Transcript Early Measurement History

Early Measurement History
to
Metric System
What Do the Following Terms Mean?
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The Cubit . . .
The Fathom . . .
The Hand/span . . .
The Pace . . .
The Foot . . .
The Girth . . .
The Palm . . .
The Cubit
The cubit was the
measurement used
by the Egyptians to
build the pyramids.
The cubit is the
measure from your
elbow to the tip of
your middle finger
when your arm is
extended.
The Fathom
The fathom was used
by seamen to
measure the depth of
water so that boats
would not run
aground and be
stranded.
The fathom is the
measure from
fingertip to fingertip
when your arms are
stretched sideways as
far as they will go.
You sometimes see a
rope or fabric
measured in this way.
The Hand-span
The hand-span was
used to measure the
height of horses.
People still describe
horses as being so
many hands high.
The hand-span is the
measure from the tip
of your pinky to the tip
of your thumb when
your hand is stretched
out.
The Pace
This term was used
by the Roman army to
judge speed. The
term is still used
frequently during
various types of foot
races.
The pace is the
measure of distance
from one step to
another.
The Foot
A measurement equal
to the length of an
individuals foot.
King Henry 1
standardized this
measurement,
because his foot was
12 inches long.
The Girth
Girth was a
measurement often
used to measure
fishing line.
The girth was the
measurement around
one’s stomach (your
belt measure).
The Palm
The palm is the
width of your four
fingers when they
are placed
together.
Some folks found
measuring in this fashion to
be quite challenging.
Enter…The Metric System
By the eighteenth century, dozens of
different units of measurement were
commonly used throughout the world.
The lack of common standards led to a lot
of confusion in trade between countries.
At the end of the century, the French
government sought to solve this problem.
Enter…The Metric System
In 1790, the French National Assembly
commissioned the Academy of Science to
design a simple decimal-based system of
units.
The system they devised is known as the
metric system.
In 1960, the metric system was officially named
the Système International d'Unités (or SI for
short) and is now used in nearly every country
in the world except the United States.
Enter…The Metric System
The metre was originally calculated
as one ten-millionth of the distance
from the North Pole to the Equator
through Paris, but it is now defined in
terms of wave length.
STOP
But…you say, we don’t use the metric
system here in the US?
Our distances are measured in miles,
our paper in inches, our milk in
gallons?
Why? And is this right?
Now…
we stop and debate!
Post Debate
• Okay…so since we have several systems
of measurement in place
• We need to learn when to use which
measurement
• And
• How to convert between all of them!
Why it is so important?
CNN News Headline
NASA: Human error caused loss of Mars orbiter
November 10, 1999
• WASHINGTON (AP) -- Failure to convert English measures to
metric values caused the loss of the Mars Climate Orbiter, a
spacecraft that smashed into the planet instead of reaching a safe
orbit, a NASA investigation concluded Wednesday.
• The Mars Climate Orbiter, a key craft in the space agency's
exploration of the red planet, vanished after a rocket firing
September 23 that was supposed to put the spacecraft on orbit
around Mars.
The Seven Fundamental SI Units
(le Système International, SI)
Physical Quantity
Name
Abbreviation
kilogram
kg
Length
meter
m
Time
second
s
Temperature
Kelvin
K
Ampere
A
mole
mol
candela
Cd
Mass
Electric Current
Amount of Substance
Luminous Intensity
SI Prefixes
Common to Chemistry
Prefix
Kilo
Deci
Centi
Milli
Micro
Unit Abbr.
k
d
c
m

Exponent
103
10-1
10-2
10-3
10-6
Metric to English
Distance
1 inch = 2.54 cm
1 foot = 0.3 meters
1 yard = 0.9 meters
1 mile = 1.6 kilometers
Weight
1 ounce = 28.4 grams
1 pound = 0.5 kilograms
1 pound = 500 grams
Volume
1 teaspoon = 4.9 milliliters
1 cup = 237 milliliters
1 pint = 473 milliliters
1 quart = 0.9 liters
1 gallon = 3.79 liters
Conversions in the metric system are merely a
matter of moving a decimal point. The “base unit”
means the you have a quantity (grams, meters,
Liters, etc without a prefix.
Metric Conversions
g
m
L
1000
kilo
100
hecto
10
deka
Base
unit
1
0.1
.01
deci
centi
2
18 L
18 liters = 18 000 milliliters
Example #1: Convert 18 liters to milliliters
.001
milli
3
Metric Conversions
g
m
L
103
102
101
kilo
hecto
deka
10-1
Base
unit
10-2
deci
3
450 mg = 0.450 g
Example #2: Convert 450 milligrams to grams
10-3
centi
2
milli
1
450 mg
Metric Conversions
g
m
L
103
kilo
102
101
hecto
deka
1
2
10-1
Base
unit
3
10-2
deci
4
20 kg
20 kg = 20 000 000 mg
Example #3: Convert 20 kilograms to milligrams
10-3
centi
5
milli
6