1935 Visible creation of an invisible sine wave

With the benefit of hindsight it must have been during my high school days that my creative talents began to emerge and I feel it must have been my physics master Bill Sobey who sparked my interest. I remember him showing me an apparatus he had devised which transformed the energy of sound waves into a moving ray of light onto a screen – creating a moving visible trace of a sound. It was magic and I have remembered the apparatus and made one for my boys at some time.

It is a very simple system and possibly predates the electronic oscilloscope, probably going as far back as Leonardo da Vinci in the 15th century and my purpose in recording it here is in the hope that my grandchildren will have sufficient curiosity to make one to help them understand a very fundamental aspect of physics – and pass it on.