A. Number vs. Quantity

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A. Number vs. Quantity

• Quantity - number unit

UNITS MATTER!!
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Metrics Base Units
Measurement Base Unit Abbreviation
Length meter m
Mass gram g
Volume liter L
Temperature Celcius (centigrade) or Kelvin oC or K
These are not SI units, but are base units for
these measurements.
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Base units continued
Amount of Substance mole mol
Time seconds s
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A. SI Prefix Conversions
Prefix
Symbol
Factor
Base Units Gram (g) Liter (L) Meter
(m) seconds(s)
move left
move right
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Metrics

• Why use the metric system?

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Metrics

• Because of the worldwide use of science, an
  international system of measurements was
  developed in 1960.
• This system is referred to as the SI (le Systeme
  International).
• This system utilizes specific SI base units.
• The advantage of the system is that it is a
  decimal system based on multiples of 10.
• The system uses prefixes to indicate the
  multiples of 10. (How many times you move the
  decimal.)

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A. SI Prefix Conversions
0.532
532 m _______ km
NUMBER
UNIT
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A. SI Prefix Conversions

• 1. Find the difference between the exponents of
  the two prefixes.
• 2. Move the decimal that many places.

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(exponent of start)-(exponent of end)

• 33 kg to mg
• Kilo has an exponent of 3 and milli has an
  exponent of -3
• (3) (-3) 6 since it is positive, you move
  it places to the right
• 24 mm to m
• Milli has an exponent of -3 and meter is a base
  unit so it has an exponent of 0
• (-3) (0) -3 since it is negative you move
  3 places to the left

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A. SI Prefix Conversions

• 1) 20 cm ______________ m
• 2) 0.032 L ______________ mL
• 3) 45 ?m ______________ nm
• 4) 805 dm ______________ km

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Temperature Scales

• Fahrenheit Based upon the boiling and melting
  points of alcohol.
• Celsius Based upon the boiling and melting
  points of water.
• 0o C Melting Point
• 100o C Boiling Point

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Compare Temperatures
F C (1.8) 32
C F 32 (.555)
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Absolute Temperature

• Kelvin Based scale upon absolute zero.
• Absolute Zero The coldest temperature possible.
  (Theoretical Point)
• Remember that temperature is based on average KE.
  Therefore, at 0 Kelvin there will be absolutely
  no movement of the atoms/molecules of the
  substance.
• Absolute Zero -273.16 C
• Used the same sized graduations as in the Celsius
  scale.

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Kevin to Celsius Comparisons

• Kelvin degrees are the same graduation as Celsius
• They simply start (0) at different places.
• Celsius at Melting Point, Kelvin at Absolute Zero

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Kelvin/Celsius Conversions

• K C 273
• C K 273

A more precise value would be 273.16, but to
keep it simple, well use the 273 value.