Transcript Introduction to the Metric System

Introduction to the
Metric System
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SI (Metric) System
of measurement
• Definition: System of measurement invented by
the French in 1790. Also called the
International System of Units (SI system).
• The SI system is the most used system of
measurement on Earth (all countries except
the U.S. use this system)
• Common units:
• Length: meter
• Volume: liter
• Mass: Kilogram
WHY DO WE USE THE
METRIC SYSTEM?
• Almost all other countries are
using the metric system
• Companies are refusing to buy
products from the U.S. if not
labeled in metric units
• Scientists need a universal way
to communicate data (SI Units)
WHAT DOES THE METRIC
SYSTEM MEASURE?
•The gram measures mass
•The liter measures volume
(usually liquids)
•The meter measures length or
distance
Length
• The measured distance of an
object, line or path.
• The standard SI unit for length is
the meter.
– Note: there are 1000 millimeters in a
meter and 100 centimeters in a
meter.
Mass
• Mass measures the amount of
matter in an object (how much
stuff is in an object).
• The standard SI unit for mass is
the kilogram.
• The base unit gram is 1/1000th
of a kilogram.
Volume
• Volume measure the amount
of space something takes up.
• The standard SI unit for volume
if the Liter.
• The Liter is normally used for
calculating the volume of
liquids.
HOW BIG IS A
METER?
Definition:
• 1983: The meter is the length
of the path traveled by light in
vacuum during a time interval
of 1/299 792 458 of a second.
– Note: There are 100 centimeters in a
meter and 1000 millimeters in a
meter.
Interesting previous
definitions of meter:
• 1889: a prototype made of an alloy of
platinum with 10% iridium, at the
temperature of melting ice.
• 1799: A platinum prototype.
• 1795: A brass prototype.
• 1793: The meter was defined as 1/10
000 000 of the distance from an Earth
pole to the equator.
HOW BIG IS A
LITER?
Definition:
• 1964: The word
liter may be
employed as a
special name for
the cubic
decimeter.
Previous definitions
of the Liter
• 1901: The unit of volume, for high
accuracy determinations, is the volume
occupied by a mass of 1 kilogram of
pure water, at its maximum density and
at standard atmospheric pressure: this
volume is called liter.
• 1795: Liter is defined as a special name
for the cubic decimeter.
HOW BIG IS A
GRAM?
• A gram is 1/1000 of a kilogram.
• The kilogram is the standard unit of the metric system.
• Definition of a kilogram:
• A kilogram is equal to the mass of the
international prototype of the kilogram
kept at the Bureau International des
Poids et Mesures.
• 1 kilogram is equal to one cubic decimeter of
pure water.
WHY DO WE USE
METRIC PREFIXES?
• In the metric system, larger and
smaller units are constructed by
adding prefixes to the appropriate
base unit.
• The prefixes indicate what power
of ten the base unit was multiplied
by to form the given unit.
Metric Prefixes
• Kilo
• Hecto
• Deka
• unit
• deci
• centi
• milli
• 1, 000
• 100
• 10
•1
• 0.1
• 0.01
• 0.001
• King
• Henry
• Died
•a
• death
• called
• measles
• Stair Step Conversion Method:
Meter
• Kilometer
• Hectometer
• Dekameter
• meter
• decimeter
• centimeter
• millimeter
Gram
• Kilogram
• Hectogram
• Dekagram
• gram
• decigram
• centigram
• milligram
Liter
• Kiloliter
• Hectoliter
• Dekaliter
• liter
• deciliter
• centiliter
• milliliter
kilo-
hecto-
deka-
Base
deci-
centi-
milli-
(dm)
(cm)
(mm)
(cL)
(mL)
(dg)
(cg)
(mg)
0.1
0.01
0.001
unit
(km)
(hm)
(dam) or Meter
(Dm)
(kL)
(hL)
(m)
(daL) or Liter (L) (dL)
(DL)
(kg)
1000
(hg)
100
(dag) or
Gram
(Dg)
(g)
10
1
Be aware the are many
more prefixes for the SI
system