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Welcome to Metric Mayhem: Quantity Prefixes.

• Before you begin make sure you know your base units (m, L, g, mol) and what they mean. Go here if you're unsure.
• You should also know how to write numbers using scientific notation.

Okay, there's not that much mayhem here... It's actually easier than the imperial system (aka the English System), but you have to treat a few things as fact to understand why:

Fact #1: Metric units are based on powers of ten. This means that if you start with 1 when you move the decimal you increase by a power of ten and if you move two places you increase by 100!

1.00 move one place to the right 10.0 Move another place to the right -> 100.

You also decrease by a factor of ten if you move the decimal to the left!

To understand spatially of what powers of ten actually look like check out this far-out, old school video below. Try to pay attention to the units on the side of the video to get the main idea, watching how big a power of ten is depending on what amount precedes it. Is each increase in power the same length as the power of ten before it? Find out!

Fact #2:

When you talk about something that means more than 10 (or less than 1) of something you add a prefix to the unit and take away the zeros. Prefixes come before the word.

Why? This is to keep numbers small so you write less and also to keep your calculations tidy and easy to follow.

Instead of saying I have 10 grams, you might say you have one dekagram. deka means ten. gram means you have 1 unit of mass.

Prefixes to know:

INCREASINGLY BIG UNITS

Kilo 1,000 of your base unit

Hecto 100 of your base unit

Deka 10 of your base unit

-- base unit = 1, example gram, liter, meter, mole

deci means 1/10 or .1 "decimal"

centi means 1/100 or .01 "There are 100 cents in a dollar, or 100 years in a century"

milli means 1/1000 or .001 "It takes a thousand years to make a millennium"

INCREASINGLY SMALL UNITS

Fact #3:

When you write an answer there are actually three parts to that answer. There's the number or the quantity you're talking about and then there is the unit which has a prefix and the type of unit.

Example:

3 cm or 3 centimeters

-3 is the amount

-meter is the type of unit

-centi is the prefix, which tells me that I have one hundredth of the unit that I am talking about. Centi literally means "hundredth."

In scientific notation here are your prefixes (click for clarity):

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Chemistry‎ <> ‎Chemistry Resources‎ <> ‎Introduction to Measurement‎