Recall from the rules given earlier that
tailing zeros appearing at the
RIGHT of the decimal point in reported numbers
are significantExample: 0.00120
is a measurement with three significant figures
What about very large numbers where tailing zeros that appear to the left of the decimal point? The examples below show that
trailling zeros that appear to the
LEFT of the decimal point
are not necessarily significant.
Example: A reported measurement of 350 g may have either two or three signficant figures.
Example: A reported measurement of 57 400 kg may have 3, 4 or 5 significant figures
The potential ambiguity may be avoided by using scientific notation.
Example: A measurement reported as 3.5 × 102 g clearly has two significant figures.
Example: A measurement reported as 3.50 × 102 g clearly has three significant figures.
Indeed, even for the small numbers, use of scientific notation is a useful way to be sure of significant figures.
Example: 0.00120
= 1.20 × 10
–3 The unit of this measurement can be converted to
by multiplying by 10
3.
1.20 × 10
–3 = 1.20
.
This conversion does NOT change the number of significant figures.