An IB DP Physics skill pack on uncertainties (SL and HL, first assessment 2025): a rules reference, four full worked examples, three figures and 25 answered practice items.

It is the arithmetic of uncertainty, drilled on data of every kind rather than inside one experiment, so the method transfers to any data set.

The syllabus assumes this technique but no topic owns it: the IB asks for it to be practised inside the topics that need it, so this is not a taught unit of the course but a supplement to integrated teaching.

This pack is worked, not taught: the teaching duration shown is student working time across the practice bank, about 190 minutes, not classroom delivery time. It runs as four sittings, 34 to 63 minutes each.

What students learn:

• Accuracy, precision, resolution, uncertainty, error, reliability and validity told apart, and random error against systematic error
• Recording a reading to the resolution of its instrument: scales, digital displays, two-ended lengths, hand timing and repeated readings
• Absolute, fractional and percentage uncertainty, converted both ways, and quoting a value to the precision its uncertainty supports
• Propagation through sums, differences, products, quotients, powers and exact numbers, and why subtracting two close values wrecks a result
• Percentage error against an accepted value, percentage difference between two results, and the range test that decides whether a result agrees

Where it stops: this pack is uncertainty arithmetic. Error bars, extreme gradient lines, gradient and intercept uncertainty and linearising are not covered.

Three tiers: A, six fluency tables with 76 keyed answer cells and a four-part error hunt; B, five applied items with 15 marked parts; C, three multiple-choice items with every distractor explained, and two structured questions worth 22 marks.

IB skills (Tool 3: Mathematics, with Inquiry 2 and Inquiry 3): the pack teaches the significance of uncertainties, recording them as a range, propagating them, expressing them in all three forms, percentage error, and assessing accuracy, precision, reliability and validity. Students practise mean and range, percentage difference, and identifying random and systematic errors.

What’s included:

• Student Worksheet, 29 pages, answers stripped out, colour and B&W
• Teacher Key, 40 pages, every answer and model solution, plus teaching notes
• The editable worksheet as a self-contained HTML file

Worksheet and key are two projections of one source, so no answer file can drift. Grades 11-12 (ages 16-19).

Related resources:

• Uncertainties on a Graph, the pack that picks up where this one stops
• Measuring the Acceleration of Free Fall, the practical that uses it (free)
• SUVAT Equations I, where the propagation is exercised