## Moving with Metric

**Liter Cube (FHWA-SA-94-018) Metric Basics:**

This box measures one tenth of a meter cube or 1 dm3 (cubic decimeter). If full of water, this cube holds 1 L (liter) and it’s mass is 1 kg (kilogram). 1000 L is 1 m3 (cubic meter), and its mass is one metric ton or 1 Mg (megagram); 1000 mL (milliliter) = 1 L; 1 mL = 1 cm3 (cubic centimeter), and its mass is 1 g (gram). 1 mm3 (cubic millimeter) = 1 µL (microliter), and its mass is 1 mg (milligram). Each side of the cube measures 1 dm (decimeter) and it is 4 inches minus 1/16 inch or exactly minus 1.6 mm (millimeter).

**LENGTH**

The basic unit of length is the meter (m) and should be used for all measurements: Short lengths - use millimeters (mm); Clothing and body measurements - use centimeters (cm); Long distances - use kilometers (km). 10 mm (millimeter) = 1 cm (centimeter); 100 cm = 1 m; 1000 m = 1 km (kilometer). One meter is 40 inches minus 5/8 inch or exactly minus 16 mm. One kilometer is 0.62 miles. One mile is 1600 m or more precisely 1609 m. Thus: ½ mile = 800 m; ¼ mile = 400 m; 1/8 mile = 200 m; 1/16 mile = 100 m.

## VOLUME

**Volume: **The SI metric unit of volume is the m3 (cubic meter). The liter (L) is a special unit for the measurement of liquids. A solid the size of this cube would have the volume of 1 dm3, but liquid filling this cube would have a volume of 1 L. 1 L = 1000 mL = 1 dm3 (cubic decimeter). 1000 L = 1 kL (kiloliter) = 1 m3.

## MASS

**Mass (weight):** Foods and other packaged goods will be measured in grams (g) and kilograms (kg).A kilogram is 2.2 pounds. A 175-pound person would have a mass (weight) of 80 kg. 1000 mg (milligram) = 1 g (gram); 1000 g = 1 kg (kilogram); 1000 kg = 1 t (metric ton) = 1 Mg (megagram).

## TEMPERATURE

TEMPERATURE Temperature: Water freezes at 0°C (degree Celsius); Water boils at 100°C.The Celsius scale is based on these two key conditions for water, and marked into 100 equal increments.

212°F (Fahrenheit) = 100°C = 373.15 K (kelvin)

104°F = 40°C

86°F = 30°C

68°F = 20°C

50°F = 10°C

32°F = 0°C

14°F = -10°C

-4°F = -20°C

-22°F = -30°C

-40°F = -40°C

-459.67°F = -273.15°C = 0 K – Zero point on the absolute temperature (kelvin) scale.

## HISTORY

**History:** The International System of Units (SI) is the dominant system of measurement units worldwide. Developed by the French in the late 18th century, the system has been refined by international agreement into the current SI format. Thomas Jefferson was the first proponent of the metric system in the United States. President Ford signed the 1975 Metric Conversion Act to require that Federal agencies use SI in their procurement, grants, and other business related activities. Many of you will remember the metric promotion in our schools in the 1970s, and the Liter Cube produced by the USDOT was a result of this act. The public opinion resisted the change to the metric system, and Congress passed an amendment to the Section 5164 of the Omnibus Trade and Competitiveness Act of 1988 (P.L. 100-418). Congress declared as USA policy that the metric system is the preferred system of weight and measures for trade and commerce. SI forms a logical, interconnected framework for the measurements needed in science, industry, and commerce. The system is built on seven base units. Multiples of ten allow the system to show large or small quantities with ease.