1. Systems of Measurement
Why do we need a standardized system of measurement?
Scientific community is global
An international “language” of measurement allows ALL scientists to communicate

2. Metric System & SI
The first standardized system of measurement: the “Metric” system
Developed in France in 1791
Named based on French word for “measure”
based on the decimal (powers of 10)
Systeme International d'Unites (International System of Units)
Modernized version of the Metric System
Abbreviated by the letters SI.
Established in 1960, at the 11th General Conference on Weights and Measures.
Units, definitions, and symbols were revised and simplified.

3. Components of the SI System
The SI system of measurement has 3 parts:
base units
derived units
prefixes

4. SI: Base Units length meter m mass gram g time second s
Physical Quantity
Unit Name
Symbol
length
meter m
mass
gram g
time
second s
electric current
ampere A
temperature
Kelvin K
amount of substance
mole
mol
luminous intensity
candela cd

5. SI: Derived Units area square meter m2 volume cubic meter m3 speed
Physical Quantity
Unit Name
Symbol
area
square meter m2
volume
cubic meter m3
speed
meter per
second
m/s
acceleration
second squared
m/s2
weight, force
newton N
pressure
pascal Pa
energy, work
joule J

6. Prefixes Prefix Symbol Numerical Multiplier Exponential Multiplier
yotta Y
1,000,000,000,000,000,000,000,000
1024
zetta Z
1,000,000,000,000,000,000,000
1021
exa E
1,000,000,000,000,000,000
1018
peta P
1,000,000,000,000,000
1015
tera T
1,000,000,000,000
1012
giga G
1,000,000,000
109
mega M
1,000,000
106
kilo k
1,000
103
hecto h
100
102
deca da 10
101
no prefix means: 1

7. Prefixes Prefix Symbol Numerical Multiplier Exponential Multiplier
no prefix means: 1
100
deci d
0.1
10¯1
centi c
0.01
10¯2
milli m
0.001
10¯3
micro
10¯6
nano n
10¯9
pico p
10¯12
femto f
10¯15
atto a
10¯18
zepto z
10¯21
yocto y
10¯24

8. “Staircase” Method

9. Problem: convert 114.55 cm to km

10. Dimensional Analysis Factor-Label Method
Multiply by conversion factor (a fraction that relates the original unit and the desired unit)
Conversion factor is always equal to 1.
Numerator and denominator should be equivalent measurements.
When measurement is multiplied by conversion factor, original units should cancel

11. Dimensional Analysis Factor-Label Method
Convert 6.5 km to m

12. Convert 3.5 hours to seconds

13. Units of Volume The space occupied by matter Derived from length (m3)
Non-SI = Liter
1000 cm3 = 1 L mL = 1 cm3
Instruments: graduated cylinder, pipet, buret, volumetric flask

14. Units of Temperature
Temperature – a measure of how hot or cold an object is (the avg. kinetic energy of particles in matter)
Heat flows from higher temp. to lower temp.
Substances expand as temp. increases (exception??)

15. -freezing point of water = -boiling point of water = Kelvin scale
Celsius scale
-freezing point of water =
-boiling point of water =
Kelvin scale
0 K (absolute zero) = °C
K = °C °C = K - 273

17. Units of Energy Joule (J) = SI unit of energy Calorie (cal)
1 J = cal
1 cal = J