Kilometre - Kick it into Touch

[bb21]

I remember in school when we had maths tests where we would have to give an estimated answer for an equation (in this case 12*50). I always took the time to work out the most accurate answer.

And promptly got the question wrong.

That is completely mad. Shows the worst of the education system.

 

[DaveNewcastle]

. . . .

And promptly got the question wrong.

We should always make allowances for people who makes errors when answering challenging problems.

But there's less room for allowances in getting the question wrong!

 

[Butts]

Yes, I'm thinking of one of the earlier ones from roughly around the 1970s; I tend to forget that most of the members on this forum are somewhat younger than my 47 years!







No, because I'm about 1m75 tall.

I understand weights in kg ( including my own! ) but seriously struggle with pounds, ounces and stones.

I can't believe this .....people quoting their height in CM and weight in KG

 

[bb21]

76 kilos does sound worse than 12 stones.

 

[Butts]

76 kilos does sound worse than 12 stones.

Another hangover() is women's bust sizes - have you heard of an 88cm DD

 

[PermitToTravel]

In the rest of the world, yes

 

[Liam]

Degrees are a pain in the backside. Radians are good but I feel they don't get wider use because it's hard to visualise multiplications of pi. Radians make a lot of sense - it avoids extra work in calculus and I believe in De Moivre's theorem.

There is an argument to use tau rather than pi.

1 tau = 2 pi
so, 1 complete revolution = tau = 2 pi
half a circle = tau/2 = pi
quarter circle = tau/4 = pi/2

 

[bb21]

Area of a circle?

There is a reason why tau has not taken off. It offers no distinctive advantage.

 

[306024]

I remember in school when we had maths tests where we would have to give an estimated answer for an equation (in this case 12*50). I always took the time to work out the most accurate answer.

And promptly got the question wrong.

Approximations were a valid part of the syllabus when I did my maths O-level, but then calculators were only just being invented (and steam hadn't long been phased out )

12 x 49 for example we were taught to do:
(12x50) - (1x12)
= 600 - 12
= 588

 

[DynamicSpirit]

There is an argument to use tau rather than pi.

1 tau = 2 pi
so, 1 complete revolution = tau = 2 pi
half a circle = tau/2 = pi
quarter circle = tau/4 = pi/2

I imagine that argument would evaporate very quickly as soon as you try differentiating sin x using tau!

More generally, noone has yet suggested that we move over to using natural units (h = c = e = 1)...
--- old post above --- --- new post below ---

Approximations were a valid part of the syllabus when I did my maths O-level, but then calculators were only just being invented (and steam hadn't long been phased out )

Are approximations no longer a part of the syllabus? (Genuine question - I don't know the answer).

It'd be a shame if they weren't. Calculators or no calculators, knowing approximations is incredibly useful for things like quick in-your-head estimates, or mentally checking whether the answer from a calculator is sensible.

 

[PermitToTravel]

Approximations are still taught and examined

 

[Liam]

Area of a circle?

There is a reason why tau has not taken off. It offers no distinctive advantage.

I totally agree, but when teaching radians to new learners it's far more intuitive that half a circle is half of tau.

For every example where tau works better, there are as many and probably more examples where pi works better.

 

[bb21]

They are more or less the same thing. I think it has a lot to do with the fact that pi is already well established. Had tau got in first, it may well have stuck.

 

[PermitToTravel]

My favourite reason to choose Tau, from the Tau Manifesto, is that e^iτ=+1
--- old post above --- --- new post below ---

I imagine that argument would evaporate very quickly as soon as you try differentiating sin x using tau!

There's no difference at all!

 

[Kite159]

I can remember when it was hot the temperature was reported in Fahrenheit as the numbers are bigger when it's cold it's reported in Celsius (again as -5 is better than ~30).

I'm part of the metric generation, although for mid to long distances it's still miles.

One measurement which should be updated is Miles per Gallon, to Miles per Litre (as it would make more sense, than the stupid "l/100km" measurement.

 

[jon0844]

The Daily Express always uses Fahrenheit. It's readership wouldn't even know what the metric system is. And if it did, it wouldn't like it.

Sent from my LG-D855 using Tapatalk

 

[GatwickDepress]

At school, barely four or five years ago now, we had these dog-eared textbooks from the 1980s full of questions to which you'd need a modicum of cricket and billiards knowledge in order to answer.

If the comments correlating national identity and a system of weights and measures are to go by, does this mean if Scotland goes independent they'll bring back the Scots mile?

