The Problem I'm doing Salters A2 Physics coursework. Have chosen to do attenuation of projector slides but need some help with project variation. I feel that just finding an attenuation coefficient for the material that the slides are made from will give me few measurments and therefore not maximise my potential marks. Will there be any difference in the attenuation coefficient for different wavelengths of light? If this is worth investigating should I use a filter on the light source or coloured slides? How else can I increase the diversity of my investigation?