggestion: A comparison of times would also be nice. --AxelBoldt
Resolution: Done.

Suggestion: [Add] dimensionless numbers, like the number of stars in the Galaxy, the number of cells in the human body, and the largest known prime. --AxelBoldt
Resolution: Not done.

Suggestion: [Add] the population of various countries and cities. --LA2
Resolution: Not done.

Suggestion: Add a column of examples for each order of magnitude.
Resolution: Added, then removed.
Discussion

Suggestion: Add speeds (m/s = mps) of light, sound in various materials, ..., running animals, etc.

Suggestion: Add frequencies (Hz) for light, radio, sound, etc.

Further discussion not organized.

Sorry but this bit of Wiki just doesn't do the business for me. I know that I should put the effort in to sort it but I just don't have the confidence to replace all this stuff. Could we get some more views?

What "bit of Wiki" do you mean exactly? What do you think needs sorting? What do you think needs replacing? You solicit views about what exactly? --AxelBoldt

I generally agree that this page, while already very useful, needs work.

First, why is this list of different units of measurement on a page called "orders of magnitude"? The latter does not mean "units of measurement." Why not put it on a units of measurement (or better, listing of units of measurement) page?

I'm not sure that "listing of units of measurement" would be more appropriate. We already have SI unit and conversion of units, and all units are listed there. "Meter" is a unit of length, but 100m, 1000m, 10000m are not. I believe they are often called "orders of magnitude of length".

What we could do though is to break this list up and put the length part on length, the mass part on mass etc., under a headline of "orders of magnitude of length" or similar. That however would lose the connection between different units, such as the connection between length and time given by the speed of light. Maybe we should do both: put it on length, together with nice examples for every order of magnitude, and keep it here as a general reference table. --AxelBoldt

Second, there are names like 1e-15 m. For someone who wants to know what "1e-15 m" means, in the article, we are told: "To help compare different orders of magnitudes this page lists lengths between 10-15 m and 10-14 m." This isn't very helpful for someone who doesn't know what "1e-15 m" means in the first place. For instance, what does that mean, using decimal places? Yes, any well-educated person knows how to figure it out; but a Wikipedia article about X, remember, is always for the benefit of a (perhaps theoretical) person who doesn't know much at all about X.

Larry, I changed 1e-15 m to be hopefully more informative in this regard. What do you think of that style? Also, these pages are not intended to be linked without an alias to a particular measure like [[1e-15 m|20 millionths of an angstrom]], so I do not think we need worry too much about the page names per se. --Eob

Third, I generally agree with the person who said (somewhere) that the titles of these articles could perhaps be stated in more clearly recognizable words and numbers, without symbols, e.g.: 1,000,000,000 meters (or metres, if you insist). What's wrong with that, at least with the magnitudes close to 1?

Fourth, I think the simplest, single examples should be given for each unit of measurement at each order of magnitude. Again, the whole point here is not to make a pretty table but to make concepts clear to people who do not understand them. If we need several tables, grand, let's make them.

In general, try to bear in mind that our task here is to make concepts as simple as possible--it is not to build a merely pretty-and-clever system of webpages. Prettiness and cleverness are good but must be entirely subsumed under the task of making concepts clear to those who do not have them. --LMS

I disagree with the absolute mish-mash of units being used in this table. I replaced angstroms with nanometres, and gave microns their SI name (micrometres), but it still has four different units being used to measure distances (metres, nanometres, astronomical units and light years). Similarly, for time it has seconds, days, years, etc., for volumes it has cubic metres and litres, for mass grams, kilograms and tonnes, for energy joules and electron volts... the whole idea of "orders of magnitude" would be clearer if a single unit is used throughout. -- SJK

My intent was to use at each scale the units that is used most commonly (by scientists and technologists) at that scale. I think, using units appropriate to the scale gives a better intuitive sense of the orders of magnitude. As regards Angstrom, my understanding is that in the 10^-10m range scientists in a lot of fields use that unit a lot (if not mostly). Similarly, I think "micron" is more familiar than "micrometre". --Eob

