(NIST: Gaithersburg, MD) -- Every day is a metric day at the National Institute of Standards and Technology (NIST). But that won’t stop the agency from celebrating Metric Week, held annually the week of Oct. 10—the tenth day of the tenth month.

This year marks the 34th annual celebration of Metric Week. Begun by the National Council of Teachers of Mathematics on May 10, 1976, approximately one year after the Metric Conversion Act of 1975, Metric Week serves as an opportunity for teachers, students, and the public to learn about the metric system, also known as the international system of units, or SI for short, and promote its use.

The U.S. government formally adopted SI, long the standard measurement system of science and engineering, as the preferred system of weights and measures for commerce and industry. Projects and plans created for the U.S. government use metric. According to Elizabeth Gentry, who serves as a metric coordinator at NIST, many, if not most, industries in the United States use metric units internally, to better serve international customers. Many manufacturers only perform conversions to U.S. customary units when packaging their products for domestic sale. Adoption of SI is voluntary and many products are sold with dual unit (customary and metric labeling) in the United States, but many countries only recognize the metric system and don’t allow products to be labeled with anything other than SI, requiring many industries to maintain separate inventories for domestic and international sale.

Based on units of 10, SI is very easy to learn, and many Americans know it better than they think. Many products, from bottled drinks to medicines, are already sold and conversed about in terms of their metric measures.

This year, representatives from the NIST Metric Program will be celebrating Metric Week with more than 4,000 students and teachers at the Science and Technology Education Partnership (STEP) conference in Riverside, California. Teachers and students who are interested in learning more about SI may download a variety of educational materials from NIST:

• Education Resources • Everyday Estimation • Metric Units of Measurement • Unit Conversions • Measurements in Sports

Teachers can also request a classroom set of SI educational materials by submitting their contact information and grade level to TheSI@nist.gov.

More information about Metric Week can be found at the National Council of Teachers of Mathematics (NCTM), NCTM Position - Teaching the Metric System for America’s Future, National Science Teachers Association (NSTA) Position - Use of the Metric System, and the U.S. Metric Association - Metric Week.