| ▲ | neepi 2 days ago |
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| ▲ | fouronnes3 2 days ago | parent | next [-] |
| However you must concede that the perspective of an outsider can be refreshingly eye opening sometimes, even to experts. Especially when it reveals the arcane practices that make a field difficult to learn - for example here the point about the base being too implicit is very valid. The article is perhaps ignorant of a few things, but its criticism shouldn't be dismissed outright IMO. Accepting constructive criticism from someone less experienced at something is a good exercise in humility, and can often help you improve. It's far from a "curse in any field". |
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| ▲ | neepi 2 days ago | parent [-] | | That would assume that the entire world hasn't already tried this a thousand times over. Measurements are standardised communication tools. If you start changing the definitions, things fall out of the sky and on your head. | | |
| ▲ | yxhuvud 2 days ago | parent | next [-] | | No, changing definitions was exactly how we ended up with SI units. That was a very good (and necessary) thing and definitely not the sky falling down. | |
| ▲ | baxuz 2 days ago | parent | prev | next [-] | | This mindset is why the US is still using barley seeds as a standardized unit of measure. | |
| ▲ | 2 days ago | parent | prev | next [-] | | [deleted] | |
| ▲ | viraptor 2 days ago | parent | prev [-] | | Glad we never changed them and still drink in hogshead, use the original foot reference, and never resolved what base is a megabyte. ;) |
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| ▲ | dns_snek 2 days ago | parent | prev | next [-] |
| You haven't addressed any points the author has made, we don't need to have "experience" in a field to know that ambiguous units are ridiculous and bad. When I'm buying a piece of string for my garden, I don't need to find an agricultural textbook to know whether "10 meters" in agriculture is the same as "10 meters" in engineering, and whether the definition of "meters" depends on whether the string is made out of cotton or polyester. The same is not true for "decibels". People seem to assume that we're too stupid to understand logarithms, we're not. |
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| ▲ | Ekaros 2 days ago | parent [-] | | Well 10 millimetres of rain is different that 10 millimetres thickness for say branch... | | |
| ▲ | kqr 2 days ago | parent | next [-] | | At first I was going to contradict you but then I realised 10 mm of rain is actually a measure of volume or mass, corresponding to 10 kg, right? And of course, people use it mainly as a rate, i.e. 10 kg per hour, or per four hours, or six hours, or 24 hours. And it gets worse when we start talking about snow, the density of which can vary a lot! | | |
| ▲ | Ekaros 2 days ago | parent [-] | | Well depending on area you are counting it on. So yes per square meter it would be 10 kg. Your rain gauge might for example not have 10mm spaced markings... |
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| ▲ | margalabargala 2 days ago | parent | prev [-] | | Could you elaborate on this? If 10mm rain falls, and you have an open collection container, then the depth of the water in that container would be more, less, or the same as the thickness of the branch? | | |
| ▲ | camtarn 2 days ago | parent [-] | | ...as long as the container has straight sides. The area of the opening needs to be the same as the area of the container all the way down, otherwise the two areas don't cancel out. | | |
| ▲ | margalabargala 2 days ago | parent [-] | | Sure you can do that, and now you're measuring something different. The volume of an exotic container is measured in different units than the depth of rain falling from the sky evenly. | | |
| ▲ | camtarn 2 days ago | parent [-] | | I have no idea what you mean here. Exotic containers? I'm talking about something like a measuring cylinder or a straight-sided glass or mug. This StackOverflow answer probably does the subject more justice than I can:
https://earthscience.stackexchange.com/questions/14587/what-... but I'll try and explain it succinctly: What you're measuring is the volume of rain falling per unit area in a given time (usually 24 hours). If you're collecting rain in a vessel, you divide the volume collected by the area of the vessel's mouth to get the volume collected per unit area. And in order to measure the volume in the container, you measure the height of the water and multiply by the area of the vessel's bottom. If the bottom and mouth have the same area, those cancel out and you can just specify the rain height regardless of the size of the container. That is, if you have 1ml of rain falling per square mm over 24 hours, it will produce the same height of water if you set out a big container or a small container, as long as the containers have straight walls. If they don't have the same area, then you can't use the handy mm unit. | | |
| ▲ | margalabargala 2 days ago | parent [-] | | I couldn't have explained it better myself. Glad you understand! Aside from the last bit. The rainfall per unit area is not relevant to the shape of a particular container. 5mm of rain falls regardless of your container shape. Whether that 5mm of rain falling, also means that the water in your container is 5mm deep, is a function of your container shape. It's not a unit problem. If you're trying to measure rainfall in a conical vessel, you can do that, and the conversion from collected volume to fallen rain will still yield the same 5mm out of the sky. |
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| ▲ | foxglacier 2 days ago | parent | prev [-] |
| It's like telling a chemist that moles are a useless complication. They'll swear up and down how important they but have no reasons except that everyone in the field uses them so they must be important. Sometimes conventions live on past the original need they met and experts are blind to that because they're only experts in using the convention, not evaluating conventions. Moles might have made sense when we didn't even know atoms existed and perhaps dB are similar, though I wouldn't know about that one. |
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| ▲ | tzs 2 days ago | parent [-] | | > Moles might have made sense when we didn't even know atoms existed and perhaps dB are similar, though I wouldn't know about that one. Moles make sense because atoms exist. | | |
| ▲ | foxglacier a day ago | parent [-] | | Moles still work without knowing that atoms exist. The quantity being called "amount of substance" not "number of things" reflects that. However, they are still a redundant over-complicated legacy that doesn't need to exist. | | |
| ▲ | Ekaros a day ago | parent [-] | | Moles are used because they are useful abstraction. When you want to get from reaction equation to actual real word having some fixed weight is useful. It becomes useful to have fixed relatively usable quantity to work with. They are relatively decent size for actually weighing out things. And honestly mapping number of elementary particles directly to grams is not unreasonable. Even if because physics of world are tad weird there is still possibility for some sanity checks. | | |
| ▲ | foxglacier 11 hours ago | parent [-] | | They're not necessary, just a complicated way of doing what SI prefixes already do. Chemists don't notice this because they're intertwined with a whole network of conventions that would all have to be discarded at the same time. That's the legacy effect - it's too hard to untangle all at once. Inches are a relatively decent size for measuring lengths too, but people manage without. |
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