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Physics vocabulary · Experiments and Problem Solving

Uncertainty

Meaning in physics, with examples

/ʌnˈsɜːrtənti/nounCore term

In physics, uncertainty means: The range within which the true value of a measurement probably lies, written with a ± sign. It shows how reliable a measurement or result is.

In Turkish: belirsizlik, ölçüm belirsizliği

How it is used

Every lab report needs uncertainties: absolute uncertainty (±0.1 cm), percentage uncertainty (±2%) and the uncertainty in the final result. The uncertainty of a ruler reading is often taken as half the smallest division. You estimate, calculate and reduce uncertainty.

Example sentences

  1. The length is 24.5 ± 0.1 cm, so the percentage uncertainty is about 0.4%.

  2. Repeating the measurement and taking an average reduces the random uncertainty.

Common collocations

  • absolute uncertainty
  • percentage uncertainty
  • measurement uncertainty
  • estimate the uncertainty
  • within the uncertainty
  • systematic errorAn error that shifts every reading in the same direction by a similar amount, for example because of a badly calibrated instrument or a zero error. Repeating the measurement does not remove it.
  • significant figuresThe 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.
  • line of best fitA straight line or smooth curve drawn on a graph so that it passes as close as possible to all the plotted points, showing the overall trend of the data.
  • uncertainty principleA rule of quantum physics stating that certain pairs of quantities, such as a particle's position and momentum, cannot both be known exactly at the same time.

More terms: Experiments and Problem Solving

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