[Home]Orders of magnitude/Talk

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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

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