This worksheet teaches students to identify the impact of measurement error on accuracy, calculating absolute and percentage error and how that error carries through into a derived area, volume or speed. The worksheet is split into warm-up questions, standard questions and then extension questions to test you.
The concepts it covers:
- Every physical measurement has some uncertainty — the absolute error is typically half the smallest division on the measuring instrument.
- Percentage error = (absolute error ÷ measured value) × 100% — it expresses the error relative to the size of the measurement.
- The true value lies somewhere in the range [measured value − absolute error, measured value + absolute error].
- The same absolute error produces a smaller percentage error on a larger measurement — so precision (percentage error) isn't just about the instrument, it's about the size of what's being measured too.
- When a measurement error propagates into a derived quantity (area = product of two lengths, volume = product of three), the error compounds — the derived quantity's error is generally larger, proportionally, than the original length's error.
What your child will practise:
- Finding the absolute error of a measurement from the precision of the measuring instrument.
- Calculating percentage error, and use it to compare the precision of different measurements.
- Finding the minimum and maximum possible true value(s) given a measurement and its absolute error.
- Finding the minimum and maximum possible value of a derived quantity (area, volume, speed) by combining the extreme values of each input measurement correctly.
- Evaluating whether measurement uncertainty actually changes a practical decision (e.g. how many tiles to buy).
Every section opens with a worked example, and the download includes a full answer key with step-by-step solutions and teaching notes on the mistakes students most commonly make.
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