The resolution of a measuring instrument determines the smallest change in value that it can discriminate between (and therefore quantify).
E.g. a 2 digit digital thermometer with a range from 0 to 99oC cannot show and increase in temperature of less than 1oC
The resolution of a measuring instrument introduces uncertainty and limits the precision of the measurement. (In the above example the thermometer
measurements will produce an uncertainty of +/- 0.5 oC)
The precision limit set by an instrument can sometimes be further limited by the measurement technique used. E.g. A stopwatch capable of a resolution
of 0.01 seconds will at best achieve an uncertainty of +/- 0.1 seconds when operated manually.
- In some situations there are no clear and unique reference points to measure between and the uncertainty in the measurement must reflect this.
When repeated measurements are made variability in the measured property or random errors in the measurement technique can produce different
measurement values. The uncertainty must reflect this however statistical techniques can be used to improve (reduce) the uncertainty in the final
- The statistical techniques can also provide a confidence value which indicates the confidence that the true value does actually lie within the
uncertainty interval stated.
When measurements are taken of changing values using electrical or mechanical measuring devices it is important that the mechanism can respond
fast enough to reflect the changing value being measured.
In these situations data logging is usually required which involves recording a succession of values quickly enough so that the measured value
is stable while each individual reading is recorded.