Measurement uncertainty and experimental evaluation: basic principles
How it works
Measurement uncertainty describes how accurately a measurement result can be estimated. Every measurement has an uncertainty because measuring instruments are only limitedly precise and external influences can have an effect. The uncertainty is often given as a ± value. For several measurements of the same quantity, one can determine the mean value and consider the spread of the values. In experimental evaluation, one distinguishes between random errors and systematic errors, compares measurement results sensibly and rounds appropriately to the uncertainty.
No measurement is completely exact. Results are given with an appropriate uncertainty, for example as measured value ± uncertainty. Repeated measurements help above all to assess random fluctuations; systematic errors do not disappear automatically as a result. Mean value, spread and sensible rounding belong to the evaluation.
An example
A ruler has a smallest division of 1 mm. In class, the reading uncertainty is assumed to be half the smallest division. You measure a length and read 12.30 cm. How do you state the result with uncertainty?
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50 Exercises
To the learning unit →Own explanation and own practice exercises by AmyMath. Subject reference framework: Physics. The topic assignment may vary by federal state.