http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/waves/soundandlightrev1.shtml
Source: http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/waves/soundandlightrev1.shtml
A short lesson about musical sounds
Source: Mrs G Boyson: http://www.knowmia.com/watch/lesson/45686