12 April 2012

Going metric

The French invented it and you get to live with it

France is metric.  You won't see gallons of milk or °F or 2x4's or 65 mph.  So, what are we Yanks gonna do?  We adapt and go with the flow.  Of course, it's estimated that the US is already 40% metrified, what with the sciences, the multinationals, the military, and I don't know what else.

Confession: Even after more than ten years, I sometimes have to translate some measures into American units to "feel" them.  For example, 27 °C doesn't mean much to me.  To really sense what it means I have to do a quick conversion in my head to °F.  So, I've memorized some key numbers.  With these, quick approximations are possible.  YMMV (Your Mileage May Vary).  For this to work, you have to be able to do simple arithmetic in your head.

This post is about the common  measures you're most likely to run  into and the conversion factors to and from the equivalent American measures.

Warning: lots of numbers ahead!  A consommer avec modération. ("to be consumed with moderation", the phrase required on all public communications regarding alcohol)

  • Temperature
The easiest way to find the outside temperature is to look for a pharmacie.  They often have a brightly lit green sign sticking out over the sidewalk that alternates time and temperature.

Degree Celsius (°C) and degree Fahrenheit (°F):
Two pairs of figures to memorize: 20 °C = 68 °F and 5 °C = 9 °F.  The first pair is a conversion, the second pair adjusts.  From the adjustment pair we can see that a degree Celsius is almost 2 degrees Fahrenheit (1.8 to be exact).

How do I use these numbers?  Temperatures around here commonly fall in the range 10 °C - 30 °C.  That means I can start from my base of 20 and see how much and which way to adjust.  Say the temperature is 27 °C.  I see that 27 = 20 + 5 + 2.  So, I do the conversion using my memorized numbers and add together 68 + 9 + (2 * 2) to get 81 °F (80.6 °F in reality).

After you've memorized the conversion  pair above, you already know another pair.  If you reverse the 68, you get 86.  As it happens, 86 °F 30 °C.  And from middle school you already know 0 °C = 32 °F and 100 °C = 212 °F.  To finish, I've memorized two other pairs: 10 °C = 50 °F and 40 °C = 104 °F

To summarize:
                           °C              °F
                             0              32
                           10              50
                           20              68
                           30              86
                           40            104
                             5              9

How simple can it get? [chuckle]

Note: Some ovens in France use a temperature unit called gas mark (gaz thermomètre), which goes from 1 to 10.  I don't know anything about it.  Since our oven doesn't use it, I'll let you look it up if you're interested.

  • Time
This one's easy - no changes.  Seconds, hours, days, and so on - all the same in France.  Another time [no pun intended] I'll talk about timekeeping in France.

  • Distance
Centimeter, inch, and foot:
It's 2-1/2 centimeters to an inch (2.54 to be exact).  You double the inches and add half.  So, a foot or 12 inches becomes (2 * 12) + 6 = 30 cm.  Not difficult.  Going the other way is trickier.  A centimeter is about a 1/5 of an inch.  I have trouble working out quickly what is a fifth of 7 centimeters. [sigh]  OK, I can do 7 / 5 = 1.4 in.  But what is 0.4 in?

Meter and yard:
It's 39.37 inches to a meter.  Since a yard is 36 inches, a meter is 1/12th longer than a yard.  A first approximation is to add a tenth of the meters to the original number to get yards.  So, a soccer field of 100 meters is nearly 100 + 10 = 110 yards long.

Kilometer and mile:
Danièle taught me a mnemonic she used in her English classes.  A mile is a un ciseau neuf (a new chisel) kilometesr.  The pronunciation in French sounds like 1.609.   A first approximation is to add half the miles to the original number and round up a bit to get the kilometers.  So, 70 mi gives you 75 + 37 + a bit; in reality it's a little over 120 km.  The reverse conversion is 0.62, that is, a kilometer is 5/8ths of a mile.  A first approximation is to halve the kilometers and round up a fair chunk to get miles.  So, 100 km is 50 + a fair chunk; in reality it's 62 mi.

Note: When you're driving in France, you notice the kilometers fly by compared to miles!

  • Volume
Centiliter, fluid ounce, and cup:
Consumer quantities of liquids are typically measured in liters and centiliters (hundredths of a liter).  A can of Coke is 33 cl, a bottle of beer typically 25 cl, a glass of wine is typically 12 cl, a serving at a wine tasting is often 3 or 4 cl.  Since a fluid ounce is 3 cl, you triple or divide by a third to pass from one to the other.  You do remember that a cup is 8 fluid ounces?  Which makes a cup equal to 24 cl.  So, a bottle of beer is about 2 cups of beer and a glass of wine is about a cup.

Note:  You don't fill a wine glass more than about a third full.  Part of the pleasure of good wine is the smell and  you need the empty space to capture the aroma.  And that's why many wine glasses curve in slightly at the top.  I'll talk about not embarrassing yourself when drinking wine in France another time.

Liter, quart, and gallon:
A liter is slightly less than a quart (0.95 to be exact).  For all practical purposes you can equate the liter and the quart. Now, a gallon is almost 4 liters (3.8 to be exact).  Going the other way, a quart is slightly more than a a liter (1.06 to be exact).

Note: To convert the price of essence (gasoline) in France, purchased in liters and paid for with euros, to the price of gasoline, purchased in gallons with dollars, you need two additional numbers, the price of gasoline in euros per liter and the euro-to-dollar exchange rate.  Right now (12 avril 2012) the price of a liter of the gasoline we buy is 1.65€ and the exchange rate is $1.31 per euro.  You simply multiply together the three numbers: conversion factor (3.8), price per liter (1.65) and exchange rate (1.31), and you get a price per gallon of $8.21!  Ouch!!  Energy is expensive in France.

  • Weight
French recipes often call for weighed ingredients, American recipes rarely do.  Bring your American measuring devices if you plan to use American recipes.  Or you can use this site metric-US conversions by ingredient to do the conversions.

Gram and ounce:
An ounce is nearly 30 grams (28.3 to be exact).  So, you divide grams by 30 and round up a bit.  125 g is a tad over 4 oz (4.4 to be exact).

Kilogram, livre, and pound:
A kilogram is 2.2 pounds.  You multiply kilograms by 2 and and add a tenth of the result.  So, 10 kg is (10 * 2) + 2 = 22 lb.  Going the other way, a pound is a tad less half than a kilogram (0.454 to be exact or 454 grams). You take half the pounds and round down about a tenth.  So, 10 lb is (10 / 2) - 0.5 = 4.5 kg.

Une livre is not French for a book, but the French translation of pound.  It's 500 grams, not 454.  It's not uncommon to buy some things at the marché in livres - say a livre of Mirabelle plums.  Note that the weight is feminine, whereas the reading gadget is masculine.  Welcome to the French language!  (They say learning a foreign language is good for the brain!)

  • Exceptions
Even in France there are measures that aren't metric - bar, mille marin, nœud are the most common

Sometimes measured in bar (happens to be the same word in English- who knew?)  A bar is 14.5 psi.  Turns up when inflating tires.  Check the sidewall of the tire to find out how many bars of air to put in.

Nautical mesures:
Distance is measured in mille marin (nautical mile) and speed in nœud (knots).  A mille marin equals a nautical mile, about 1.15 miles.  A nœud equals a knot, about 1.15 mi/hr.

1 comment:

  1. Lots of good information here. Bravo again.
    But maybe you should point out that the French use the 24-hour clock. 4 P.M. is 16h.