Errors are an inherent part of the scientific process. Every measurement has an associated error, no matter how small. Because the measurement of physical quantities are central to science, scientists need to care about errors.
Types of errors
There are three ($3$) types of errors:
- Systematic errors - consistent errors which occur due to the system being used to conduct the experiment. This system consists of the environment (e.g. temperature not being intentionally controlled), observation (e.g. parallax errors and flawed apparatus setup) and instruments (e.g. a metre rule can only distinguish as small as a millimeter)
- Random errors - happen in an unpredictable manner due to factors outside of the scope of the scientific experiment e.g. wind, temperature variations, voltage fluctuations
- Gross errors - these happen due to mistakes and oversights on the part of the experimenter (the person conducting the scientific experiment) e.g. writing down the wrong measurements or misreading a scale
Propagation of errors
When we add or subtract two values, we need to add their absolute errors.
When we multiply or divide two values, we need to add their relative errors.
Research Questions
- What is a systematic error?
- What is a random error?
- What is meant by the term ‘precision’?
- What is meant by the term ‘accuracy’?
- What is the uncertainty/error of a derived quantity given the absolute or relative uncertainties of the other physical quantity of which it is comprised?
- When we add or subtract multiple measurements, do we add their absolute uncertainties or their relative uncertainties?
- When we multiply or divide multiple measurements, do we add their absolute uncertainties or their relative uncertainties?