Transcript Measurements

Measurements
Mass
Length
Time
Temp.
SI
kilogram (Kg)
meter (m)
second (s)
Kelvin (K)
Common
gram (g)
centimeter (cm)
second (s)
Celsius (0C)
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Kilo = 1000, (k), 103
centi = 100, (c), 102
Micro = 1/1,000,000 = 10-6 (µ)
Nano = 10-9
so
1g = 1,000,000µg = 106g
1cm = 10-2m
1m = 100cm
1 sec = 109ns
Examples of Independent Units
(stand alone)
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Table 1. SI base units
Base quantity
Name
length
meter
mass
kilogram
time
second
electric current
ampere
thermodynamic temperature Kelvin
amount of substance
mole
luminous intensity
candela
Symbol
m
kg
s
A
K
mol
cd
Examples of derived units
(do not stand alone)
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Table 2. Examples of SI derived units
Derived quantity Name
Symbol
area
square meter
m2
volume
cubic meter
m3
speed, velocity
meter per second
m/s
acceleration
meter per second squared m/s2
wave number
reciprocal meter
m-1
continued
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mass density
specific volume
current density
magnetic field strength
amount-of-substance
• luminance
• mass fraction
kilogram per cubic meter
kg/m3
cubic meter per kilogram
m3/kg
ampere per square meter A/m2
ampere per meter
A/m
concentration
mole per cubic meter
mol/m3
candela per square meter cd/m2
kilogram per kilogram,
which may be represented by the
number 1 kg/kg = 1
Independent units you should know
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Mass
Quantity of matter
Constant regardless of position
Occupies space
Measured with a balance –actually comparing
masses
Weight
Effect of gravity on mass
Changes with position
Measured with a scale
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Temperature
Measure of the hotness of an object
Man made
Measured with a thermometer (0C)
Heat is energy that is detected only when it flows from
high to low temp., naturally occurring (always flows
from high to low temp.)
• Boiling = 1000C, Freezing = 00C
• Absolute 0 = lowest temperature that can exist in the
Universe 0C = -273.150C
• Kelvin (K) = absolute 0 =0C = -273.15
Derived Units = dependant that you
should know
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SI
Common
• Volume = l x w x h = m3 cm3
(cubic centimeter, cc)
• Density = mass/volume kg/m3 g/cm3
-chapter 17 in your book
• Example of volume
• 8.42cm x 5.749cm x 3.6cm = 174.26cm3 = 170cm3 =
1.7 x 102cm3 two significant digits
• Example of Density
• A fish tank measuring 14.3cm x 73.0cm x
.72cm is filled with olive oil that has a mass of
8.2 x 103g. What is the density of the olive oil
in g/cm3
________
g/cm3
(if you took a sugar cube 1cm X 1cm x 1cm and melted it, it
would fill a graduated cylinder exactly to 1ml. So a cm3 = 1ml)