Metric vs Imperial VS USA measurements

[leehljp]

I probably have seen different ones of you reference this and it probably just went over my head. Loring probably referenced this in the past, but again - probably because I was in Japan and the metric system was more directly referenced against the imperial system of England, which is not necessarily the USA system

I was looking up the weight of a gallon of water. In England it is 10 lbs. In the USA it is 8.3 (I always thought it was 7.5) but that was two generations ago when I learned my "system".
http://www.answers.com/Q/How_much_do...of_water_weigh

At the link, I saw that the "Imperial" is not the same system we use in the USA.

So what part of our weights and measurements IS Imperial and what is NOT Imperial? What is our System called?

Just remembered: 7.5 lbs is the approx weight of a gallon of gasoline (USA weights and measurements), I think.

[Tom Slick]

We use US Customary units

http://en.m.wikipedia.org/wiki/United_States_customary_units

The metric system is part of the International System of Units (SI)

[cwsmith]

In my writing for instruction manuals, I used to refer to the U.S. measurements as "U.S. Customary" vs "SI Metric". That was in the 70's and early 80's when the company was pushing to have it's technical publications "metricized". When I went to another division in the mid-80's, they didn't bother and just kept all measurement as U.S. Domestic. (Same as "Customary")

As you mentioned, there are differences between U.S. Customary units and Imperial units. Likewise, there are differences between in European nations using Metric. The "SI" standard is sort of an adaptation to what the International Standards Committee arrived at. One example that comes to mind is the measurement of pressure. In the U.S. we use PSI or PSIG depending on the application. In the UK the measurement was in kg/cm and in France they used the "bar". For Si standards the measurement of pressure is the "bar".

CWS

[atgcpaul]

For water, I've always used "a pint is a pound, the world around" from Alton Brown. 8 pints in a gallon so 8 lbs (or thereabouts)

Since I work in a lab and use SI units for measurement, I also know that 1L of water equals 1kg (at 4deg C, but close enough at room temp). 1kg equals 2.2lbs. I also keep in my head that 3.79L equals 1 gallon. So doing all that math, 8.3lbs for 1 gallon.

[leehljp]

"US Customary Units" - I learned something today!


I can use metric weights and length without a problem, and interchange back and forth with "US Customary Units" without a problem also; But for some reason I always thought the British Imperial Units was the same that the US used.


A couple of weeks ago, I was across the State (MS) helping a church being renovated. For some reason I have found that most carpenter, painters, contractors (even mechanical engineers) and DIY folks at church rebuild/renovation ignore me on building projects and it is hard for me to offer a helping hand at the things I am good with. Two guys (one was DIY guy and salesman and the other was a retired auto mechanic) These fellows were trying to put a somewhat large multi-layered wood train table together. I asked if I could help. They said I could watch. The screws were metric and marked as metric. They kept saying - I need a 42mm, or an 18 mm, or a 30mm screw or 8mm. I started telling them "42 - Get the 1 1/2 in"; or "18 - get the 3/4 inch; "30 get the just over 1 inch; "8mm get the 5/16"

They looked at me, picked up a screw measured it and asked "How do you know that?" Me: "Because it is!" "Picked that up in High School 50 years ago". They looked at me like was weird or something. At that point they let me in to help!

[tfischer]

Oddly enough, there's a Wikipedia article about this:

https://en.wikipedia.org/wiki/Comparison_of_the_imperial_and_US_customary_measurement_systems

[cwsmith]

Lee,

I know the feeling about being "ignored". I'm certainly not the sharpest knife in the drawer, but I do have a lot of experience and I remember things very well. Still I've noted that many people, in certain vocations have a tendency to dismiss others all to easily. Yet, over the years I've been able to introduce some designs and engineering ideas that simply come from thinking a project thru. I joke that I don't have the disadvantage of being educated to the point where I don't know that it can't be done.

Always good to hang in there and just forgive those who don't know you that well.

