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The Metric System. All our measurements will be done using the metric system. Some are familiar to you, some are not. Large bottles of soda Large containers of milk Speed limits Distances from city to city. Type of measurement Basic Unit Length meter Mass gram Time second
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All our measurements will be done using the metric system. Some are familiar to you, some are not. Large bottles of soda Large containers of milk Speed limits Distances from city to city
Type of measurementBasic Unit Length meter Mass gram Time second Volume liter Notice that basic units don’t have any prefixes.
What if you wanted to measure the width of your finger? What measuring device would you use? A ruler, of course. Would you report the width as a part of a meter? (That’s the basic unit of length.) A smaller unit would be more convenient—like what?
How about a centimeter? It’s about as big as the width of your finger. There are 100 of them in a meter. One hundred cents in a dollar. One hundred years in a century. Do you see the pattern?
Suppose you want/need to convert from centimeters (cm) to meters (m)? This method will work for any metric to metric conversion, either bigger unit to smaller or smaller to bigger.
METRIC PREFIXES kilo = K centi = c milli = m Prefix Basic new unit Kilo gram Kg centi gram cg milli gram mg Kilo meter Km centi meter cm milli meter mm
Don’t get the first “m” mixed up with the second “m” in mm. First one is for … Second one is for … The first letter is always the prefix. The second letter is always the basic unit.
The metric system is based on multiples of 10. So, to convert from one prefix to another, you need to multiply by factors of 10 or divide by factors of 10. Sound complicated?
Put the prefixes in order: Unit can be any basic unit:like meter, gram, liter
This pneumonic device may help you: King KiloHenry Hecto Died Deka Unexpectedly Basic Unit drinking deci chocolate centi milk milli There are more, but these are the ones that concern us.
Steps to convert one metric unit to another: • Count from unit to unit, noting direction of motion. • Use same number and direction to move the decimal point.
Example: Convert 3.14 mm to cm K H D u d c mFind m for milli; find c for centi; note that you need to move one space to the left.Move decimal point one space to the left.3.14 mm = 0.314 cm
More Examples • Convert 50.6 L to mL. 2. How many Kg are the same as 368 g? 3. Convert 0.34 cm to m. 4. Convert 2 km to mm. K H D u d c m
“When are we ever going to need this?” • Sometimes we measure in cm but calculate in meters. • Sometimes we measure in grams but need Kg to use in a formula. • We will use this skill all year!