World Metrology Day is celebrated annually on May 20, the anniversary of  the international agreement on units of measurement finalized at the Metre Convention in Paris, France in 1875.

World Metrology Day (WMD) commemorates the signing of the treaty and it is a day when all the countries in the world that enjoy the benefits of a single, coherent system of measurements, traceable to the International System of Units (SI), celebrate the scientific, technological, and economic achievements that this treaty has enabled for more than a century.

There are only 3 countries in the world that have not officially recognized the metric system: Liberia, Myanmar, and the United States.

Great news for students struggling to remember how many ounces in a pound, feet in a mile, or cups in a gallon. According to Elizabeth Gentry of the National Institute of Standards and Technology(NIST):

The United States is undergoing a subtle transition to the International System of Units (SI), commonly known as the metric system.

Learn about events in Gaitherburg, MD and Boulder, CO as well as celebrations around the world at the official WMD2009 site.

You were wondering: “What is Metrology?”

From Coastal Calibration Laboratories:

Definition 1): Metrology is the science of measurement.

Definition 2): Metrology is the science of weights and measures used to determine the conformance of an item to technical requirements. Metrology also includes the development of standards and systems for absolute and relative measurements.

Want to learn more about Metrology?

Only 3 more shopping days until Pi day.

In case you were seeking some music for your celebration:

Happy Pi Day

Happy Pi day to you,
Happy Pi day to you,
Happy Pi day everybody,
Happy Pi day to you.

(to the tune of “Happy Birthday”)

And there are more at this Pi day website. Be sure to check out all the mathematics and science songs at Greg Crowther’s site.

You missed the shipping date this year, but who says there’s a “season” for Pi shirts and aprons?

(Image via flickr user myklroventine)

From Yahoo news:

Dust off the slide rules and recharge the calculators. Square Root Day is upon us.

The math-buffs’ holiday, which only occurs nine times each century, falls on Tuesday — 3/3/09 (for the mathematically challenged, three is the square root of nine).

“These days are like calendar comets, you wait and wait and wait for them, then they brighten up your day — and poof — they’re gone,” said Ron Gordon, a Redwood City teacher who started a contest meant to get people excited about the event.

Be sure to get your fill of square carrots and radishes, there are only 6 left in this century:

1/1/01
2/2/04
3/3/09
4/4/16
5/5/25
6/6/36
7/7/49
8/8/64
9/9/81

Image via flickr user denaldo