30-page study workbook for Pearson Edexcel IGCSE Double Science Physics (4SD0, Paper 1P), covering all of Theme 3: Waves across 6 structured 30-minute sessions. Includes transverse vs longitudinal wave comparison, the wave equation v=fλ with 4-step worked examples, the Doppler effect, reflection ray diagrams with i=r law, refraction through a glass block with n=sin i/sin r, critical angle calculation using sin c=1/n, TIR conditions and optical fibres, the full EM spectrum with mnemonic including uses and dangers, and sound wave properties including ultrasound. Two complete practicals (ripple tank and refraction). 8 Common Error panels. 6 draw tasks. Answer Key covers all 24 practice questions.