Imperial and/or metric units. Discussion on the use and teaching of

[whole diary]

[DidcotPunter]

Quite interesting, I am 60 years old, when I first started school we only learned metric, even our rulers were only marked in centimetres, we were taught not to try converting to imperial all the time as by the time we left school nobody would be using it. It was not until I was about 10 that we started to regularly learn feet and inches in addition. Presumably an educational experiment that quietly went down the pan.

Interesting, I'm the same age. I started learning imperial at primary school but soon switched to metric. At grammar school I only learned metric too, never touched imperial other than for the odd mph in maths. This was early 1960s! Apologies for thread drift 

[JayMac]

I think we need to go easy here or one of our forum bosses will be splitting this off into a "Forum Members' ages and Units of Measurement" thread 

As you can see I've taken the veiled suggestion on board and split this discussion on units of measurement away from the Extending Crossrail to Reading topic.

bignosemac. Aged 41^. 5'10" and ?st ?lbs. 

[Red Squirrel]

As an aside to this aside, I'd like to take warmly by the throat the dimwit who decided to use the lower-case 'm' for 'miles' on motorway signs... apart from the confusion it must cause foreign drivers ('Services 15m' - Better hit the brakes then!) it will make things that much harder when, as must surely inevitably happen, the roads go metric.

[trainer]

The only line where dual speeds are sensible is HS1^▸ (High Speed line 1 - St Pancras to Channel Tunnel), so any foreign stock can use it without having to have a mph speedo fitted.

If I remember correctly my Video 125 programme on the Brussels-St Pancras run, HS1 does not have dual speed indication.  It's all in kph and the Eurostars are likewise speed calibrated.  Can't say anything about the 395s (Southeastern HST^▸ (High Speed Train (Inter City class 43 125 units))'s) and Class 92s or how they manage off HS1.  I'm sure someone on here will know.

The other comment is that many trains on NR^» (Network Rail - home page) are of 'foreign stock': Spanish, Italian and Japanese, immediately come to mind.

[Brucey]

41 years old here. And I did metric at skool.

However, ask me my mass in kilograms, or my height in metres, and I've no idea.

Early to mid twenties and I couldn't tell you my measurements in metric either.  Always done that in imperial.

I distinctly remember being taught both metric and imperial at school, even learning the 12-times table.

Working in science, I've been conditioned to using standard units (i.e. metric) for everything, but having to switch to the metric-imperial bodge of everyday life.  Metric is considerably more logical and it would be great if everything changed at some point in the future.

[LiskeardRich]

Tell that to anyone under 30 & they'll tell you they did metric at school

I'm 26 and did both, my maths degree specifically requires me to know conversion factors.

[stuving]

I know my university engineering course, starting an 1968, was the first in SI units. I think most universities would have changed over within a few years of then. Of course all the previous exam papers we used for practice were in medieval units - a bit of a shock in mechanics and thermodynamics, that. Fortunately there never had been any imperial electricity.

The history (Wikipedia and other) says metrication didn't really get going until after that, which is not how I remember it. But of course school science was all metric from much earlier, as I am sure it was in universities. That was cgs, so they still had to change over to SI (or MKS as it was called then) - though some physicists still haven't fully done that.

So we had imperial (and LSD) at primary school, for "life skills" (as it wasn't called), almost none at secondary school, and pre-1968 would have to re-learn some of that theory in imperial for an engineering course and career. Given that quite a lot of work contexts, as well as educational ones, have a mix of engineers and scientist by background, you can see why the impetus to change came from there. Doing calculations with a slide rule makes all those funny units a right pain, so the engineering professions were very keen to give that up.

Personally, I'd rather we did change over for units. That does not necessarily mean changing customary sizes, or only very slightly - that's a different matter. I have a feeling the biggest difficulty is the way certain newspapers promote the idea that all change is a form of dangerous alien infection, finding it helps to sell their product.

