## Overview This topic covers the basic ideas of electric charge and electric current. The nature of charge carriers in conductors is explored. ## Mathematical Skills There are a number of opportunities for the development of mathematical skills in this unit. These include recognising and using expressions in decimal and standard form; using ratios, fractions and percentages; making order of magnitude calculations; calculating areas of circles, surface areas and volumes of rectangular blocks and cylinders. ## How Science Works There are opportunities within this topic for learners to use theories, models and ideas to develop scientific explanations. ### Learners should be able to demonstrate and apply their knowledge and understanding of: (a) the fact that the unit of charge is the coulomb (C), and an electron's charge, e, is a very small fraction of a coulomb (b) the fact that charge can flow through certain materials, called conductors (c) electric current being the rate of flow of charge (d) the use of the equation Q I t  =  (e) current being measured in ampères (A), where A = C s -1 (f) the mechanism of conduction in metals as the drift of free electrons (g) the derivation and use of the equation I nAve = for free electrons #Component2