GCSE Physics lesson on Resistance, designed for AQA specification but suitable for various exam boards, difficulties and key stages. Includes an introduction to the concept of resistance, the equation used to calculate it from potential difference and current, instructions on how to use a formula triangle, and plenty of practice questions. Easy to teach for a teacher not specialised in physics, with no printing and minimal preparation required. The practice questions are differentiated according to the difficulty of the calculation involved.