Uncertainties in measurements: chemistry
I can explain why there is some uncertainty when measurements are made, how to minimise uncertainty, and calculate uncertainties.
Uncertainties in measurements: chemistry
I can explain why there is some uncertainty when measurements are made, how to minimise uncertainty, and calculate uncertainties.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Whenever a measurement is made, there is always some uncertainty about the result obtained.
- The uncertainty of an individual measurement is equal to half the resolution of the device used to take the measurement.
- The higher the resolution, the lower the uncertainty of an individual measurement.
- Half the range of repeated measurements equals the uncertainty of a mean value.
- The uncertainty of a measurement provides a range within which the actual value can be found.
Keywords
Uncertainty - is the range of measurements within which the true value can be expected to be found. On apparatus, it is half the value of one resolution marking.
Measurement - provides quantitative information about an object or system.
Mean - is an average calculated by adding up the values of a set of measurements and dividing by the number of measurements in the set.
Resolution - is the smallest change a piece of apparatus can measure - shown by its markings.
Apparatus - a piece of equipment that is designed for a particular use.
Common misconception
Pupils rarely consider the choice of equipment and its link to the accuracy of the data they collect in a practical.
Highlight that equipment with smaller resolution provides more precise measurements, which can decrease the uncertainty of a calculated mean.
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
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Starter quiz
6 Questions
An error that has an equal probability of being too high or too low.
The closeness of two or more measurements to each other.
The degree to which a measurement reflects the true value.
A variable that is kept constant throughout an experiment.
Exit quiz
6 Questions
Quantitative information about an object or system.
The range within which the true value can be found.
An average calculated from a set of values.
The smallest change a piece of apparatus can measure.
A piece of equipment designed for a particular use.