1. Base Units:
* The metric system has seven base units, representing fundamental physical quantities:
* Length: meter (m)
* Mass: kilogram (kg)
* Time: second (s)
* Electric current: ampere (A)
* Temperature: kelvin (K)
* Amount of substance: mole (mol)
* Luminous intensity: candela (cd)
2. Prefixes:
* To express larger or smaller quantities than the base units, prefixes are used. These prefixes are based on powers of ten.
* Common prefixes:
* Mega (M): 1,000,000 (10⁶)
* Kilo (k): 1,000 (10³)
* Hecto (h): 100 (10²)
* Deka (da): 10 (10¹)
* Deci (d): 0.1 (10⁻¹)
* Centi (c): 0.01 (10⁻²)
* Milli (m): 0.001 (10⁻³)
* Micro (µ): 0.000001 (10⁻⁶)
* Nano (n): 0.000000001 (10⁻⁹)
3. Derived Units:
* Many other units are derived from the base units using mathematical relationships. For example:
* Speed: meters per second (m/s)
* Area: square meters (m²)
* Volume: cubic meters (m³)
* Density: kilograms per cubic meter (kg/m³)
* Force: Newton (N) = kg·m/s²
4. Coherence:
* The metric system is designed to be coherent, meaning that derived units are directly related to the base units without any arbitrary conversion factors.
Key Features of the Metric System:
* Decimal System: Easy to convert between units by simply moving the decimal point.
* Simplicity: Fewer units and prefixes compared to other systems.
* Universal: Used in most countries worldwide.
* Scientific Basis: Based on natural phenomena and physical constants.
Example:
* 1 kilometer (km) = 1,000 meters (m)
* 1 milligram (mg) = 0.001 grams (g)
* 1 liter (L) = 1 cubic decimeter (dm³)
The metric system's simple and logical organization makes it easy to learn, use, and understand. It's a powerful tool for communication and measurement in science, engineering, and everyday life.