I think I might be guilty of the 1e-15 notation, so I'd better give a comment. The reason that I started to name pages like that is because there were pages named 100000000km2 and it was very hard for me to count all those zeros. Yes, introducing commas might have solved the same problem. Furthermore, however, km2 (for square kilometres) might be useful for the sizes of countries, but not for the sizes of paper sheets, so it was clear that a consistent system that spanned the entire range of sizes could not be based on km2. One idea, as has been mentioned here, is to use different units for different parts of the spectrum, but this makes knowing/guessing the page name for a given size even harder than the "e" notation. I think that most Wikipedia contributors restrict their contributions to their own field of speciality (religion, science fiction literature, physics, medieval music, ...) and that those who find joy in arranging these order of magnitude pages will know the "e" notation. Those who merely read these pages, really need not worry about the page names. I think it shows now that the expansion of this system into m3, kg, J, s, and perhaps other units proves that it is useful. However, I'm not stopping anybody from renaming the pages or creating redirect aliases. I have no hard feelings about this. I think this was a funny game, an interesting new invention. It wasn't there until somebody invented it, and nobody told us how to do. I'm a strong believer in the try-watch-learn-redo approach. The current system is a try.--LA2, November 27, 2001.

The use of units such as 'hour', 'day', 'year', is bad, because there are a number of different definitions of each of these units. For example, there are several different astronomically defined years, there is the calendar year (whose length varies from year to year, and depends on the calendar being used), there are fixed length years (e.g. the Julian year of 365.25 days used in astronomy.) Which one is it refferring to? Likewise 'day' can be defined astronomically, or on the basis of the calendar (in which case most days are 86400 s long, but a few are 86401 s long, and in theory they can be 86399 s as well), or conventionally as 86400 s.

Of course one could argue that the differences here are too small to make a difference, but I still think that the use of units with varying definitions and varying magnitudes is ugly. Which is why I'd say, stick to the SI second.

I'd admit some scientists still use microns and angstroms, but these units are ugly because they aren't constructed systematically. They are officially discouraged by BIPM, CGPM, national standards laboratories, ISO, and by many of the international scientific unions. They are the metric equivalent of feet and inches... -- SJK

There seem to be two differing views going on here, concept and preciseness. I'm not convinced that the concept of scale is all that difficult to grasp, except when dealing with very large or very small and even then perhaps we're only providing a list of nice facts (grains of sand in a teaspoon v sahara). Conversely exactly what kind of day and precisely how many seconds it has doesn't matter when dealing with scale because the detail is irrelevant except to a scientist who already understands this stuff anyway?

I revert to my original question of the purpose of this all is, except that it creates a lot of pages? -Rjstott

Moved this from "TalkAboutExampleColumn":

I think the example column should be placed immediately after the column of dimensions that it's an example of. As it is now, it's unclear what dimension things in the example column are an example of; for example, is the Sun an example of something that is 10⁹m in diameter, or is it an example of something with an area of 10¹⁸m²? This gets even more confusing when mass is considered as well. I'll move it over and see if it looks okay.

There, fixed. If everybody hates this, revert it; otherwise I'm going to add empty example columns for the other measurements as well for future expansion. :)

Hmmm, I think having an example for every unit might clutter up the table too much. My intention of lining things up in rows the way I did was to show a general sense of order of magnitude of objects that have "normal" densities (within an order of magnitude of water at 1000 kg/m³). But perhaps this is not appropriate as things like sub-atomic particles and galaxies have densities that are much-much bigger or smaller. So perhaps on reconsideration we should try to keep the table clean and not put examples columns, but just have people link down to the pages to see the examples. --Eob

Hi 129.128.164.xxx, thanks for entering all those examples, but I think that now the table is getting too cluttered up and some of the examples are not in the individual pages. I suggest we do get rid of the examples column and move them to the individual pages. That way they will be more useful in other pages that link to those pages. --Eob

Heh. Sorry, got a bit carried away and wasn't reading Talk updates while I worked. :) I was getting those examples off of http://math.ucr.edu/home/baez/distances.html for the most part, if you want more precice measurements. I think it'd be good to have at least a few examples scattered throughout the range of this table, however; otherwise the measurements are just meaningless numbers. - BD, from a public terminal

Here is my reasons for not including examples in the table:

1. I think the table should be as clean as possible. This will become particularly important if we add columns for time, temperature, pressure, etc.
2. The formatting on this table is tricky because of the use of HTML tables. Many people will have problems editing it if we are going to keep on adding examples. (In fact some of the recent edits had bad HTML which might have caused problems with some browsers.) I think that it should be more like the periodic table which does not get modified very often once it is set up.
3. Having the same info in two places would make it hard to maintain.

