It turns out people can be confused about things and not tell you. Also, I suspect that you have met some people without having a conversation that required them to figure out that there are 100,000cm in a km or 1,000,000mL in a cubic meter or whatever.idobox wrote:But people who don't know the micro-milli-kilo-mega? I've lived most of my life in France, and I have yet to met somebody who gets confused by it. I've even used k€ and M€ at my work.gmalivuk wrote:What you are claiming is patently false, idobox. I have definitely talked to people who don't remember all the metric prefixes or how to convert between them. Not everyone pays for their own water, so many likely don't know that there are 1000L in a m^3. And as I said, they have no excuse but stupidity. Americans can at least excuse their ignorance by not being able to quickly multiply things by the 231 cubic inches in a gallon, for example.

Also, there are 35840 ounces in an imperial ton, and 63,360,000 mils in a mile. The first one required some mental math, and the second one I already knew. I'm probably not the right person to challenge with odd USCS units when you're trying to make a point about its confusingness.

For one thing, it helps when idiots such as yourself toss out a "challenge" question to try to "prove" how inferior the USCS is.And you seriously memorize numbers like 63,360 ? why?

Do you remember any old phone numbers or addresses or friends' old phone numbers or addresses or the price of your regular lunch at your regular lunch cafe or whatever? I don't need to "memorize" a five-digit number in order to remember it. Do you remember how to get places in your town? Even places you don't go often? That requires a lot more "memorization" than 5 digits and yet you do it automatically, even though you could just check Google every time you need to go there.

Knowing there are 1609.344 meters in a mile required a few seconds of conscious effort to memorize, as did 43,560 square feet in an acre, but I really don't think 63,360 inches in a mile did.

But in any case, do you really mean to tell me you've never memorized more than two or three digits of a number like pi or e or sqrt(2) or the golden ratio, even though you'd never do math that needed more precision than that without also being able to just tell a computer or calculator to spit out the extra digits?

Calories aren't an SI unit, either. Nor are minutes, hours, days, months, or years. Nor are light years or parsecs or kilowatt-hours or atmospheres or degrees Celsius. And yet, I'm pretty sure you've used most or all of those at one time or another in a scientific setting, without ever worrying about the non-SI nature of your units. (Incidentally, liters *are* metric units, as are hectares. Metric is not the same as SI, and I'm tempted to conclude that the confusion between the two is just another example of the lazy, fuzzy-headed reasoning people start to slip into when the only math they ever have to do is slide a decimal point one way or the other.)That's what I was taught in primary school. Liters are not a scientific unit, and should be used only for quantities of fluids.

I thought you said people weren't confused by unit conversions with the metric system?You can still use cc to measure fluids, but people tend to be confused by the cube law and think there are 10 cc in a cubic decimeter