How do you read a metric ruler?

[jeremysterling]

...I have a few maxims in life, and one of them is you will be money ahead if you side with the Greeks.

The European Union is debating that maxim.

realolman already said it, but is true, most of our units of measurement are not friendly with thirds. Time on the other hand which is consistant in all measurement systems, is more friendly with thirds. 1/3 minute, 1/3 hour, 1/3 day all are easily converted to another unit without any rounding off being necessary.

The 360 degrees of the circle are thirds friendly.

Someone told me car engines with 5 cylinders are easier to design than 7 cylinders because 360 is fifths friendly as well

 

[PetrosA]

I spent 14 years in Europe. I have no problem whatsoever with meters, centimeters and millimeters - but it gets rougher with temperature when it comes to the weather. I'm fine with cold weather temps in C, but not warm weather temps. I know how my body will react at 95F but 38C is still fuzzy. All forms of metric make a lot of sense in the kitchen for me, either for weight, volume or temperature above 50C. I'm still completely clueless with body weights in kg - they just don't tell me anything - but food weights are fine. I guess it depends on what you have experience with.

There are some things here in the US that completely baffle me, like NOT using tenths of a mile on road signs even though it's the only way a driver can measure distance below one mile without doing math, or why we buy water and soft drinks in liters, but milk and juice in gallons - with the exception of gallon jugs of spring or distilled water...

 

[ActionDave]

The European Union is debating that maxim.

Need to edit and change that to Ancient Greeks.

 

[Besoeker]

Doesn't metric have something to do with numbers be divisible by 10 i thought i read that somewhere.

Not really and that's a common misconception.
It's a system of units with a single unit for each physical measurement or quantity.
The metre for length. Multiples and sub-multiples of the basic unit are decimal. Kilometre and millimetre for example.

You could do the same with Imperial if you picked just one unit for length, say the yard and ditch feet, inches, miles....
Then you could have the milliyard and kiloyard.
It's what we do with electrical quantities anyway. Volt, mV, kV, uF MΩ......etc

 

[don_resqcapt19]

I have often thought about getting my guys metric rules and tapes for running conduit. I think productivity would go up as you would not be adding and subtracting fractions which takes a bit longer than adding and subtracting whole numbers. I also think the scrap pipe would be smaller (even though it is very small now) as often the reason the conduit did not fit was because of a math error.
The use of whole numbers would be easier and the conduit doesn't care if you call it 127 mm or 5"

 

[Strathead]

The metric system would be so much easier as soon as we adjusted our thinking. When you learn a foreign language you start by interpretting everything in to your language, but eventually you start to think and process in the new language. The same would happen with metrics. Can you imagine trying to do math in roman numerals? The comparison is only marginally apt, but there is a comparison. using water as the basis for conversions, 1 gram=1cm cubed=1 ml and it take 1 kcal of energy to raise 1 gram of water 1 degree centigrade. What could be easier.

 

[kwired]

120819-1449 EDT

kwired:

Most computers are based on the binary number system.

2¹⁰ = 1024 decimal
1024d = 400h = 100 00000000b
2²⁰ = 2¹⁰ * 2¹⁰ = 1024d * 1024d = 1,048,576d

Why the binary system? Because it is easy, simple, inexpensive, and reliable to make bistable (binary) devices.

.

As well as computers use electronics so:
1 = on signal
0 = off signal

 

[don_resqcapt19]

The metric system would be so much easier as soon as we adjusted our thinking. ...

That is where the issue is. We don't adjust our thinking, we just keep converting from the metric system to our system and never adjust.

 

[Besoeker]

The comparison is only marginally apt, but there is a comparison. using water as the basis for conversions, 1 gram=1cm cubed=1 ml and it take 1 kcal of energy to raise 1 gram of water 1 degree centigrade. What could be easier.

Yes, that's one of the things I like about the SI - the way the units hang together. BTW, your 1 kCal should be 1 cal.

But there a few conversions that are not so directly obvious. Joules to calories or vice versa.
4.18J = 1 Cal.

 

[Besoeker]

That is where the issue is. We don't adjust our thinking, we just keep converting from the metric system to our system and never adjust.

I was brought up with the Imperial system and I think we may have had a few more than are commonly used in the US. As an example, for weights we had pounds and ounces of course but also the stone (14lb) the the hundredweight (112lb) the quarter which was quarter of a hundredweight.

I've been using SI for many decades and I don't recall any great problem adjusting to it - it generally being simpler. I imagine that a transition to Imperial for someone who previously only ever used metric could be a whole lot more difficult.

Another point is that most, if not all electrical units are SI derived units. There is no Imperial version of the volt, amp, watt.....
If we, in the electrical field, are obliged to use SI for a significant part of our calculations it would seem sensible to embrace them for all our calculations.

 

[kwired]

The metric system would be so much easier as soon as we adjusted our thinking. When you learn a foreign language you start by interpretting everything in to your language, but eventually you start to think and process in the new language. The same would happen with metrics. Can you imagine trying to do math in roman numerals? The comparison is only marginally apt, but there is a comparison. using water as the basis for conversions, 1 gram=1cm cubed=1 ml and it take 1 kcal of energy to raise 1 gram of water 1 degree centigrade. What could be easier.

Water is not a base for conversion it is just the base for most SI measurements. Now take same water to another planet and it will sort of mess things up, thing is grams is mass and not weight so if you look at it for what it really means a gram of water is still a gram of water on another planet but will weigh a different amount - weight is actually measurement of force which is newtons in SI units.

