AQA GCSE Physics · 8463
Specification 4.5.6.3.2 · Paper 2
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GCSE Physics · key term
The closeness of repeated measurements to one another.
Used by AQA, Edexcel and OCR
Specification 4.5.6.3.2 · Paper 2
Specification 1.4 · Paper 1, Paper 2
The closeness with which a value is stated, often indicated by its number of significant figures or decimal places.
Revise: Significant Figures and Standard FormMeasurements and calculated results should not usually imply more precision than the data justify. If a length is measured as 2.4 m, reporting a result calculated from it as 7.384615 m would suggest an unrealistic level of precision. Significant figures provide a consistent way to state the meaningful precision of a value.
Paper 1, Paper 2
How close repeated measurements are to one another.
Revise: Apparatus Selection, Accuracy and Risk AssessmentAn instrument with finer resolution can help distinguish smaller differences, but precision is judged from the spread of repeated results. Repeating measurements shows how much they vary and can provide a more dependable estimate, but repetition does not correct a faulty zero or poor calibration. Several tightly grouped readings can be precise while all being displaced from the true value and therefore inaccurate.
Closeness of repeated measurements to one another; precise data have little spread.
Include trailing zeros when they are needed to show the stated precision: for example, 0.050 has two significant figures.
Do not use “accurate” and “precise” as synonyms. Accuracy concerns closeness to the true or accepted value; precision concerns how closely repeated results agree.
Do not use “accurate” when you mean that repeated readings are close together. Close repeated readings show precision; accuracy concerns closeness to the true or accepted value.
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