The Metric System from Industry Week 1981 November

The Metric System from Industry Week, 1981 November 30

Metric System Basics

The Metric System • Used in nearly every country in the world, the Metric System was devised by French scientists in the late 18 th century. The goal of this effort was to produce a system that used the decimal system rather than fractions as well as a single unified system that could be used throughout the entire world. tem Internationale S. I. = Sys

Metric System • The metric system is based on a base unit that corresponds to a certain kind of measurement • Length = meter • Volume = liter • Mass = gram • Prefixes plus base units make up the metric system – Example: • Centi + meter = Centimeter • Kilo + liter = Kiloliter

Quantity Definitions: • Length = the distance between two points; the longest dimension of an object • Volume = the amount of space taken up by something • Mass = the amount of matter an object has

Metric System • So if you needed to measure length you would choose meter as your base unit – Length of a tree branch • 1. 5 meters – Length of a room • 5 meters – Length of a ball of twine stretched out • 25 meters

Quantity measured mm 10 mm = 1 cm centimeter cm 100 cm = 1 m meter m kilometer km 1 km = milligram Volume Symbol millimeter Length, width, distance, thickness, girth, etc. Unit Relationship mg 1000 mg = gram g kilogram kg metric ton t 1 t = second s degree Celsius °C square meter m² hectare ha square kilometer km² 1 km² = milliliter m. L 1000 m. L = cubic centimeter cm³ 1 cm³ = 1 m. L liter L 1000 L = 1 m³ cubic meter m³ 1 kg = 1 ha = 1000 m 1 g 1000 g 1000 kg 10 000 m² 100 ha 1 L

Quantity measured Unit Symbol Relationship meter per second m/s kilometer per hour km/h Density kilogram per cubic meter kg/m³ Force newton N Pressure, stress kilopascal k. Pa Electric current watt W kilowatt k. W kilojoule k. J megajoule MJ kilowatt hour k. W·h ampere A Speed, velocity 1 km/h = 1 k. W = 1 MJ = 1 k. W·h = 0. 278 m/s 1000 W 1000 k. J 3. 6 MJ

Metric Staircase kilo 1000 hecto 100 deca 10 meter, m liter, L gram, g Key units 1 deci 0. 1 cent 0. 01 milli 0. 001

Converting with the Metric System • King Henry Drinks Milk During Castle Meetings • Kilo- Hecto- Deca- Meter Deci- Centi- Milli • 1000 10 1 0. 1 . 001 • 1000 m = ______ km • . 001 hg = ______ dg • 42. 7 L = _____ c. L

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 meter liter gram deci centi milli

Metric System • The three prefixes that we will use the most are: – kilo – centi – milli kilo hecto deca Base Units meter gram liter deci centi milli

Prefixes T tera 1012 1 000 000 trillion G giga 109 1 000 000 billion M mega 106 1 000 million k kilo 103 1 000 h hecto* 102 100 da deka* 101 10 ten 100 1 one thousand hundred d deci* 10 1 0. 1 tenth c centi* 10 2 0. 01 hundredth m milli 10 3 0. 001 thousandth µ micro 10 6 0. 000 001 millionth n nano 10 9 0. 000 001 billionth p pico 10 12 0. 000 000 001 trillionth

Metric System – Centimeters are 10 times larger than millimeters so it takes more millimeters for the same length 1 centimeter = 10 millimeters Example not to scale 40 1 mm 41 1 mm 1 mm 40 1 mm 41 1 cm

Metric System • But what if you need to measure a longer distance, like from your house to school? – Let’s say you live approximately 10 miles from school • 10 miles = 16093 meters – 16093 is a big number, but what if you could add a prefix onto the base unit to make it easier to manage: • 16093 meters = 16. 093 kilometers (or 16. 1 if rounded to 1 decimal place)

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

Metric Staircase kilo 1000 hecto 100 deca 10 Key units 1 deci 0. 1 cent 0. 01 milli 0. 001

Converting with the Metric System • When converting within the metric system it is simply a measure of moving the decimal in the appropriate direction.

Metric System • For each “step” to right, you are multiplying by 10 • For example, let’s go from a base unit to centi 1 liter = 10 deciliters = 100 centiliters ( 1 x 10 = 10) = (10 x 10 = 100) 2 grams = 20 decigrams = 200 centigrams (2 x 10 = 20) kilo hecto deca meter liter gram = (20 x 10 = 200) deci centi milli

Metric System • An easy way to move within the metric system is by moving the decimal point one place for each “step” desired Example: change meters to centimeters 1 meter = 10 decimeters = 100 centimeters or 1. 00 meter = 10. 0 decimeters = 100. centimeters kilo hecto deca meter liter gram deci centi milli

Metric System • Now let’s try our previous example from meters to kilometers: 16093 meters = 1609. 3 decameters = 160. 93 hectometers = 16. 093 kilometers • So for every “step” from the base unit to kilo, we moved the decimal 1 place to the left (the same direction as in the diagram below) kilo hecto deca meter liter gram deci centi milli

Metric System • If you move to the left in the diagram, move the decimal to the left • If you move to the right in the diagram, move the decimal to the right kilo hecto deca meter liter gram deci centi milli

Metric System • Now let’s start from centimeters and convert to kilometers 400000 centimeters = 4. 00000 kilometers kilo hecto deca meter liter gram deci centi milli

Metric System • Now let’s start from meters and convert to kilometers 4000 meters = 4 kilometers kilo hecto deca meter liter gram deci centi milli • Now let’s start from centimeters and convert to meters 4000 centimeters = 40 meters kilo hecto deca meter liter gram deci centi milli

Metric System • Now let’s start from meters and convert to centimeters 5 meters = 500 centimeters kilo hecto deca meter liter gram deci centi milli • Now let’s start from kilometers and convert to meters. 3 kilometers = 300 meters kilo hecto deca meter liter gram deci centi milli

Metric System • Now let’s start from kilometers and convert to millimeters 4 kilometers = 4000000 millimeters or 4 kilometers = 40 hectometers = 400 decameters = 40000 decimeters = 400000 centimeters = 4000000 millimeters kilo hecto deca meter liter gram deci centi milli