Tuesday, September 23, 2008

How Many Ounces Are In A Pound?

Karen and I went to lunch today at the deli at Safeway.  Oh yes, eating at the grocery store.  You get a container and fill it with food and the price is $6.99 per pound.  I proceed to fill my container and then think I should weigh it to figure out where I stand.

The scale they provide next to the buffet is in ounces.  I place the container on the scale and it reads somewhere between 23 and 24.  Then it occurs to me that I have no idea how many ounces are in a pound.  I ask Karen and she can't remember.  I look at the scale and see it has units printed up to 30, so I'm guessing this scale can read up to 31.99 ounces or something like that.  Seeing the prices are per pound and the scale is small, I figure they are providing a pound scale.  So I guess that a pound is 32 ounces.

I would be wrong.  A pound is apparently 16 ounces.  I mention this here because it shows the failure of the imperial measurement system in use in the United States.  Everything is arbitrary and you have to memorize conversions.  I know 16 ounces are in a pound now, but I have no idea about any of the other weight measurements.  I'd have to look those up.

"But didn't you learn this in school?", you ask.  No.  I went to grade school in the 1980s and we were taught the metric system.  There was some coverage of the imperial system, but it was assumed that we would pick that up through everyday usage.  The thought was that we all needed to be ready for the big metric conversion.

"But you have to memorize metric conversions too!", you say.  That's true, but the big difference is the conversions are common across all measurements.  You only need to know 3 base units and then know the prefixes.  And it's base 10 too, so it's shifting the decimal point.  What are the three base units?
  • meter - This gives us a measurement for length.
  • gram - This gives us a measurement for weight.
  • liter - This gives us a measurement for volume.
There's also the second and the unit for temperature, but those can be discussed later. [The SI temperature unit is actually Kelvin, but all SI using countries use degrees Celcius for everyday use.]

OK, then you need to know the prefixes.  Kilo- is 1000.  Milli- is one thousandth.  Centi- is one hundredth.  All you're doing is shifting the decimal point.  And those prefixes are the same across the meter, the gram, and the liter.

I'd also like to point out that with metric being base 10, you never need to look at decimal values on measurements.  You can always shift to another prefix so that you are looking at a whole value.  Most people won't do this because you always want to see the same units for a particular task, but it's still valid.

The imperial system is arbitrary.  For length, we have the inch, the foot, the yard, the mile.  Others?  One inch is something, so that's the base I guess.  A foot is 12 inches.  A yard is 3 feet.  A mile is 5280 feet.  How many yards are in a mile?  How many inches in a yard or mile?  Wait, let me get a calculator.  You either memorize or do multiplication and division on a regular basis.  With metric you shift the decimal point.

Volume and weight?  I can't remember them all.  I know we have a US gallon which is 3.8 liters or 4 quarts.  A quart contains either 4 pints or 2 pints, I can never remember.  And then a pint contains some number of cups, I think.  And then the system is all messed up with the notion of fluid ounces.  Using ounce for something else!

Weight has pounds and ounces, I which I now know it's 1 to 16.  I know of nothing else for weight in this system.

We already use many things in the US that are metric labeled.  Coca Cola comes in 2 liter bottles, FDA labels on all food containers use metric measurements, prescription and over-the-counter drugs are sold in metric units, car engine displacement is in liters, injections are in "cc" units (cubic centimeter, which is a milliliter), IKEA manufacturers everything to metric dimensions, the entire automotive industry is metric, and the list goes on.

This is why I joined the United States Metric Association.  They seek to encourage metric usage in everyday measurements and in businesses.  They offer conversion assistance for individuals and businesses and explain what laws are currently on the books in the US.  Did you know you can do business exclusively in metric in the US and it's legal?

The goal is to encourage metric usage rather than forcing the conversion by law.  We all know that failed in the 1970s due to poor execution.

Get ready for more metric blog posts than you care to read.


KateGladstone said...

I look forward to your metric blog posts because I agree with you!

Virtual Llama said...

Great post! What you didn't add is that "imperial" measurements don't even match up with other countries that use it. US pints, quarts, gallons, fl oz and tons are all different to their British (and, I think, Canadian) counterparts!

Many of us Brits have the same experiences too. I have no idea how many oz in a lb or feet in a furlong, nor do I care to but I still have to drive in mph and drive under low bridges signposted in feet and inches despite my car being measured in mm!!!

Larry Werner said...

Indeed. Even car dealers from Long Island have to learn this by heart as well as how to measure a car's mileage.

Larry Werner