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Comment by meaty | Hacker News Reader

Why does everyone still have to use imperial/US measurements. Metric please or I have to break out the calculator.

The real pain starts when you use derived units. How many pascals are there in a pound per square inch? And what is the ratio between DPI and pixel per mm^2

People from the US use US measurements, surprisingly.

Yes and look where that got you:

http://en.wikipedia.org/wiki/Mars_Climate_Orbiter

Yes and also 4 rovers on Mars, and 12 astronauts on the Moon.

The problem with the MCO disaster wasn't mixing up units, it was a sub-contractor failing to follow a specification properly, which can happen for any number of reasons. Also, it's not the only way that such missions can fail. Let us remember that since the mid-90s there have been 2 failed US Mars missions as well as a failed European mission (the Beagle 2 lander), a failed Japanese mission, and 2 failed Russian missions. As well as one and only one successful European mission and 8 successful US missions.

I agree it's not the only failure mode, but it certainly is the lamest so far.

Any success the US had has nothing to do with using the obsolete Imperial system. Glad you were given the opportunity to do a little bit of "USA, USA, USA" fist pumping though.

Atwood's an American. Writers will write what they know… they're hardly obligated to use an unfamiliar measurement system for your convenience.

Well, it depends. If Atwood's aiming at an international audience, then he should use both measurement systems. If he's happy with an American audience then there's no reason for him to bother.

I note that the date of his blog post is the international-friendly “November 19, 2012” rather than the American numeric “11/19/2012”. But internationalising dates like this is easier than providing measurements in dual units.

Us Americans do use "Month DD, YYYY" quite frequently, so I don't think that his usage of it is done purposefully.

Indeed. MM/DD/YY is used informally and for datapoints (e.g. the Date field when you sign a form), but any time you are writing formally (e.g. a letter) you use Month DD, YYYY.

It's almost like MM/DD/YY is the abbreviation of "Month DD, YYYY"

XX/XX/YY is a terrible format and I wish people would stop using it.

01/02/03 can be January 2nd or February 1st, and often there's not enough context to determine which was meant.

Actually it can be February 3rd. I've seen YY/MM/DD format in use. But yeah it's horrible.

> If Atwood's aiming at an international audience, then he should use both measurement systems.

That, and also Atwood's popularity among American readers gives him a great opportunity to encourage them to use metric.

In the meantime, use http://news.ycombinator.com/item?id=4751410 :).

Try being British, you basically have to understand both intuitively.

I am British! I haven't used imperial for at least 15 years apart from for speed limits, which I ignore anyway.

Except you subconsciously have. All display sizes are sold in inches. The trip computer on your car will tell you miles per gallon. Even if you ignore speed limits, your speedometer gives you your speed in MPH :). If you've ever flown on a plane, altitude has been given as feet and distance in miles. So you do use both.

> If you've ever flown on a plane, altitude has been given as feet and distance in miles.

I've been on plenty of flights where displays and cockpit announcements were in metres (altitude) and kilometres (distance + velocity) - as well as Celsius for outside temperature.

True with display sizes although I'm interested more in resolution than size.

My trip computer does litres per 100km. I drive a Citroen C5 and it has kph on it as well as mph. My satnav usually reminds me if I'm driving too fast (in kmh which is handy) and that results only in me watching out for speed cameras and the fuzz :)

I don't fly - I drive if needs be. I frequently drive around Europe as it's easier than dealing with flights and a damn sight more comfortable, reliable and cheaper than flying. I can drive to Leipzig from London in about 10-12 hours.

> If you've ever flown on a plane, altitude has been given as feet and distance in miles.

If you fly a plane (not just on a plane), those are nautical miles, not land miles. And speed in knots. And rate of climb in ft/min.

>Except you subconsciously have. All display sizes are sold in inches.

I'm in a country that uses the metric system, and have never cared about learning the exact equivalent of screen sizes. I just intuitively know, (from using and looking at them in the office or the store) what a 13", 15", 24", 40" etc screen is like -- and I never bothered to do the conversion at all.

