Page 19 - Science Course 1 (Book 1)

Mo. 1 - L2a What is the International System of Units(SI)?

SI Base Units

Base Quantity Name Symbol The SI system is based on multiples of ten.
Length meter m Factors of ten are represented by prefixes.
Mass kilogram kg
Time second s You either multiply or divide by a
Electric Current ampere A factor of ten to convert from one SI unit to
Temperature kelvin K another.
Amount of Substance mole mol
Luminous intensity candela cd Prefixes
Prefix Unit (Symbol)
SI Derived Units Mega - (M) 1,000,000(106 )

Derived Quantity Name Symbol Equivalent SI Kilo - (k) 1,000(10³)
100(10²)
Hecto - (h)
Units
Frequency hertz Hz S - 1 Deka - (da) 10(10¹)
–1
Force newton N m kg s - 2 Deci - (d) 0.1(10 )
–2
Pressure pascal Pa N/m 2 Centi - (c) 0.01(10 )
–3
Energy joule J J m Milli - (m) 0.001(10 ) –6
Micro - ( )
0.000 001(10 )
Power watt W J/s
Electric charge coulomb C S A Key Concept
Electric potential volt V W/A What is the International System of Units (SI)?
Electric resistance ohm V/A
Celsius temperature degree Celsius C K* Why did scientists create the International
System of Units?
Unit degree Celsius is equals in magnitude to unit kelvin

SI Prefixes

Factor Name Symbol Numerical Value
10 12 tera T 1 000 000 000 000
10 9 giga G 1 000 000 000
10 6 mega M 1 000 000
10 3 kilo k 1 000
10 2 hecto h 100
10 1 deka da 10
10 -1 deci d 0.1
10 -2 centi c 0.01
10 -3 milli m 0.001
10 -6 micro 0.000 001
10 -9 mano n 0.000 000 001 SUMMARY
10 -12 pico p 0.000 000 000 001 What is the International System of Units (SI)?
Scientists developed one universal system
All SI units are derived from seven base units of units, the international System of Units
(SI), to improve communication among
SI Base Units scientists.

Quantity Measured Unit (Symbol)
Length meter (m)
Mass kilogram (kg)
Time seconds (s)
Electric current ampere (A)
Temperature kelvin (K)
Substance amount mole (mol)
Light intensity candela (cd)

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