Units of Measure
Measuring Devices:
Graduated
Cylinder
The Metric System
Length:
 1000 millimeters = 1 meter
 100 centimeters = 1 meter
 1000 meters = 1 kilometer
Mass (or weight):
 1000 milligrams = 1 gram
 1000 grams = 1 kilogram
 1000 kilograms = 1 metric ton
Volume:
 1000 milliliters = l liter
 1000 liters = 1 cubic meter
Area:
 10 000 square meters = 1 hectare
 100 hectares = 1 square kilometer
Prefixes:
 micro means 1/1 000 000
 milli means 1/1000
 centi means 1/100
 kilo means 1000
 mega means 1 000 000
Symbols:
 m for meter
 mm for millimeter
 cm for centimeter
 km for kilometer
 g for gram
 mg for milligram
 kg for kilogram
 L for liter
 mL for milliliter
 m^{2} for square meter
 m^{3} for cubic meter
 km^{2} for square kilometer
 t for metric ton
 ha for hectare
Some special relationships:
 1 milliliter = 1 cubic centimeter
 1 milliliter of water has a mass of approximately 1 gram
 1 liter of water has a mass of approximately 1 kilogram
 1 cubic meter of water has a mass of approximately 1 metric ton
Legal/official (exact) definitions of inchpound units as set
by U.S. law:
 1 inch = 25.4 millimeters
 1 pound = 453.592 37 grams
 1 gallon = 3.785 411 784 liters
Note: In Canada the inch and the pound are defined identically,
but 1 Canadian gallon = 4.546 09 liters.
Approximate conversion factors between inchpound units and the
International System of Units (SI):
 Multiply inches by 2.54 to get centimeters (this conversion factor
is exact)
 Multiply feet by 0.305 to get meters
 Multiply miles by 1.6 to get kilometers
 Divide pounds by 2.2 to get kilograms
 Multiply ounces by 28 to get grams
 Multiply fluid ounces by 30 to get milliliters
 Multiply gallons by 3.8 to get liters

One of the principal advantages of the Metric System is its
use of only one unit (standard of size) for each parameter (thing that is being
measured). The metric units are interrelated in such a way that only five
fundamental standards are necessary. These fundamental standards are identified
with an * in the tables below.
MECHANICS
Parameter: 
Metric Unit 
English Units 
time
duration, delay 
second *
s 
second, minute
hour, day 
frequency 
hertz
1/s 
cycle per second 
length
distance, displacement 
meter
1/299 792 458 light sec
m 
inch, foot, yard
rod, chain, furlong, mile 
velocity, speed
rate of change of position 
meter per second
m/s 
foot per second
mile per hour, knot 
acceleration
rate of change of velocity 
meter per second squared
m/s^{2} 
foot per second squared 
mass
quantity of material 
gram *
g 
ounce, pound, ton 
force
push, pull, or weight 
newton
kg m/s^{2} 
poundforce 
impulse
force times time 
newton second
kg m/s 
poundforce second 
momentum
mass times velocity 
kilogram meter per second
kg m/s 
pound foot per second 
work, energy
force times distance 
joule (pronounced "jewel")
= one newton meter
kg m^{2}/s^{2} 
foot poundforce 
power
rate of doing work 
watt
= one joule per second
kg m^{2}/s^{3} 
foot poundforce per second
horsepower 
area
size of a surface 
square meter
m^{2} 
square foot, square yard
acre, square mile 
pressure
force per unit area 
pascal
newton per square meter
kg/m s^{2} 
poundforce per square inch 
volume, capacity 
cubic meter (stere)
m^{3} 
pint, quart, gallon
cubic foot, cubic yard 
density, heaviness 
grams per cubic centimeter
g/cm^{3} 
pounds per cubic foot 
HEAT
Parameter: 
Metric Heat Unit 
English Heat Unit 
heat energy 
joule, calorie, Calorie
1 cal = 4.186 joules
1 Cal = 4186 joules 
British Thermal Unit 
temperature change 
kelvin * 
Fahrenheit degree 
temperature 
degrees kelvin 
degrees Fahrenheit 
LIGHT
Parameter: 
Metric Light Unit 
luminous intensity 
candle * 
luminous flux 
lumen
one candle produces 4 pi lumens 
illumination 
lux
lumen per square meter 
focus 
diopter
reciprocal meters 
astronomical distance 
parsec 
ELECTRICITY & MAGNETISM (There are no English electrical
units)
Parameter: 
Metric Electrical Unit 
electric charge 
coulomb *
96,500 coul = 1 faraday
faraday = 1 mole of electrons 
electromotive force (EMF) 
volt (joule per coulomb) 
capacitance 
farad (coulomb per volt) 
electric current 
ampere (coulomb per second) 
electric energy 
joule (watt second)
(newton meter)
KWH = 3,600,000 joules 
electric power 
watt (joule per second) 
electrical resistance 
ohm
(volt per ampere) 
electrical conductivity 
siemens (coulomb per joule)
(ampere per volt) 
electrical field strength 
volts per meter 
electromagnetic inductance 
henry (pl. henrys) 
magnetic field intensity 
oersted (formerly the gauss) 
magnetic flux 
weber (10^{8} maxwells) 
magnetic flux density 
tesla
weber per square meter 
magnetomotive force 
gilbert 
