Measurement
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Transcript of Measurement
Examples of Exact Numbers• exactly 17 students in this class
• exactly 12 eggs in a dozen
• exactly 1000 g in a kilogram
• exactly 2.54 cm in an inch
• The number 1 in any conversion factor between units, as in 1 m = 100 cm is an exact number
Examples of Inexact
Numbers• Height• Weight• Length• Width
Any number obtained by measurement is always inexact.
Significant FiguresWhen making
measurements, it is the size of the
measurement needed to be precise.
Sig. Fig. Rule
1)Non-zero numbers are always significant
2)Zeros between non-zero numbers are always significant.
3)All final zeros to the right of the decimal place are significant.
Sig. Fig. Rule4)Zeros that act as placeholders
are not significant.5)All numbers in calculations
should have same sig. fig. go with the smallest sig. fig. number
6)Counting numbers and defined constants do not change.
What’s the Sig. Fig.• 857
• 950
• 1800
• 45.2
• 45.0
• 92000.0
• 3
• 2
• 2
• 3
• 3
• 6
• 0.00243
• 505
• 0.0012300
• 3.22X105
• 1200.0060
• 0023
• 3
• 3
• 5
• 3
• 8
• 2
Scientific NotationExpresses numbers as a multiple of two factors-a
number between 1 and 10, and 10 raised to a power or exponent; makes it easier to write a really big number or
really small number.
Round to 3 sig. fig.• 15624• 17853• 19278• 17750• 17650• 24503• 276453
• 15600• 17900• 19300• 17800• 17600• 24500• 276000
Rounding Rules• If digit after sig # is above 5, then
round up• If digit after sig # is below 5 then
leave as is• If digit after sig # is 5 and # after
5 is not zero, then round up• If digit after sig # is 5 and # after
5 is zero; if sig # is odd round up and if even then leave as is.
• 1018 exa E
• 1015 peta P
• 1012 tera T
• 109 giga G
• 106 mega M
• 103 kilo k
• 102 hecto h
• 101 deka da
• 10-1 deci d
• 10-2 centi c
• 10-3 milli m
• 10-6 micro µ• 10-9 nano n
• 10-12 pico p
• 10-15 femto f
• 10-18 atto a
Dimensional AnalysisA problem solving
method that focuses on the units that are
used to describe matter.
System International Units (SI Units)
Units are a name tag that lets you know what measurement
the number is for. The SI Units are the standard units use throughout the world.