Lab one metric conversions

Lab One: Metric Conversions

Metric System

The metric system is a decimalized system of measurement.

Metric System

Since the 1960s the International System of Units ("Système International d'Unités" in French, hence "SI") has been the internationally recognized standard metric system.

Metric units are widely used around the world for personal, commercial and scientific purposes.

Metric System

A standard set of prefixes in multiples of ten may be used to derive larger and smaller units.

Metric System

The Metric and Customary Systems of Measurement

In today’s global environment, metric measurements are prominent in workplaces, consumer products, and news reports.

Almost every other country in the world uses the metric system of measurement.

Three nations have not officially adopted the International System of Units as their primary or sole system of measurement: Burma, Liberia, and the United States.

The European Union, Japan, and Korea have passed legislation limiting international commerce to products measured in metric units.

Countries by Date of Metrication

If the United States is to continue to play a leading role in international business, using metric measurement is imperative and U.S. workers at all levels must be knowledgeable about the Système Internationale (SI), the international name for the metric system.

The Metric and Customary Systems of Measurement

Cargo errors - The confusion between pounds (mass) and kilograms sometimes means that aircrafts are overloaded. "the shipper's weights had been in kilograms, not pounds, and that, as a result, the aircraft was more than 30,000 pounds overweight".

Importance of Conversion…

Importance of Conversion…

Gimli Glider — In 1983 a Boeing 767 jet ran out of fuel in mid-flight because of two mistakes in figuring the fuel supply of Air Canada's first aircraft to use metric measurements.

Medical errors - Medical errors in the US are sometimes attributed to the confusion between grains and grams. A patient received phenobarbital 0.5 grams instead of 0.5 grains (0.03 grams) after the prescriber misread the prescription.

Importance of Conversion…

Mars Climate Orbiter — In 1999 NASA lost a $125 million Mars orbiter because one engineering team used metric units while another used US customary units for a calculation.

Importance of Conversion…

Metric System

• One of the goals of the metric system is to have a single unit for any physical quantity.

• Another important one is not needing conversion factors when making calculations with physical quantities.

Metric System

• All lengths and distances are measured in meters, or thousandths of a meter (millimeters), or thousands of meters (kilometers), and so on.

Metric System

• There are not different units with different conversion factors, such as inches, feet, yards, fathoms, rods, chains, furlongs, miles, nautical miles, leagues, etc.

Metric System

• Multiples and submultiples are related to the fundamental unit by factors of powers of ten, so that one can convert by simply moving the decimal place: 1.234 meters is 1234 millimeters, 0.001234 kilometers, etc. • The use of fractions, such as 2⁄7 of a meter,

is not prohibited, but uncommon, as it is generally not necessary.

Metric System

• The US uses the English System of measurement.• Not even the

English use the English system anymore.

Metric System

Metric System

• The rest of the world, especially scientists, use the metric system, or System International (SI).

• Since we are in the US, your lab manual uses both systems.• We need to be familiar and comfortable

using both systems.• We also need to be able to convert units

from one system to another.

1. Approximations: the kind you can do easily in your head

2. Precise Equivalents: necessary for exact measurements.

Levels of ConversionThere are two levels of conversion:

Commonly used conversions: pages 3-4

Rounding

• Often numbers are not exact• Is 3.2571429 correct or useful number?

Rounding

• No… • It is usually implied that the greater

number of digits more precise.• Not always

• Distance measurement is only accurate to tenths of centimeters, so a final answer should be no than one decimal point.

Rounding

Rounding

• If the first digit to be dropped is less than 5, leave the preceding digit.

• If the digit is greater than 5, increase the preceding digit by one.• Example: 6.74 = 6.7• Example: 6.75 = 6.8

Problems

• Beginning on page 5• Use the conversion charts on pages 3

and 4• Do problems part one # 1 A-G, #2 A-

I, and part two #1 A-G, #2 A-I

Part One # 1 Problems

• A centimeters to inches• 10 cm =______ inches• 1 cm = 0.394 in• 10 cm X 0.394 in = 3.94 in

• Rounded = 3.9 in• B meters to feet

• 10 m = ______ ft• 1 m = 3.281 ft• 10 X 3.281 = 32.81 ft

• Rounded 32.8 ft• C kilometers to miles

• 50 km = _____ mi• 1 km = 0.621 mi• 50 km X 0.621 mi = 31.05 mi…..31 mi

Part One # 1 Problems

• D liters to quarts• 60 lt = ________ qts• 1 lt = 1.057 qts• 60 X 1.057 = 63.42….63.4 qts

• E grams to ounces• 98 g = _______oz• 1 g = 0.035 oz• 98 X 0.035 = 3.43…….3.4 oz

• F kilograms to pounds• 20 kg _____ lbs• 1 kg = 2.205 lbs• 20 X 2.205 = 44.1 lbs

• G Celsius to Fahrenheit

Part One # 1 Problems

• G Celsius to Fahrenheit• This is a little different, there is a

formula to convert: (C° X 1.8) + 32 = F°• 39° C = ______ °F

• (39 X 1.8) + 32 = 33.8° F

• 100° C = _____ °F• (100 X 1.8) + 32 = 212° F

• 1° C = ______ F °• (1 X 1.8) + 32 = 33.8° F

Part One Problems #2

• A inches to centimeters• 8 in = _____ cm• 1 in = 2.54 cm• 8 X 2.54 = 20.32 cm…rounded 20.3 cm

• B feet to meters• 6 ft = ____ m• 1 ft = 0.305 m• 6 X 0.305 m = 1.83 m…..1.8 m

• C yards to meters• 12 yds = ______ m• 1 yd = 0.914 m• 12 X 0.914 = 10.94 m …… 11 m

Part One Problems #2

• D miles to kilometers• 20 mi = ___ km• 1 mi = 1.609 km• 20 X 1.609 = 32.18….32.2 km

• E quarts to liters• 12 qts = ____ lt• 1 qt = .946 lt• 12 X .946 = 11.352….11.4 lt

• F gallons to liters• 5 gal = _____ lt• 1 gal = 3.785 lt• 5 X 3.785 = 18.9…19 lt

Part One Problems #2

• G ounces to grams• 6 oz = _____ g• 1 oz = 28.35 g• 6 X 28.35 = 170.1 g

• H pounds to kilograms• 20 lbs = ____ kg• 1 lb = 0.454 kg• 20 X 0.454 = 9.08….9.1 kg

Part One Problems #2

• I Fahrenheit to Celsius• Another formula: (F° - 32) / 1.8 = C°• 90° F = ____° C

• (90 – 32) / 1.8 = 56.2° C

• 15° F = ____° C• (15-32) / 1.8 = -9.4° C

• 212° F = _____° C• (212-32) / 1.8 = 100°C