The use of the lowercase "e" in these entries is completely wrong. Lowercase "e" is the notation of the natural logarithm -- Capital "E" is the correct shorthand used in scientific notation to denote the × 10^ in n × 10^y. I will move these to the correct capitalization in the next few days unless somebody can convince me that this is not a good idea. --mav

Go for it. I'll put links back to metre from each 1e-11 m-type page -- Tarquin 09:13 Aug 5, 2002 (PDT)

OK, I have fixed all the links and edit links and will be working on that version at Orders of magnitude/Temp. --mav

I've just noticed that --April uses lowercase e on her Simple Science wiki: http://www.renaissoft.com/april/cgi-bin/wiki.pl?Exponential_Notation

Maybe that is where this came from. Anyway capital "E" is far better even if some people do use lowercase "e" for this; otherwise there is confusion as to whether e is a shorthand for × 10ⁿ or if the e stands for e which is the base to the natural logarithm. In either case, the lack of spaces between the characters is just plain wrong no matter what and m3 is not nearly as clear as m³. --mav

Aha, I've found your evil hidden plot, Mav! Ahem. I was under the impression that including spaces was incorrect. Certainly it looks very very wrong to my eyes. --Brion

Looks fine to me -- is there a ref. for how this is supposed to be done? I've just been expanding on the example Axel placed in scientific notation (which conforms to the way I've always seen the shorthand notation). --mav

I've never seen em with spaces. My experience of E-notation is overwhelmingly no spaces, and usually with an explicit + sign for positive numbers. I've been looking for some kind of official standard either way, all I can find is notes about number formatting functions in computer languages and spreadsseets (invariably without spaces), or notes for people taking standardized tests that they should not use spaces in their scientific notation. Proper scientific notation, of course, would use superscripts, but we can't put those in titles. --Brion

Hm. Knowing that others do not use spaces would have been useful info back when I started this process. However its a bit late now. Besides, not having the spaces doesn't work at all for me for negative exponents; 1E-10 m looks way too crowded; gives the impression that "E" is a variable and that "-" indicates subtraction. What do you think? --mav

Had I known you were going to blindly rename a gazillion pages on dubious grounds, I would have squealed earlier. ;) 1E-10 m looks fairly normal, though 1e-10 m looks even better. *cough cough* On the other hand, 1 E -10 m looks... bizarre. It looks like there were supposed to be more characters and somebody accidentally deleted them. --Brion

As was stated before the lowerecase e is wrong. Thus the change. Everything else really is more of a matter of personal taste. I will stop moving additional entries for a while and concentrate on improving the content. --mav

[[10E^-10]]? Guess not. It would be interesting to see how that parsed in a browser's location bar.... --KQ

If we could use superscripts, we'd just use [[1×10^-10]]... --Brion

I frequently miss the obvious. --KQ

Me too! We should invite it over more often. --Brion

I just asked Axel to weigh-in on the issue here. If Axel agrees with Brion that the spaces should go then I move the articles myself and fix the links. --mav

Well, so much pressure! I definitely like E better than e, mainly because most calculators use E, and everybody else uses exponential notation anyway. Regarding the space issue I don't have strong opinions and could live with both solutions, but If I were completely free to choose, I'd tend towards writing them without spaces. AxelBoldt

I just found this from Axel's talk page. I use a lowercase letter, no spaces, and no plus sign. (Does that mean that I liked them how they were originally?) I don't see any grounds for calling any convention wrong; they're all just half assed attempts to do without superscripts, and we should have every likely format, with redirects. — Toby 16:03 Aug 21, 2002 (PDT)

Hm. What to do. Over half of the articles and links are in the [1 E n unit] format. It also appears that there are several valid ways to express this notation which includes the now dominant form. Since Axel doesn't think the spaces should be removed (only has a highly qualified preference) I say that I should continue with the format I was working with (this represents far less work). That is unless somebody feels strongly enough about the no space notation to help with the moving. --mav

I don't think it matters so much what the article title is, since I find them all acceptable. My big deal is that redirects should be made for all of the notations that have been tried in the past (and are thus likely to be tried in the future). I'll help with that; let me know what I should do. — Toby 21:02 Aug 22, 2002 (PDT)