1
Chapter 2  Measurements and Calculations
±
Quantitative
property – measurements in numbers
±
comparison based on a
known/accepted
scale
Example:
Each finger nail of the Guinness world record holder is
about
3
ft
.
±
Always has
2
parts – the
number
and the
unit
The
reliability
of measurement
has to be known

sensitivity,

calibration
of the instrument
The temperature outside is
92
does not
make sense unless
a unit
is specified.
Scale
Scientific Notation
(
Exponential notation)

for assessing
the
magnitude

very
large
or
very small
numbers
in a form of shorthand

expressed
as a
product
number between
1 and 10
and
a
power of 10.
the age of the earth
: 4,600,000,000
years
Æ
4.6
x 10
9
yrs
or
4.6
EE
9
4.6
x 10
^
9
A number,
n
can be written in scientific notation as follows :
n
=
C
x 10
e
exponent
(
positive
or
negative
integer)
coefficient
(always between
1
and
10)
width of a plant cell is around :
0.000013
m
1.3
x 10
5
m
Writing numbers in scientific notation
1.
Check to see if the number is
greater
than
10
or
smaller
than
1
.
If
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 Fall '08
 staff

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