How to calculate absolute uncertainty?

Absolute uncertainty is calculated by subtracting the smallest measurement from the largest measurement and dividing by two.

In more detail, absolute uncertainty is a measure of the potential range of error in a measurement. It is often used in scientific experiments and calculations to give a sense of the reliability of results. The absolute uncertainty is usually expressed as a plus or minus value, indicating that the true value could be either above or below the measured value by that amount.

To calculate absolute uncertainty, you first need to identify the smallest and largest measurements in your data set. For example, if you are measuring the length of a piece of string and your measurements are 10.2 cm, 10.4 cm, and 10.3 cm, the smallest measurement is 10.2 cm and the largest is 10.4 cm.

Next, subtract the smallest measurement from the largest. In this example, you would subtract 10.2 cm from 10.4 cm to get 0.2 cm. This is the range of your measurements.

Finally, divide this range by two to get the absolute uncertainty. In this example, you would divide 0.2 cm by 2 to get an absolute uncertainty of ±0.1 cm. This means that the true length of the string could be up to 0.1 cm longer or shorter than your measurements indicate.

It's important to note that absolute uncertainty is just one way of expressing the uncertainty in a measurement. Relative uncertainty, which is the absolute uncertainty divided by the measured value, gives a sense of the uncertainty as a percentage of the measured value. This can be useful for comparing the uncertainties of different measurements.

IB Physics Tutors Summary: Absolute uncertainty shows the possible error in a measurement, expressed as ± a value. To calculate it, take the largest and smallest measurements, subtract the smaller from the larger, and then halve the result. This figure tells you how much the true value might differ from your measurement, helping understand the precision of your results.