A free IB DP Physics skill pack on SI base and derived units (SL and HL, first assessment 2025): a rules reference, four worked examples and 56 answered practice items. Free means the whole pack, nothing held back.

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 a supplement to integrated teaching, not a taught unit.

This pack is worked, not taught: the teaching duration shown is student working time across the practice bank, about 145 minutes, not classroom delivery time. It splits into two sittings, about 80 minutes then 65.

What students learn:

• The seven base quantities and units, and what makes a quantity derived rather than base
• Building a named unit from its defining equation, resolving any named unit on the right first: a pascal takes two rounds, an ohm four
• Writing a unit the booklet’s way: negative indices rather than a solidus, and the space that makes m s^-1 a speed and ms^-1 a per-millisecond
• Checking an equation for homogeneity, and what it cannot catch: a pure number, a sign, or two quantities sharing a base-unit form
• Non-SI units (eV, ly, pc, h, day, year, degrees Celsius), and which conversions the booklet supplies

Three tiers: A, 38 fluency items in six sets; B, 12 applied parts where a named or non-SI unit must be handled first; C, four multiple-choice items, every distractor explained, and two structured questions worth 17 marks.

IB skills (Tool 3: Mathematics): taught are fundamental units, derived units in terms of SI units, checking an expression using dimensional analysis of units, non-SI units, and the symbols stated in the guide and the data booklet. Practised: arithmetic and algebra.

What’s included:

• Student Worksheet, 18 pages, answers stripped out, colour and B&W
• Teacher Key, 29 pages, every answer and solution, plus teaching notes
• The editable worksheet, 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:

• Unit Conversion, the companion pack on prefixes and compound units (free)
• Scientific Notation and SI Prefixes, the companion on the size of a number (free)
• Significant Figures and Rounding, the companion on precision (free)
• Proportionality and Scaling, the same relationship read for how it scales