Uncertainty

What is meant by uncertainty?

• The interval within which the true value

  of a quantity can be expected to lie.

• For a measuring instrument, the smallest change

  in a quantity that gives a change in the reading that can be seen.

• A measurement result which is judged

  to be close to the true value.

• Measurements which there is very little spread about the mean value.

What is the resolution of the temperature sensor?

• 1 × 10⁻¹ °C

• 1 × 10⁻² °C

• 1 × 10⁻³ °C

• 1 × 10⁻⁴ °C

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

For a set of repeat measurements,

the uncertainty is ± half the range.

TRUE or FALSE

• TRUE

• FALSE

The student determined

the density of a material three times.

Determine the uncertainty in the student’s results.

• 80 kg/m³

• 160 kg/m³

• 10 kg/m³

• 20 kg/m³

What is the mean and best estimate of the uncertainty for this set of readings: 61.0 s, 63.0 s, 62.0 s, 62.5 s, 61.5 s?

• 61.0 ± 0.1 s

• 62.0 ± 0.2 s

• 62.0 s ± 1.0 s

What is the temperature and uncertainty indicated by this thermometer?

• 24 ± 0.5 °C

• 24 ± 1 °C

• 25 ± 0.5 °C

• 25 ± 1 °C

A stopwatch has a resolution of 0.01 seconds.

What is the best estimate of uncertainty of its readings?

• ± 0.01 s

• ± 0.05 s

• ± 0.1 s

• ± 0.005 s

What is the uncertainty of this graduated cylinder?

• ±0.1ml

• ±0.25 ml

• ±0.5 ml

• ±0.1 ml

What is the uncertainty as a percentage of the reading on this device (percent uncertainty)

• -0.04%

• 100%

• 0.90%

• 0.08%

Which shows an accurate but not precise aim?

• Exp I

• Exp II

• Exp III

• Exp IV