DATA

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DATA
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the search for relationships to explain and
predict the behavior of the universe
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the science that deals with the
relationship between matter and energy
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There is no such thing as absolute certainty of a
scientific claim.

• The validity of a scientific conclusion is always
  limited by
• the experiment
• design, equipment, etc...
• the experimenter
• human error, interpretation, etc...
• our limited knowledge
• ignorance, future discoveries, etc...

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Scientific Law
a statement describing a natural event
Scientific Theory
an experimentally confirmed explanation for a
natural event
Scientific Hypothesis
an educated guess (experimentally untested)
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developed in France in 1795 a.k.a. SI -
International System of Units

• The U.S. was (and still is) reluctant to go
  metric.
• very costly to change
• perception of Communist system
• natural resistance to change
• American pride

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• The SI unit of
• length is the meter, m
• time is the second, s
• mass is the kilogram, kg.
• electric charge is the Coulomb, C
• temperature is the degree Kelvin, K
• an amount of a substance is the mole, mol
• luminous intensity is the candle, cd

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• The second is defined in terms of
• atomic vibrations of Cesium-133 atoms.
• The meter is defined in terms of the speed of
  light.
• The kilogram is still defined by
• an official physical standard.

Derived units are combinations of these
fundamental units
Examples include speed in m/s, area in m2, force
in kg.m/s2, acceleration in m/s2, volume in m3,
energy in kg.m2/s2
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1018 exa E 1015 peta P 1012
tera T 109 giga G 106 mega M
103 kilo k 102 hecto h 101
deka da
10-18 atto a 10-15 femto f 10-12
pico p 10-9 nano n 10-6
micro m 10-3 milli m 10-2 centi
c 10-1 deci d
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Explore the metric system at link1, link2, link3,
and link4. See definitions of metric units
here. Click here to do conversions.
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All measurements have some degree of uncertainty.
Precision single measurement - exactness,
definiteness group of measurements - agreement,
closeness together
Accuracy closeness to the accepted value
accepted - observed accepted
error
x 100
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1. All non-zero digits are significant. 2. Final
zeros after significant digits are
significant. 3. Zeros between other significant
digits are significant. 4. Leading zeros and
final zeros before the decimal are not
significant.
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Operations with Significant Digits
Addition and Subtraction
round the sum or difference to the least precise
decimal place
Multiplication and Division
round so that the product or quotient has a total
number of significant digits equal to the total
number of significant digits of the least precise
quantity
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Learn more about significant digits here and
here. Check your understanding here and here.