CWS

[leehljp]

Lee,

I know the feeling about being "ignored". I'm certainly not the sharpest knife in the drawer, but I do have a lot of experience and I remember things very well. Still I've noted that many people, in certain vocations have a tendency to dismiss others all to easily. Yet, over the years I've been able to introduce some designs and engineering ideas that simply come from thinking a project thru. I joke that I don't have the disadvantage of being educated to the point where I don't know that it can't be done.

Always good to hang in there and just forgive those who don't know you that well.

CWS

You made me laugh. I am a Myers Briggs INTP - the " I " is for "introvert" but my work requires me being extrovert. I do the extrovert thing fairly well but don't push it. Because everyone who knows my ministry related work (at introduction) before getting to know me personally, they tend to thinks of me as a "pastor," and as such, they think I don't know how to do anything! Sometimes that is a good thing and I just play along.

What made me laugh about your post was that on several occasions I told several small individual Japanese church groups, over time, how much advantage they had over me. I would say: "I have a post graduate degree. I tend to depend on books and my seminary teachers, but you depend on someone far more powerful than all these theology books and a well educated men. There is No comparison." They got the message. And on this same thought, I have watched education get in the way of common sense and reason and logic far to often.

I am generally an "observer". I don't go "looking" for things to observe, but when something out of the ordinary (people, culture, mechanical, electrical, etc) occurs a couple times, I quickly make a mental note and question if a pattern is happening (INTP again). I usually compare mentally my "discoveries" vs the norm. (just a mental thing for me) In my years of meeting Japanese on different levels, I discovered quite a few Japanese who didn't actually finish college. (I didn't know why, though.) Then our organization did a fairly detailed study on real Japanese culture vs perceived cultural circumstances - what we thought was normal. I made the statement that Japan had much less college grads than we thought. Everyone thought I was crazy. After the study, it was somewhere close to 40% of college entrants did not graduate. Japanese companies (this was back in '93-94) at that time would put on "job fairs" at colleges/universities and hire away the best students 1 to 2 years before they graduated. The companies did not want the students to get set in their "educated - academic" ways, and wanted to train the students to think in the way of the company. Companies learned that at some point Japanese students would become more "academic" minded than deductive reasoning minded. I don't know if companies still do this or not.

[LCHIEN]

Today's standard systems are the Metric SI system and the US customary system; the latter being what is commonly used in the US.
What is called the imperial system was legislated in England in 1824 after the US revolutionary war and before England joined the metric system in 1995 (but imperial units are still dual marked often and used outright for certain items (highway signs showing distance). The imperial system used many of the old mile/foot/inches etc stuff but some was different.
Since we were no longer part of England we did not adopt the Imperial system.
Anyway that's where imperial gallons comes from.

Sometimes Imperial gallons is called UK gallons. In international circles the US Gallon has the "US" prefixed to it to avoid confusion. Also there is a US Dry gallon for dry measure.

The U.S. liquid gallon is defined as 231 cubic inches and equates to approximately 3.785 litres. One imperial gallon is equivalent to approximately 1.2U.S. liquid gallons.
A US Gallon of water weighs approximately 8.34 pounds; the exact value depends on the specific density of the water which is a function of the temperature of the water!.

Gasoline can be made up of a number of different hydrocarbons providing the correct octane rating. So the weight of a gallon of gasoline is quite variable. I just use 7 lbs for estimation purposes.

I found the following summary on the internet:


A gallon has 3 different, commonly used, definitions [1].

Imperial (UK) Gallon

The imperial (UK) gallon was originally defined as the volume of 10 lbs of water, and is now defined as exactly 4.54609 L, which is 10.02 lbs of water at its densest (2.20456 lbs / L at 4 °C or 39 °F [2]).

US liquid Gallon

The US has two different definitions of the gallon, the most commonly used one is the 'liquid' gallon, defined as a volume of 231 cubic inches or 3.785 L. This comes down to 8.344 lbs of water at its densest.

US dry Gallon

The other definition in use in the US is the 'dry' gallon, defined as 1/8th of a US Bushel, totaling to exactly 268.8025 cubic inches or 4.405 L. This amounts to 9.711 lbs of water at its densest.