THE METRIC SYSTEM

September 9, 2012

WHY DO WE USE THE METRIC

SYSTEM?

Almost all other countries are using the

metric system

Other countries’ companies are refusing to

buy products from the U.S. if not labeled in

metric units

Scientists need a universal way to

communicate data (SI Units)

MATH AND MEASURING Math- the language of Science

SI Units – International System

MKS

Meter (m)

Mass (kg)

Time (s)

Prefixes plus base units make up metric system

Example:

centi + meter = centimeter

Kilo + liter = Kiloliter

THE METRIC SYSTEM MEASURES:Basic

Measurement

Definition Unit Abbrevi-

ation

Instrument Used to

Measure

Length Distance between two

points

meter m Meter stick,

centimeter

ruler

Mass Amount of matter in an

object

grams g Balance,

electronic or

triple beam

Time Interval between two

occurrences

second s Clock,

stopwatch

Temperature A measure of heat

intensity

Celsius

Kelvin

°C

K

Celsius

thermometer

Amount of a

Substance

The number of basic particles

of a substance in a gram

molecular mass of that

substance 6.02 *10 23 particles

mole M (mol) Balance

Derived

Measurement

Definition Unit Abbrevi-

ation

Instrument Used to

Measure

Volume Amount of space an

object occupies

liter L Graduated

cylinder

Density Mass per unit volume Grams/

Liter

g/L

g/cm3

Balance,

electronic or

triple beam

THE METRIC SYSTEM MEASURES:

Metric System Prefixes

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 ___________ 1 centimeter = _____ millimeters

Name Symbol Numerical

Value

Power of

Ten

mega- M 1,000,000 106

kilo- k 1,000 103

hecto- h 100 102

deca- da 10 101

Basic

Units

meters,

liters,

grams,

seconds

100

deci d 0.1 10-1

centi- c 0.01 10-2

milli- m 0.001 10-3

micro- µ 0.000001 10-6

Metric System Conversions

To go from a LARGER to a smaller prefix, move the

decimal point to the right

First write prefixes as powers of ten

Find the differences in powers of ten

Move the decimal point as many places to the right

as the difference in powers of ten

Example: 1.6 liter = _1600__ milliliters

Metric System Conversions

To go from a smaller to a LARGER prefix, move the

decimal point to the left

First write prefixes as powers of ten

Find the differences in powers of ten

Move the decimal point as many places to the left as

the difference in powers of ten

Example: 2.54 cm = _0.0000254_kilometers

Name Symbol Numerical

Value

Power of

Ten

mega- M 1,000,000 106

kilo- k 1,000 103

hecto- h 100 102

deca- da 10 101

Basic

Units

meters,

liters,

grams,

seconds

100

deci d 0.1 10-1

centi- c 0.01 10-2

milli- m 0.001 10-3

micro- µ 0.000001 10-6

TRY THIS USING THE

POWER OF TEN METHOD

1000 mg = __1___ g

Step 1: Determine if you are going from LARGER to smaller or

smaller to LARGER

Step 2: Determine the differences in powers of ten

Step 3: Move the decimal point the amount of places that was

determined in steps 1 & 2.

Name Symbol Numerical

Value

Power of

Ten

mega- M 1,000,000 106

kilo- k 1,000 103

hecto- h 100 102

deca- da 10 101

Basic

Units

meters,

liters,

grams,

seconds

100

deci d 0.1 10-1

centi- c 0.01 10-2

milli- m 0.001 10-3

micro- µ 0.000001 10-6

TRY THIS USING THE

POWER OF TEN METHOD

.15 L = ___150_____ ml

Step 1: Determine if you are going from LARGER to smaller or

smaller to LARGER

Step 2: Determine the differences in powers of ten

Step 3: Move the decimal point the amount of places that was

determined in steps 1 & 2.

DIMENSIONAL ANALYSIS

Allows one to change from one unit to

another

Units are always used in all calculations

RULES:

Set up equality in fraction form.

Lined up such that units used on the top

and bottom of neighboring fractions are

alternated so that units cancel.

Examples

Given: 1 in = 2.54 cm 1 ft = 12 in

How many cm are in 5 inches?

5 in × 2.54 cm = 12.7 cm

1 1 in

How many inches are in 27 feet?

27 ft × 12 in = 324 in

1 1 ft