Physics is a field of Science, which is quantitative in nature. The purpose of doing experiments in Physics is mainly to collect and analyze the data. In all measurements, there is always some uncertainty associated with the values. The uncertainty may be because of systematic errors or random errors or both.
The errors in a particular experiment may be due to the observer, or to the instrument used, or to a combination of both. They may also be present by the very nature of the experiment; for example, the heat lost by cooling in a heat experiment causes an error, for example by making a cooling correction, or by repeating the experiment and subtracting to eliminate the heat lost. All students doing experiments MUST record the errors and uncertainties in their measurements whenever errors and uncertainties are present in the experiments. Students must take errors and uncertainties into account when calculating and presenting the final results in their laboratory reports.
1. INTRODUCTION TO UNCERTAINTY AND ERRORS
Often the words uncertainty and error are used interchangeably, but it is worthwhile to be a little more precise about what the two words mean in the context of measurement. When we perform a measurement, we are trying to determine the “true” value of the quantity of interest, but the result we obtain will differ from the “true” value by some amount. This difference between the “true” value and the result of our measurement is the error in the measurement. Repeated measurements will yield similar but not identical results. As a result, we cannot ever know precisely what the “true” value of the quantity is; there is always an uncertainty in our results that is ultimately due to the random errors in the measurements.
