At a resteurant in Santa Cruz, California, I was about to order a plate of spare ribs. In the menu it said that the amount was "20 oz.". As an unprepared European I had no clue on what one oz. was. The bottle in front of me* contained 12 fl.oz, which I guessed was approximatly 1/3 liter. I needed some local help.

The waitress arrived my waving arm after a second (see: time messurement) looking very helpful. So I asked her: "How much is 20 oz?". She tried to show the size of the meal with her hands. That did not satisfy me. The shape she tried to show me was just that; a size. Which means; volume. And oz. was as I understood it a mass. If I needed a volume messurement, I would use fl. oz.

Since my vaitress was unable to forfill my request, I tried a new view of the problem and asked her: "What will you fill 1 fl.oz. with so that it will weigh 1 oz.?". This was obviously a Wrong Question(tm). So I tried a different angle: "How much will a cubic inch filled with water weigh?". Now she really started to look confused. Feeling I was on the right way, I hit her with another one: "How many fl.oz. goes into a cubic feet?"

After just a few more questions of this type, her face started to brighten, and she asked: "Is this maybe simpler in metric?"

My girl! She hit the nail right on the head. So I explained the essence to her.

1 meter = 1/10 millionth of the distance from equator to the pole**
1 meter = 10 decimeter = 100 centimeter
1 decimeter cubed = 1 liter
1 liter filled with water = 1 kilogram
1 meter cubed and filled with water = 1 metric ton

The waitres looked at me astonished and said: "But... Since it's so simple, why haven't we americans changed to that a long time ago?"
The only thing I could do was to return the question.

I got my meal, and now I know how much 20 oz. of spare ribs is; Enough to get full!

*) Not to be confused with Frontal Lobothomy.

**) Actually it is a ten-millionth of what some french guy in 1793 guessed what the distance was. But he got quite close.