Comment by svpk
3 days ago
I believe it's just a matter of intuitively useful units. There's simply too many seconds in a day for people to have an immediate grasp on the quantity. If you're using a space heater or thinking about how much power your fridge uses kilowatt hours is an easy unit to intuit. If you know you have a battery backup with 5 kilowatt hours of capacity and your fridge averages 500 watts then you've got 10 hours. If you convert it all to watt seconds the mental math is harder. And realistically in day to day life most of what we're measuring for sake of our power bill, etc. is stuff that's operating on a timetable of hours or days.
There are two types of jobs, the ones which require you to know that a day is about 8.5x10^5 seconds, and those which don't.
I use the conversion factor so often that I know it by heart: 1 day = 86400 seconds. I punch that 5-digit integer into a calculator, not an approximation like 8.5e5 (which is the same length, haha).
Is this sarcasm?
I'm not sure if I would call it sarcasm, but it's a reference to a popular computer science joke format.
The first time I saw it:
>There are 10 kinds of people in the world, those who understand binary and those who don't.
The joke is that 10 is how you express 2 in base 2.
I think there is another layer to the joke, though; often in mathematics, computer science, algorithms, and software engineering, things get divided into sets, sets get broken down into two sets according to whether some property about the elements is true or false, and this joke echoes that.
It's just meant to be silly.
True. Otherwise we would be using square meters for measuring gas mileage instead of miles-per-gallon (or litres-per-km) [1].
[1] https://what-if.xkcd.com/11/
Well, if you want to be pedantic, it's litres-of-fuel per km-driven. That doesn't cancel as nicely, if you don't drop the annotations.
Arguably, we should probably use kg-of-fuel (or mol) instead of litres-of-fuel anyway.
"litres-of-fuel per km-driven" (Volume/Distance) is still fully reductible to an area: litres is still a volume (1 cubic decimeter) and km is still a distance (1x10⁴ dm) Maybe you meant that the other way around? Distance/Volume (as in Miles/gallon) is an Area⁻¹ (Distance⁻²), which is more difficult to imagine in space.
Now, Kg is a measure of mass (or weight, depending on who you are asking), which throws density into the equation, which is proportional to the temperature, which will vary according to where and when the driving takes place. But since the time and place, and hence the temperature is (allegedly) defined when the fuel consumption was tested, the density is a constant, and as such you can leave it out from the relation.
Mass = V*ρ
(I know, I am being pedantic² :)
4 replies →
> miles-per-gallon (or litres-per-km) [1].
The UK is metric except for distance and beer.
So the disgusting ‘miles-per-litre’ is presumably needed too.
Also the UK gallon is different from the US gallon. And the same applies to all the other non-metric fluid measurements such as pints and fluid ounces. Historically the UK gallon was used throughout the former British Empire (Australia, Canada, India, Ireland, Malaysia, New Zealand, South Africa, etc). By contrast, almost nobody ever officially used the US gallon except for the US (and a small handful of highly US-influenced countries such as Liberia).
1 reply →
Meaning the ideal (cursed) unit of fuel consumption has units of 1/m^2