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Physics vocabulary · Measurement and Units

Significant figures

Meaning in physics, with examples

nounCore term

In physics, significant figures means: The digits in a number that carry real information about its precision, counted from the first non-zero digit. For example, 0.00450 has three significant figures.

In Turkish: anlamlı rakamlar, anlamlı basamaklar

How it is used

Often shortened to 'sig figs' or 's.f.'. As a rule of thumb, give a final answer to the same number of significant figures as the least precise data. Exam questions say 'give your answer to 3 significant figures'.

Example sentences

  1. Your calculator says 9.81476, but the data only justify three significant figures, so write 9.81.

  2. Round the final answer to two significant figures.

Common collocations

  • to three significant figures
  • round to significant figures
  • number of significant figures
  • sig figs
  • uncertaintyThe range within which the true value of a measurement probably lies, written with a ± sign. It shows how reliable a measurement or result is.
  • scientific notationA way of writing very large or very small numbers as a number between 1 and 10 multiplied by a power of ten, for example 3.0 × 10⁸ instead of 300,000,000.
  • SI unitsThe international system of measurement units used in science, based on seven base units such as the metre, kilogram, second, ampere and kelvin. SI comes from the French 'Système international'.
  • order of magnitudeThe approximate size of a number expressed as the nearest power of ten. Two values that differ by a factor of about ten differ by one order of magnitude.

More terms: Measurement and Units

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