The metric system is a set of guidelines that lays out certain standards and common units for measurable quantities. The purpose of this system is to achieve uniformity, with regard to measurements, throughout the world.
Did you know?
On 23rd September 1999, the Mars Climate Orbiter spacecraft crashed into the surface of that planet. Investigations revealed that the disaster happened because a team involved in this project was using the imperial system of measurements, while others were using the metric system.
The modern metric system, formally known as the SI system (from the French ‘Le Système international d’unités’), developed as a result of the need to standardize all kinds of measurements across the world. Prior to this standardization, varied systems of measurement existed in different parts of the world. This led to a lot of confusion during activities, like scientific research. A large part of the world followed the imperial system, the system of measurements that originated in England. Almost all the countries of the world follow the metric system now. However, the United States still uses a system of units that is based on the imperial system.
Base and Derived Quantities
The metric system has established certain fundamental units for parameters like length, mass, and time, from which the other parameters (e.g., area, speed, density, etc.) are derived. The fundamental units are called the base units. The derived units are expressed in terms of the products of powers of the base units.
| Length | ||
| Unit | Conversion | |
| picometer | 1 m = 1012 pm | 1 pm = 10-12 m |
| nanometer | 1 m = 109 nm | 1 nm = 10-9 m |
| micrometer | 1 m = 106 μm | 1 μm = 10-6 m |
| millimeter | 1 m = 103 mm | 1 mm = 10-3 m |
| meter | base unit | base unit |
| kilometer | 1 m = 10-3 km | 1 km = 103 m |
| Weight | ||
| Unit | Conversion | |
| nanogram | 1 g = 109 ng | 1 ng = 10-9 g |
| microgram | 1 g = 106 μg | 1 μg = 10-6 g |
| milligram | 1 g = 103 mg | 1 mg = 10-3 g |
| gram | base unit | base unit |
| kilogram | 1 g = 10-3 kg | 1 kg = 103 g |
| metric ton | 1 g = 10-6 t | 1 t = 106 g |
| Area | ||
| Unit | Conversion | |
| square nanometer | 1 m2 = 1018 nm2 | 1 nm2 = 10-18 m2 |
| square micrometer | 1 m2 = 1012 μm2 | 1 μm2 = 10-12 m2 |
| square millimeter | 1 m2 = 106 mm2 | 1 mm2 = 10-6 m2 |
| square meter | base unit | base unit |
| square kilometer | 1 m2 = 10-6 km2 | 1 km2 = 106 m2 |
| Volume | ||
| Unit | Conversion | |
| cubic millimeter | 1 m3 = 109 mm3 | 1 mm3 = 10-9 m3 |
| cubic centimeter | 1 m3 = 106 cm3 | 1 cm3 = 10-6 m3 |
| cubic decimeter | 1 m3 = 103 dm3 | 1 dm3 = 10-3 m3 |
| cubic meter | base unit | base unit |
| cubic decameter | 1 m3 = 10-3 dam3 | 1 dam3 = 103 m3 |
1 liter = 1 dm3 = 10−3 m3
| Other Parameters | |
| Parameter | Unit |
| Time | second (s) |
| Speed | meter/second (m/s) |
| Temperature | degree Kelvin (°K) |
| Density | kilogram/cubic meter (kg/m3) |
| Force | newton (N) |
| Pressure | kilopascal (kPa) |
| Energy | joule (J) |
| Power | watt (W) |
| Luminous intensity | candela (cd) |
| Electric current | ampere (A) |
| Amount of substance | mole (mol) |
It is important, not just for people in science and commerce, but for everybody, to be familiar with this system, given the fact that it is used for making measurements all over the world. By doing so, a lot of unnecessary confusion can be avoided.