The Metric System

The Metric System

Length

• The metric system is an international system of measurement.

• All sciences use the metric system.

• The United States is the only industrialized nation in the world that does not use the metric system as their official measurement.

• Even though it is not our official system of measurement, we still use the metric system in various aspects of our lives.

Metric System• The three prefixes that we will use

the most are:– kilo– centi– milli

kilo hecto deca

Base Units

metergramliter

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

metergramliter

deci centi milli

Metric System

– Centimeters are 10 times larger than millimeters so it takes more millimeters for the same length

1 centimeter = 10 millimetersExample not to scale

1 mm

1 mm

1 mm

1 mm

1 mm

1 mm

1 mm

1 mm

1 mm

1 mm

1 cm

40

41

41

40

Convert 4cm to mmYou are moving right 1 step so you multiply by 104 x 10 = 404cm = 40mm

Convert 5m to cmYou are moving right 2 steps so you multiply by 1005 x 100 = 5005 meters – 500 cm

Convert 34 mm to cmYou are moving left 1 step So you divide by 1034 ÷ 10 = 3.434 mm = 3.4 cm

Convert 34 mm to mYou are moving left 3 stepsSo you divide by 100034 ÷ 1000 -= .03434 mm - .034 meters

kilo hecto deca

meterliter

gramdeci centi milli

Move right : multiply by a power of 10 for each step

Move left: divide by a power of 10 for each step.

Metric System• Now let’s start from centimeters and

convert to kilometers

400000 centimeters = 4 kilometers

400000 centimeters = 4.00000 kilometers

kilo hecto deca

meterliter

gramdeci centi milli

Metric System• Now let’s start from meters and convert to

centimeters

5 meters = 500 centimeters

kilo hecto deca

meterliter

gramdeci centi milli

kilo hecto deca

meterliter

gramdeci centi milli

• Now let’s start from kilometers and convert to meters

.3 kilometers = 300 meters

You Try:

8 m = _____cm 92 cm = _____mm120 cm = _____m 150 m =______km44 mm = _____mm 7 km = ______m

Move right : multiply by a power of 10 for each step

Move left: divide by a power of 10 for each step.

kilo hecto deca

meterliter

gramdeci centi milli

Metric System• Summary

– Base units in the metric system are meter, liter, gram

– Metric system is based on powers of 10– For conversions within the metric system, each

“step” is 1 decimal place to the right or left– Using the diagram below, converting to the

right, moves the decimal to the right and vice versa

kilo hecto deca

meterliter

gramdeci centi milli

Reading a Metric Ruler

All metric rulers are numbered with centimeters (although they may show mm, cm, or metric)

The longer lines on the metric ruler are called…

• centimeters

The shorter lines on the metric ruler are called…

• millimeters

To read in centimeters write down how many whole centimeters and then each line after is .1 of a centimeter.

Arrow A above is one line past 12 centimeters therefore it is 12. 1 cm.

Arrow B is four lines past 15 centimeters therefore it is 15.4 cm

A B

If you needed to measure in millimeters it is easier to measure in centimeters first and then convert to millimeters by multiplying by 10.

Arrow A is 10.7 cm = 107 mmArrow B is 14.1 cm = 141 mm

A B

______cm ______mm

______cm ______mm

______cm ______mm