Confusing Measurements

French National AssemblyAcademy of Sciences

Metric System Insured worldwide standard

Quadrant Surveyors

JBJ Delambre PFA Mechain

Measuring the Quadrant

Early ResearchersJ.R. Benoit

Excited Cadmium Atoms Wavelength

Defined By Light

Meter Stick 1 meter = 3.28 feet

mm And cm

tera- (T-) 1012 1 trillion

giga- (G-) 109 1 billion

mega- (M-) 106 1 million

kilo- (k-) 103 1 thousand

hecto- (h-) 102 1 hundred

deka- (da-)** 10 1 ten

deci- (d-) 10-1 1 tenth

centi- (c-) 10-2 1 hundredth

milli- (m-) 10-3 1 thousandth

micro- (µ-) 10-6 1 millionth

nano- (n-) 10-9 1 billionth

Prefixes

PrefixesMetric Prefixes can be used with any

base unit.

Metric Prefixes

Teaching Prefixes

Learn the 16 regular prefixes by counting

Change them by jumping the decimal point 3 places

Don’t call this “converting units”

Set calculator display to ENG

Avoid the irregular prefixes (h, da, d, c)

except in cm, cm2, cm3, dm3, hm2, hm3

Advantages of MetricsNo conversions

No fractions

No numbers to memorize

No awkward rows of zeroes

Complete

Coherent

Unambiguous symbols

Only 30 units

The world standard

The meter is the length of the path

travelled by light in a vacuum during a time interval of 1/299 792 458 of a second. (1983)