Metric System of Measurement

(Correctly called "SI")

The metric system is a system of measuring. It has three basic units:

m		the meter for length
kg		the kilogram for mass
s		the second for time

With those three simple measurements
we can measure nearly everything in the world!

Larger or Smaller

But what if we want to talk about really big or really small things?

Answer: we can use Metric Number Prefixes

• like "kilo" (a thousand)
• and "milli" (one thousandth)
• and so on

Example: something that is 1,000 meters is a "kilometer"

Something that is one thousandth of a second is a "millisecond"

In fact the kilogram already uses this method, because it is a thousand grams, a kilogram.

So one thousandth (1/1000) of a kilogram is simply a "gram"

Here is a quick summary of the special prefixes:

Large Numbers

Name	deca	hecto	kilo	mega	giga	tera	peta	exa	zetta	yotta
Symbol	da	h	k	M	G	T	P	E	Z	Y
Factor	101	102	103	106	109	1012	1015	1018	1021	1024

Example A million liters would be called a megaliter and abbreviated ML

Small Numbers

Name	deci	centi	milli	micro	nano	pico	femto	atto	zepto	yocto
Symbol	d	c	m	µ	n	p	f	a	z	y
Factor	10-1	10-2	10-3	10-6	10-9	10-12	10-15	10-18	10-21	10-24

Example A thousandth of a second would be called a millisecond and abbreviated ms