Metric Conversions

Metric Conversions Unit – to - Unit

Quick Review • The Metric System uses a system of PREFIXES, which denote the valve of a number (placement of the decimal) combined with the type of measurement being made or the BASIC UNIT of measurement. The primarily used measurements can be expressed in three ways: length, volume, and mass. • Base Units: • Length = meter • Volume = liter • Mass = gram

Why Convert?

Why Convert? • Sometimes the number is too big… • 123,456 mm vs. 123.456 m • Which is easier to measure?

Why Convert? • Sometimes the number is too small… • 0.00985 kL vs. 9.85 L • Which is easier to measure?

Why Convert? • Sometimes the number is too big! • Sometimes the number is too small • Sometimes the your measurement includes a mixture of units – for example, the table is 1 meter and 47 centimeters long • After converting, you can say – The table is 1.47 meters long

Conversion – It’s Easy • We can use a technique called the Stair-Step Method • We need to know the prefixes from kilo- to milli- • We need to know where they go on the grid • We need to know the base units – liter, meter, and gram!

The Stair-Step Grid

Can You Remember the Prefixes? • Try a mnemonic! • King Henry Died Unexpectedly Drinking Chocolate Milk

Conversion – It’s Easy! • Do you know your left from your right? • Can you count to six? • Then you know everything you need to know to do the stair-step method!

Let’s Fill in the Grid

Metric Abbreviations • Most metric units are indicated by their abbreviations • Kilo - k • Hecto – h • Deka – da • Deci – d • Centi- c • Milli – m • Base units: meter (m), liter (L), gram (g)

Let’s Try a Sample Problem

Let’s Try a Sample Problem • Convert 12.54 kilometers to centimeters • 12.54 km = __________ cm • Ask – What direction do I move from kilometer to centimeters? • Ask – How many steps do I move from kilometers to centimeters?

Solution - Part 1 • Enter direction and number of steps

Sources of error • The problem – 1500 mL = _________ hL • Solution 1 – 1500 mL = 0.0015 hL • Solution 2 - 1500 mL = 150,000,000 hL • Solution 3 – 1500 ml = 0.015 hL (correct)

Sources of error • The problem – 1500 mL = _________ hL • Solution 1 – 1500 mL = 0.0015 hL (too many steps) • Solution 2 - 1500 mL = 150,000,000 hL (wrong direction) • Solution 3 – 1500 ml = 0.015 hL (correct)

The Solution • 12.54 km = ____________________cm • We move the decimal point 5 steps to the right. • We make a half circle under the problem each time we move. • We fill in above the half-circles with zeros. • 12.54 km = 1,254,000 cm

Metric Conversions