1.7 Accuracy, precision & uncertainty in measurement

- Physics is a science based on observations and experiments.

- Observations of various physical quantities are made during an experiment.

- For example, during the atmospheric study we measure atmospheric pressure, wind velocity, humidity, etc.

- All the measurements may be accurate, meaning that the measured values are the same as the true values.

- Accuracy is how close a measurement is to the actual value of that quantity.

- These measurements may be precise, meaning that multiple measurements give nearly identical values (i.e., reproducible results).

- In actual measurements, an observation may be both accurate and precise or neither accurate nor precise.

- The goal of the observer should be to get accurate as well as precise measurements.

- Possible uncertainties in an observation may arise due to following reasons:

1) Quality of instrument used.

2) Skill of the person doing the experiment.

3) The method used for measurement.

4) External or internal factors affecting the result of the experiment.