[JayMac]

So we had imperial (and LSD) at primary school,

Crikey! By the time I was at primary school we weren't even getting milk. 

[Red Squirrel]

My thermo-fluids lecturer at Bristol Poly insisted on using the gravitational FPS system, with the 'slug' as its fundamental unit. This was in 1978...

So here are two good reasons to use SI/metric units:

1. They are not insane. This makes them pretty unique among systems of measurement;
2. They don't carry the parapox virus.

[JayMac]

Can't say anything about the 395s (Southeastern HST^▸ (High Speed Train (Inter City class 43 125 units))'s) and Class 92s or how they manage off HS1^▸ (High Speed line 1 - St Pancras to Channel Tunnel).  I'm sure someone on here will know.

The Class 395 does have dual speed indication. On HS1 it uses the Transmission Voie-Machine (TVM^▸ (Ticket Vending Machine)-430) in cab signalling system which gives the driver a target speed to attain/maintain, along with a digital actual speed indication shown in km/h. When the Class 395 switches from HS1 to third rail for running on the 'classic' network the digital actual speed indicator switches to display the speed in mph. Drivers must then abide by lineside signals and speed boards.

I know this from 'driving' the Class 395 on the St Pancras - Faversham add-on for 'Train Simulator 2014'.  

Here's a video of the TVM-430 system in use on TS2014:
http://www.youtube.com/watch?v=YMRYb5ds1Cs

The switchover from km/h to mph is around the 17 minute mark at Ebbsfleet International.

[trainer]

The Class 395 does have dual speed indication.

I knew I wouldn't be let down!  And, like mine, such excellent academic sources. Thanks BNM.

[onthecushions]

My thermo-fluids lecturer at Bristol Poly insisted on using the gravitational FPS system, with the 'slug' as its fundamental unit. This was in 1978...

So here are two good reasons to use SI/metric units:

1. They are not insane. This makes them pretty unique among systems of measurement;
2. They don't carry the parapox virus.

The problems with the "old" units were that they did not well distinguish between mass and weight, (which is a force), producing oddities like the slug that you mentioned and its relatives the pound force and the poundal; also that they did not incorporate the first law of Tdics, so as to use the same unit for heat, work and energy, avoiding the BThU and the horsepower-hour.


That the metric system is as "Imperial" as it is  French is evidenced by the names of the units: Newton, Watt, Joule, Kelvin, Rankine etc.

It is still  a pity that so many commentators can't write units correctly (capitals for proper names, l.c. for multiples) and that power stations are rated in 1000's of homes powered. What is the conversion?

OTC

[Electric train]

and that power stations are rated in 1000's of homes powered. What is the conversion?

OTC

Ah the conversion to Watts is (number of 60W lamps in a house * the number of bedrooms / the number of WC^▸ (Wiltshire Council (Unitary Authority))'s) * the number of houses on an estate squared

If that doesn't come up with a sensible number or don't fit what you are trying to prove dream one up 

[Andrew1939 from West Oxon]

My father was a carpenter and I recall how he said that when he had a new apprentice straight from school he had to teach them and get them used to using imperial measurements now that they were in the real world. That was however many years ago but he also commented that sheets of plaster board were measured imperial one way (16 inches to fit into the standard gap between ceiling beams), and metric the other way. Subsequently they converted the 16" precise measure to a metric one going into (how many?) decimal places. Perhaps they have metricated the gap to a precise metric number now but what about the millions of homes built in the pre-metric age?

[stuving]

Subsequently they converted the 16" precise measure to a metric one going into (how many?) decimal places. Perhaps they have metricated the gap to a precise metric number now but what about the millions of homes built in the pre-metric age?

Not quite. Wickes catalogue lists standard baseboard as 1220x900 mm. Now 48" is 1219.2 mm, and plasterboard is soft enough for that to be an exact fit. In any case no house was ever built that precisely.  A few other board materials, such as loft flooring, come in that 1220 mm size.