The International System of Measurement

Also Known as

The Metric System

System International

Metric System

• Simple to use• Based on units of ten• Easy to make conversions• Used by all scientists• Used in the medical field• Used in most countries• Can be easily learned in an hour

Units of measure

Metric Units

MeterMeasures distance

or length

LiterMeasures volume

(such as water)

GramMeasures mass and

weight

Metric Notes• Meter – measures units of distance or length

• Liter – measures units of volumes or liquids

• Gram – measures units of mass or weight

More notes…

• There are no commas in the metric system• There are no fractions in the metric system• When the liter symbol is hand written, it must be a

capital letter so that it is not confused with a one. When it is with another symbol, lower case can be used. Ex. L stands for liter, and ml or mL both mean milliliter.

• Metric temperature is Kelvin. Celsius is a more common form of metric temperature, because it is derived directly from the Kelvin scale. On the Celsius scale, water freezes at 0°C and boils at 100°C.

Make a scale for conversions…

• Make a row of seven boxes across your paper like this:

• Use prefixes to fill in each box left to right from greatest to smallest. Start with kilo- on the left and end with milli- on the right.

• Make sure they are in order and unit is in the center box.• Put the symbol below the box and the number it

represents above the box.

Your scale should look like this…

1000 100 10 1 0.1 0.01 0.001

k h da or D d c m

kilo hecto dekaUnit

(meter,Liter, gram)

deci centi milli

Converting in Metrics

1. Identify the position of the decimal. If there is no decimal, it is at the end of the number. Put your pencil there.

2. Identify the location of prefix (or lack of, meaning the unit of meter, liter, or gram) on the metric scale. Put your index finger there.

3. Identify the new position (where the new prefix is located).4. Determine whether you need to move right or left.5. Determine how many times you need to move to get there.6. Move the decimal the same number of times and in the

same direction.

Remembering this can be hard

So..here is a way to help remember prefixes

• Kids- kilo• Have- Hecto• Dropped- Deca• Over (base unit: gram Or liter Or Meter)• Dead-Deci• Converting-Centi• Metric- Milli

Let’s practice

• Write this problem down

• 3.4m = cm1. put your pencil on the decimal (.)2. Put your finger on (units) where m would be3. Move your finger right 2 times to cm.4. Move the decimal right 2 times.5. Fill in missing spaces with zeros

Did you get this answer?

• 3.4m = 340cm

• Let’s try another.

• 500mg = g • Use the same procedure. Put your pencil on

the decimal and your finger on the corresponding space and move.

Ready…Set…Move…

• 500mg = g• Move your finger 3 times to the left then

move the decimal 3 times to the left.• Did you get…

• 500mg = 0.5g

One more time…

• 0.2kL = L• Pencil on the decimal and finger on the chart.• Count 3 right then move the decimal 3 right.• Did you get…

• 0.2kL = 200L

That was easy…

• Practice just a few then check your answers with a friend.

• 3.5cm = mm• 500mg = g• 2L = mL• 0.25km = m

Check your answers

• Did you get…

• 3.5cm = 35mm• 500mg = 0.5g• 2L = 2000mL• 0.25km = 250m

Now all you have to do is practice, practice, practice……………

A few more notes

• Metric units of volume can be converted to cubic centimeters, cc, or centimeters cubed, cm3, very easily

• Step one…convert to milliliters (mL).• Step two…milliliters are equal to cubic

centimeters and to centimeters cubed.• mL = cc = cm3

Let’s practice

• 23mL = cc• 23mL = 23cc

• 55cc = cm3

• 55cc = 55cm3

Just one tough one

• 0.7L = cc

• First convert to mL• 0.7L = mL• You get 700mL• Then 700mL = 700cc