Uncertainties in measurements: chemistry
I can explain why there is some uncertainty when measurements are made, how to minimise uncertainty, and calculate uncertainties.
- Year 10
- AQA
Uncertainties in measurements: chemistry
I can explain why there is some uncertainty when measurements are made, how to minimise uncertainty, and calculate uncertainties.
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
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Which piece(s) of laboratory equipment are typically used for measuring volume?
Q2.Which mathematical operation(s) would you use to calculate the average of three measurements?
Q3.In an experiment, what type of variable is the one that the scientist changes?
Q4.In an experiment measuring the effect of sunlight on plant growth, what is the dependent variable?
Q5.Significant refer to the digits in a measurement that are known with certainty plus the first digit that is uncertain.
Q6.Match the following terms with their correct definitions:
Assessment exit quiz
6 Questions
Q1.What does the uncertainty of a measurement indicate?
Q2.Match the term to its correct definition.
