IB DP Physics skill pack: uncertainties. Recording, absolute and percentage uncertainty, and propagation through the four rules. SL and HL, 2025 syllabus. Four full worked examples, 25 answered items and 76 keyed drill cells, in a 29-page student worksheet with a 40-page teacher key. This is the arithmetic of uncertainty, drilled on data of every kind so that the method is not tied to any one experiment.

What this pack is, and what it is not
The IB guide asks for these techniques to be practised inside the topics and the investigations that need them, so this is not a taught unit of the course and does not claim to be one. It is reference and remedial material for a technique the whole course assumes: it supplements integrated teaching rather than replacing it. It earns its place just before the first practical of the year, again as revision before the internal assessment and before Paper 1B, and any time a student is losing marks on the technique rather than on the physics.

This pack is worked, not taught: the 190 minutes quoted is student working time across the practice bank, not classroom delivery time. Set it as homework and practice rather than as a timed classroom activity.

Where this pack stops
It is the arithmetic of uncertainty, and it is complete on that: what an uncertainty is, where it comes from, how it is written, how it travels through a calculation, and how a finished result is compared with an accepted value. What uncertainty does to a graph is not here. There are no error bars, no lines of maximum and minimum gradient, no uncertainty in a gradient or an intercept, and no linearising of a curve.

What students learn

• Seven words that are not synonyms. (Accuracy, precision, resolution, uncertainty, error, reliability and validity)
• Recording a reading, before any uncertainty is worked out.
• One uncertainty, three ways of writing it. (Absolute, fractional and percentage)
• The four propagation rules.
• Percentage error, percentage difference, and whether a result agrees.

IB skills this pack teaches and practises
The significance of uncertainties in raw and processed data.

• Recording an uncertainty as a range (±) to an appropriate level of precision.
• Propagating uncertainties through addition, subtraction, multiplication, division and raising to a power.
• Expressing an uncertainty as an absolute, a fractional and a percentage uncertainty, to an appropriate precision.
• • Assessing accuracy, precision, reliability and validity
• Calculating and interpreting percentage error and percentage uncertainty.
• Calculating and interpreting a percentage difference
• Calculating mean and range.
• Identifying and discussing sources and impacts of random and systematic errors

What’s in the pack

• Student Worksheet (29 pages)
• Teacher Key (40 pages)
• The editable worksheet

Written against the IB DP Physics guide (first assessment 2025) at both Standard and Higher Level.