I can't believe this .....people quoting their height in CM and weight in KG

Tell that to my GP!

 

[DownSouth]

L/100km is just as valid as mpg, what you prefer depends exclusively on what you grew up with.

I particularly like L/100km because it helps highlight the diminishing returns of spending a whole load of money to buy a slightly more efficient car, and because my fuel usage depends on the distance I drive rather than the other way around! It also has the advantage of there being no US and UK versions of the litre.

A similar deal applies to gradients. Whenever someone refers to a gradient using the idiosyncratic British "1 in n" form (why on earth would you want to measure flatness?) I have to mentally convert it into a percentage, but I'm sure the opposite applies to people in Britain who've never known different.
--- old post above --- --- new post below ---

If the comments correlating national identity and a system of weights and measures are to go by, does this mean if Scotland goes independent they'll bring back the Scots mile?

Is a Scots mile a longer version of the mile according to the extra distance walked by a drunk Glaswegian weaving about?

 

[bb21]

A similar deal applies to gradients. Whenever someone refers to a gradient using the idiosyncratic British "1 in n" form (why on earth would you want to measure flatness?) I have to mentally convert it into a percentage, but I'm sure the opposite applies to people in Britain who've never known different.

Now, is 1 in 2 twice as steep as 1 in 4?

Is 50% twice as steep as 25%?

 

[Butts]

L/100km is just as valid as mpg, what you prefer depends exclusively on what you grew up with.


Is a Scots mile a longer version of the mile according to the extra distance walked by a drunk Glaswegian weaving about?

No it's the number of convicts deported to Australia nose to tail in 1874

 

[BlythPower]

It's interesting that when 'metricating' their pints for both milk and beer, Australia rounded up. Here in the UK, we seem to have rounded down from 568ml to 500ml for both. For some reason a 500 ml carton of milk always costs more than a 1 pint/568ml one as well...

For me, my height and weight are imperial; distances are OK in either system; beer and milk come in pints and nothing less and fahrenheit is gibberish compared to the common sense of centigrade with its zero freezing point.

 

[Butts]

It's interesting that when 'metricating' their pints for both milk and beer, Australia rounded up. Here in the UK, we seem to have rounded down from 568ml to 500ml for both. For some reason a 500 ml carton of milk always costs more than a 1 pint/568ml one as well...

For me, my height and weight are imperial; distances are OK in either system; beer and milk come in pints and nothing less and fahrenheit is gibberish compared to the common sense of centigrade with its zero freezing point.

So you say - "oh it's so hot it must be in the twenties" ?

 

[BlythPower]

So you say - "oh it's so hot it must be in the twenties" ?

Who wouldn't? :?

Ice at 0 degrees, steam at 100 - what's not to like?

Fahrenheit on the other hand...

 

[Butts]

Who wouldn't? :?

Ice at 0 degrees, steam at 100 - what's not to like?

Fahrenheit on the other hand...

Anyone over 40 I suspect

 

[BlythPower]

Anyone over 40 I suspect

I'm 48.

 

[bb21]

We could all switch to using Kelvin. No nasty negative numbers to deal with.

 

[SS4]

Anyone over 40 I suspect

40 metric years? (don't ask me how it works). Kelvin sounds good to me

 

[ainsworth74]

Anyone over 40 I suspect

My mother would disagree and she's a firm believer in the imperial measures!

For me my height/weight is imperial but distances can be either (though long distance I tend to work in miles, short distances meters, centimeters and millimeters), volume and weight (other than mine) is metric but beer/cider/milk is in pints whilst speed is always MPH (or mach I suppose). Temperature has to be Celsius (but I'm not opposed to Kelvin) the Fahrenheit scale is, in my opinion, nonsensical...

 

[MidnightFlyer]

I will be totally honest here, I have absolutely no idea of how Fahrenheit works, it may as well be written in Russian for all the use it is to me. I am actually struggling to think of anyone I know who uses it.

 

[BlythPower]

My mother would disagree and she's a firm believer in the imperial measures!

For me my height/weight is imperial but distances can be either (though long distance I tend to work in miles, short distances meters, centimeters and millimeters), volume and weight (other than mine) is metric but beer/cider/milk is in pints whilst speed is always MPH (or mach I suppose). Temperature has to be Celsius (but I'm not opposed to Kelvin) the Fahrenheit scale is, in my opinion, nonsensical...

All the sensible people come from the North Riding.