Metric System

History  At the end of the 18 th century, scientists created the metric system.  In 1960 at the International Convention, the metric system was adopted as the “International system of Units” or SI.  SI is based on units of ten.  Using the same system of measurement gives scientists a common language.

Who uses the Metric System? SCIENTISTS Every country EXCEPT the United States. The US uses the English unit of measurement.

Length The basic unit of length in the metric system is the meter (m) The meter is = to 39.4 inches

Volume Volume is the amount of space an object takes up. The basic unit of volume is the liter (L) The volume of solids can be measured in cubic centimeters (cc) = a cube that measures 1cm x 1cm x 1cm 1cc is exactly equal to in volume to 1 ml

Mass Mass is a measure of the amount of matter in an object The basic unit of mass is the gram (g)

Weight Weight is a measure of the attraction between two objects due to gravity Your weight on another planet may differ due to the amount of gravity, however your mass will always be the same

Density The relationship between mass and volume is called density Density is defined as the mass per unit volume of a substance. Density = Mass Volume

Temperature In the metric system, temperature is measured on the Celsius scale. On this temperature scale, water freezes at 0 o C and boils at 100 o C. The metric system was set in such a way that there was exactly 100 degrees between freezing and boiling point of water. Normal body temperature is 37 o C. Room temperature is about 21 o C.

Conversion

How can you remember this?

How do you convert from one unit to another? For every space that you move you move the decimal one place to the left or the right K – H – D - - d – c - m

A Sample Problem… 3.45 Kg = _____g K – H – D - - d – c - m

Another Sample Problem 756 ml = ______L K – H – D - - d – c - m

Dimensional Analysis Dimensional Analysis is another way of converting units. It is often used to convert units from English to Metric or vise versa. Your friend in England runs 3 kilometers a day while you run 300 yards a day. Using kilometers which of you runs a longer distance?

Steps for Dimensional Analysis Step 1: Determine the given unit and the desired unit. Given: yards (300) Desired: kilometers

Step 2: Find the relationship between the units and consider the possible conversion factors Known: 12 inches / 1 foot 1 yard / 3 feet 2.54 inches / 1centimeter 100 centimeters / 1 meter 1000 meters / 1 kilometers

Step 3: Choose the conversion factor whose denominator has the same units as your given value to start with. Start with 1 yard 3 feet

Step 4: Write the original value next to the conversion factor with a multiplication sign between them. Cancel like terms. 300 yds x 3 ft x 12in x 2.54cm x 1m x 1km 1yd 1ft 1in 100cm 1000m

Step 5: Multiply the resulting equation. 300 yds x 3 ft x 12in x 2.54cm x 1m x 1km 1yd 1ft 1in 100cm 1000m 1) Multiply across the top:27,432 2) Multiply across the bottom: 100,000 3) Divide top by bottom: km

Solution to equation 300 yards = km which is less than 3km. Therefore your friend in England runs more than you do per day.