It wouldn't even really help, because even if a knew the measurement in metric units, it would mean very little to the actual feeling of the screen, especially considering the variety of aspect ratios and that the display size measures the diagonal.

>The trip computer on your car will tell you miles per gallon.

All trip computers I've even seen can be set to show metric units.

>Even if you ignore speed limits, your speedometer gives you your speed in MPH :)

Still no need to do any conversion. I've travelled thousands of miles in the US (Route 66 and coast to coast several times), and I never wondered "Hmm, how many km/h are 70 mph?". I just needed to keep an eye on the speed limit signs to keep below that, and drive as fast as the car/road called for. Intuitively, not by translating to metric units.

Having growing up in a metric country and lived in Britain I must admit its very nice having 60miles per equalling 60 minutes of driving for long trips.

Being able to say "I'm 45 miles away from X I'll be there in 45 minutes" without having to do recalculate each time you pass a road sign makes trips all the more pleasant.

The solution to that problem is simple -- drive at 60 KPH (37 MPH) instead of 60 MPH. :)

This would save gas too.

Actually it wouldn't in my Citroen C5. The fuel efficiency peaks precisely at 60mph/100kph. Something to do with the power transmission ratio.

I get 2.83l/100km or 83mpg in old money out of that if I don't drive like an asshat.

Yes,okay, I've heard stories like this so I cannot discount them. I find it hard to believe that a car could deliver better gas mileage at 60 MPH than at 37 MPH, unless there was something very strange about the number of gears and how they related to road speeds.

But ... there it is. There really are such cars out there.

It's more down to the sorts of roads. If you're doing 37mph it's usually in residential areas and extra-urban areas. These are notoriously full of traffic lights, other cars and humans which result in braking regularly and therefore costly energy sucking acceleration. Also engines are usually have peak energy transfer from fuel to distance at certain speeds due to gearing, revs, torque etc. This is by design.

If you're doing 60mph, you're probably on a relatively obstruction free A-road where the only energy required is to offset friction to maintain speed. I have driven from London to Leeds (195 miles) with not one single change in speed (apart from to take a piss and get a Burger King at Leicester Forest services!)

Also roads are a hell of a lot smoother and have less friction in Europe compared to the US. That makes one hell of a difference!

For ref, my car is a 1.9l diesel as well. These Citroen engines are super-efficient which is why I own it. I also have low rolling resistance tyres which make a 2-5% difference.

American cars are poorly designed guzzlers usually, even the ones they ship to Europe.

Or do 120 KPH and just cut the numbers in half.

This is quite convenient I'll agree but my satnav tells me how long it's going to take and bar traffic, it's quite accurate.

This principle is likely the reason imperial units stick: they're fantastic for fast fractional math. For the same reason, it's easier to work with 360 degrees in a circle than 2*pi radians.

>This principle is likely the reason imperial units stick: they're fantastic for fast fractional math.

As opposed to multiples of ten, in the metric system? Huh?

Draw a line that's a third of a meter.

Do it with a fifth of a yard ;-)

Like, 100/3 = 33 cm? That's supposed to be difficult?

Or do you mean that it's difficult to know how to draw a third of a meter?

Why, is drawing a line that's one meter, or one yard, or one foot any easier?

Without a measure I can't draw accurately any of them.

I guess they were referring to how a third of a yard would be a foot or 12 inches and that most people have an intuitive understanding of such common lengths. Also, because of the factors involved, “simple” fractions (e.g. ½, 1/3, ¼, ...) often end up at integral lengths.

But intuitive understanding of certain lengths is certainly not limited to the Imperial system. I frequently use A4 paper for measuring if I don't have a ruler at hand. I know the span between the tip of my thumb and pinky is pretty much 21 cm and so on. 8.2 inches probably wouldn't be much handier either.

You don't intuitively measure your weight in stone?

No - kilograms. Even my parents use Kg.

It's weird, because it is Imperial for some things,and Metric for others.

Temperature: Either

Building Materials: Metric

TV Sizes: Imperial

Beer: Imperial

Soft Drinks: Metric

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