Measurements and

Significant Figures

Many Observation are Measurements What is a Measurement? Quantitative observation. Comparison to an agreed upon standard. Every measurement has a number and a

unit.

Measurements: Precision can be Communicated by Significant Figures

Accurate, but not very precise

Accurate and precise

Precise, but not very accurate

Significant Figures Writing Numbers to Reflect Precision Any non-zero number is significant. What about zeros?

0.0165 85.950 12.061

Zeros before non-zero numbers are not significant. (3 sf)

Zeros after non-zero numbers to the right of the decimal point are significant. (5 sf)

Zeros between non-zero numbers are significant. (5 sf)

Significant Figures 10 Cannot tell!! Use scientific notation.

1 sf or 2 sf??? 10 = 1.0 x 101 OR 1 x 101

10. use decimal point to show sf. 2 sf (I think its best to use scientific notation!)

2 sig figs 1 sig fig

Significant Figures in Calculations Addition/Subtraction: The number of decimal places is equal to the least number of

decimal places going in.

Significant Figures in Calculations Multiplication/Division: The number of sig figs is equal to the least number of sig figs going in.