Measured Numbers and Significant Figures

Measurement is about accuracy (correction) and precision (reproduceabilty).

Rules of Significant Figures

1. 1-9 Significant - always

2. Trapped zeros in between values 1-9 are significant

3. Preceeding zeros - Never significant (0.0321)

4. Following zeros - sometimes

   1. If there is a decimal in the number they are significant

   2. If there are no decimals in the number they are not significant (0.00030500) - 5 sigfigs (5120) - 3 sigfigs

SIgnifcant Figures, Multiplication and divisions measured numbers\

cm x cm= cm²

• Round Answer to same sigfigs as # used with least # sigfigs 100mm = 1m (Multiplication)

  • 1.23mm(1m/10000mm) Defined = 0.00123mm 1.23×10^-3

  • 12 m + 1.234m = 13.235

• Round answer to least number decimal places found in # used to calculate (Addition)