I would not be supirsed if even length (meters) isn't based on some standard amount of water and some other property of same water, like maybe a water column of 1 meter develops 1 k newton of pressure (IDK if true but would not be suprised at all if is or something that comes out at an even standard is what fits here.)

 

[Besoeker]

I would not be supirsed if even length (meters) isn't based on some standard amount of water and some other property of same water, like maybe a water column of 1 meter develops 1 k newton of pressure (IDK if true but would not be suprised at all if is or something that comes out at an even standard is what fits here.)

The newton is a measure of force rather than pressure which is the pascal.
1 Pa is 1N/m^2

 

[kwired]

The newton is a measure of force rather than pressure which is the pascal.
1 Pa is 1N/m^2

I knew newton was force, didn't give a lot of thought to pressure actually being a different unit -
although I have heard of the pascal.

But there again look at what SI has 1=1 and not 1=12, or 1=16, much simpler methods of base units and conversions.

 

[Besoeker]

But there again look at what SI has 1=1 and not 1=12, or 1=16, much simpler methods of base units and conversions.

I think it was designed that way.
Just the base units required. Everything else can be derived from those.

 

[jeremysterling]

I would not be supirsed if even length (meters) isn't based on some standard amount of water...

You're right! The standard of sea level!

From wikipedia:

Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole (at sea level).

 

[peter]

Just to get another tack to this thread:
My handydandy conversion table:
1 cm = 1/2"
1 liter = 1 quart
1 meter= 1 yard or 3 feet
1 gram = 1 paperclip
1 kilogram = 2 pounds
1 kilometer = 1/2 mile
Of course, none of this is accurate for trade but it should give you a general, ballpark estimate of what's going on.
~Peter

 

[ActionDave]

Inches aren't particularly thirds friendly either....

Divide the inch up into twelfths instead of sixteenths, like one side of a framing square, and you are good to go.

 

[Besoeker]

Just to get another tack to this thread:
My handydandy conversion table:
1 cm = 1/2"
1 liter = 1 quart
1 meter= 1 yard or 3 feet
1 gram = 1 paperclip
1 kilogram = 2 pounds
1 kilometer = 1/2 mile
Of course, none of this is accurate for trade but it should give you a general, ballpark estimate of what's going on.
~Peter

Agreed as rough estimates.

I'd take
1 cm as 0.4 inches and conversely 1 inch as 2 ¹/₂ cm
1 m as 40 inches.
1kg as 2lb then add 10%

For speed, 80kph is 50 mph.
Another convenient approximation is 1 foot is about 300mm.

 

[kwired]

Just to get another tack to this thread:
My handydandy conversion table:
1 cm = 1/2"
1 liter = 1 quart
1 meter= 1 yard or 3 feet
1 gram = 1 paperclip
1 kilogram = 2 pounds
1 kilometer = 1/2 mile
Of course, none of this is accurate for trade but it should give you a general, ballpark estimate of what's going on.
~Peter

Agreed as rough estimates.

I'd take
1 cm as 0.4 inches and conversely 1 inch as 2 ¹/₂ cm
1 m as 40 inches.
1kg as 2lb then add 10%

For speed, 80kph is 50 mph.
Another convenient approximation is 1 foot is about 300mm.

That is where the trouble is. The use of SI units is mathematically much easier to apply for most things. The fact that many have used other units for so long is what is hard about converting. People just can't visualize the differences and because of that have a tendency to block it. We are used to buying gasoline by the gallon, change the unit to liters and there will be many confused consumers. We are used to things in the construction trades being sized by the foot, yard, or inches.

If we would have used SI units 100+ years ago how many things would be slightly different in size today to be an even SI unit. or maybe at least a .50 SI unit? 4 foot wide panels are common in many construction products, they likely would either have been 1 meter or maybe 1.5 meters wide if we were using SI units years ago. I see 4 feet is 1.22 m. maybe they would make things 1.25 meters today IDK, that extra 3 mm might not seem like much but it does add up and becomes significant at some point. A lot of construction materials and methods are designed around a 4 foot standard or increments of 4 feet of material sizing, if they were designed around SI units everything would change to accomodate whatever a base size of common materials ends up being.

 

[Strathead]

That is where the trouble is. The use of SI units is mathematically much easier to apply for most things. The fact that many have used other units for so long is what is hard about converting. People just can't visualize the differences and because of that have a tendency to block it. We are used to buying gasoline by the gallon, change the unit to liters and there will be many confused consumers. We are used to things in the construction trades being sized by the foot, yard, or inches.

If we would have used SI units 100+ years ago how many things would be slightly different in size today to be an even SI unit. or maybe at least a .50 SI unit? 4 foot wide panels are common in many construction products, they likely would either have been 1 meter or maybe 1.5 meters wide if we were using SI units years ago. I see 4 feet is 1.22 m. maybe they would make things 1.25 meters today IDK, that extra 3 mm might not seem like much but it does add up and becomes significant at some point. A lot of construction materials and methods are designed around a 4 foot standard or increments of 4 feet of material sizing, if they were designed around SI units everything would change to accomodate whatever a base size of common materials ends up being.

An interesting concept. What are the standards for contruction in Metric Countries? For example, what is the distance between studs for the equivalent of our 16" OC or 24" OC? What is the standard sheet of sheetrock? What is the standard length of conduit?