On the importance of being a.....

***Sig Fig****

Significant Figures are of critical importance in the LABORATORY.

They have a two fold purpose;
They indicate.........
1. the limiting accuracy of an experimental measurement.
the limit in the  accuracy of a
value calculated from this measurements.

Errors made in the measurement are propagated through the calculations.

In a measurement......

Your ability to duplicate a measurement determines the number of sig figs in the measurement.

Sig Figs vs Random Numbers
The following is a simulated measurement of atmospheric pressure (mm Hg), using a computer interfaced with a pressure sensor. The sampling time is about two seconds and the computer has been arbitrarily set to read out the pressure to five decimal place.
Click on the box below, and observe the readouts. From these observations, determine atmospheric pressure to the correct correct number of sig figs. Then return and check your answer with mine.

Click above to start the data display

RWK 7/24/97