GCSE›AQA GCSE Physics›Mind mapsReflection, Refraction and Total Internal ReflectionAQA GCSE Physics: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsAt a boundaryReflection: wave bounces backAbsorption: energy taken inTransmission: wave passes throughEffects vary with wavelengthRefractionChange of direction at a boundaryCaused by change in speedAir → glass: slows, bends towards normalGlass → air: speeds up, bends awayDetection (HT)Ultrasound: reflected from boundaries in bodyEcho sounding: measures sea depthUses differences in velocity and reflectionReflectionrefraction and TIRPSSeismic waves (HT)P-waves: longitudinal, solids and liquidsS-waves: transverse, solids onlyBoth reflect and refract at layersEarth's core (HT)S-waves stop at liquidsPart of the core must be liquidEvidence for size and structure of coreExam tipsRefraction is due to speed changeNormal is at right angles to boundaryRemember: S-waves 'Stop' at liquids