Metric System Basics
Karen Storey
WSPA
7 th Grade Science 9/9/13

Metric System
• The metric system is based on a base unit that corresponds to a certain kind of measurement
• Length = meter
• Volume = liter
• Weight (Mass) = gram
• Prefixes plus base units make up the metric system
– Example:
• Centi + meter = Centimeter
• Kilo + liter = Kiloliter

Metric System
• The three prefixes that we will use the most are:
– kilo
– centi
– milli kilo hecto deca
Base Units meter gram liter deci centi milli

Metric System
• These prefixes are based on powers of 10.
What does this mean?
– From each prefix every “step” is either:
• 10 times larger
or
• 10 times smaller
– For example
• Centimeters are 10 times larger than millimeters
• 1 centimeter = 10 millimeters kilo hecto deca
Base Units meter gram liter deci centi milli

“Staircase” Method
Draw and label this staircase every time you need to use this method, or until you can do the conversions from memory

Converting From Standard to
Scientific Notation
• Move decimal until it is behind the first sig fig
• Power of 10 is the # of spaces the decimal moved
• Decimal moves to the left, the exponent is positive
• Decimal moves to the right, the exponent is negative
– 428.5  4.285 x 10 2
(decimal moves 2 spots left)
– 0.0004285  4.285 x 10 -4
(decimal moves 4 spots right)

Converting From Scientific to
Standard Notation
• Move decimal point
• # of spaces the decimal moves is the power of 10
• If exponent is positive, move decimal to the right
• If exponent is negative, move decimal to the left
– 4.285 x 10 2  428.5
(move decimal 2 spots right)
– 4.285 x 10 -4  0.0004285
(decimal moves 4 spots left)