Professor David Howard, Head of the Department of Electronic Engineering at Royal Holloway, presented a talk at the British Library Knowledge Centre to an enthralled group of 9-12 year-olds for “Science on Stage” for the Benjamin Franklin Society.
Professor Howard demonstrates Franklin’s Glass Armonium
The subject of the talk was Franklin’s Glass Armonium (an adaption of the Glass Harp).
History records that Benjamin Franklin heard a glass harp (set of wine glasses with different levels of water in them to tune them to a musical scale that are played by rotating a wet finger around the rims of the glasses) and came up with an ingenious solution to enable (1) musical chords to be played much more easily, and (2) tuning to be fixed (removing tuning changes as the water evaporates).
Franklin had glasses specially made so that they were permanently in tune after manufacture. He then mounted these glasses close together on a horizontal axel that could be rotated using a pedal with a crank (rather like the old treadle sewing machines) to enable the player to reach many more glasses with each hand. He called his instrument the Glass Armonica after the Italian word for ‘harmony’ (armonia). The high pitch ethereal sound of the Glass Armonica was said to be spooky, reportedly causing illness, muscle spasms, nervousness, and driving some listeners mad. In some places it was banned!
In his talk, David demonstrated the acoustic make-up of the output sound, and established a link with speech, commenting,
“The topic proved very popular and having demonstrated the principle of the glass harp with a wine glass a number of students were very keen to have a go themselves! “
The Department of Electronic Engineering is actively involved in outreach and taster activities to inspire the next generation of young scientists.