Using Scientific Measurements

SI Units and Dimensional Analysis

SI Units

• Universal standard of measurementsQuantity Quantity Symbol Unit Name Unit Abbreviation

Length l Meter m

Mass m Kilogram kg

Time t Second s

Temperature T Kelvin K

Amount of substance n Mole mol

Electric Current I Ampre A

Luminous Intensity Iv candela cd

SI Units- Prefixes

• Used to indicate values larger of smaller than the SI unit

Prefix Unit Abbreviation

Exponential Factor

Tera T 1012

Giga G 109

Mega M 106

Kilo k 103

Hecto h 102

Deka da 101

100

deci d 10-1

centi c 10-2

milli m 10-3

micro µ 10-6

nano n 10-9

pico p 10-12

Dimensional Analysis

• Method of solving problems using conversion factors

• Conversion factor- ratio derived from the equality between two different units that can be used to convert from one unit to the other

Solving Problems Using Dimensional Analysis

• quantity sought= quantity given × conversion factor• Multiply all top numbers together

– Divide by all bottom numbersEx. How many quarter are in four dollars?

4 dollars x 4 quarters = 16 quarters1 dollar

Practice

How many seconds are in a day?

How many milliliters are in five liters?