Harmonograms
By Rick Hall
The twin-elliptic harmonograph is a double pendulum thought to have been conceived by Professor Hugh Blackburn circa 1844: his intention was to devise an instrument which would record simple harmonic motion.
I built my harmonograph based on a model which I chanced upon whilst visiting the London Science Museum in 1995. It consists of two weights suspended from a fixed point: the weights are finely tuned so that their relative motion generates complex graphic figures.
The pen which records the movement of the ‘twin-ellipses’ is positioned at the focal point between the weights: both the mass and position of the weights are variable.
The harmonograph is highly sensitive to initial conditions and will never repeat the same path: like fingerprints, no two harmonograms are the same.
Click on any harmonogram throughout this website to enlarge.
