The balance is a piece of equipment that measures the mass of a specific body, providing accurate data about its weight. Among the many existing models, the analytical balance that has a high power of rigor stands out, since with it great precision can be obtained.
Precision is the number of decimal places used to express what is measured, while accuracy indicates the degree of approximation between the measured value and the actual value to be measured. On the other hand, if we refer to a series of measurements, precision is the degree of grouping or repeatability of the measured values or dispersion of the results, while accuracy represents the degree of approximation between the mean of the measured values and the real value.
What precision and accuracy of a balance?
The terms “precision” and “accuracy” are often used interchangeably, as if they were synonymous. However, the accuracy and precision of a balance are different concepts:
- Accuracy: when we talk about the precision of a balance, we generally refer to the indication precision, also called increment, minimum division or interval, which is the smallest scale that the device has, that is, the number of decimal places. Referring to a single measurement, precision (or indication precision) indicates the number of decimal places used to express what is measured, while referring to a series of measurements, precision (or repetitive precision) indicates the degree of grouping or repeatability of the measured values or dispersion of the results.
Repeatability is defined as the degree of mutual approximation or standard deviation of consecutive measurements of the same magnitude, carried out under the same measurement conditions. These measurement conditions include factors such as the measurement procedure, the observer, the measuring device, the location, or the time interval between individual measurements.
- Accuracy: the accuracy of a measuring device, also called the margin of error or truthfulness, is determined by the error that it may have, that is, the proximity to the accepted reference value, which is often called the true value or value real. Referring to a single measurement, the accuracy indicates the degree of approximation or coincidence between a measured value and the actual value to be measured, so the displayed value must coincide with the certified weight value, while referring to a series of measurements, the accuracy indicates the degree of approximation between the mean of the measured values and the actual value to be measured.
What should you keep in mind about scales?
Balances are laboratory equipment that need periodic maintenance to keep them in the best operating conditions. All this in order to guarantee the conservation of its characteristics:
To guarantee the correct operation of a balance, it is necessary to calibrate it during its first installation. And it should be the first of successive periodic calibrations as determined by the balance manufacturer. Calibration is one of the most important aspects to attend to when carrying out maintenance and this is designed to ensure that the results obtained when weighing are accurate and reliable Calibrations, both in mechanical and electronic scales, are carried out performed using standard weights. These weights have an exact known mass and must always match the measurement.