Unit 1. Physical quantities and units - Part 1The measurement and recording of quantities is central to the whole of physics. The skills of estimating a physical quantity and having a feeling for which quantities are reasonable and which are unreasonable are very useful for any physicist. This topic introduces the SI system of units, which provides a universal framework of measurement that is common to all scientists internationally. Candidates should be aware of the nature of a physical measurement, in terms of a magnitude and a unit. They should have experience of making and recording measurements in the laboratory.