Robins' demonstration ballistic pendulum

Shan Macdonald, Curatorial assistant for Scientific Instruments selected this object from the Hunterian Museum's collection. Shan writes - This wooden frame was used in teaching at Glasgow University's Department of Natural Philosophy (the subject now called Physics) to determine the momentum, kinetic energy, and velocity of a bullet in flight by using a known mass over a set distance.

The apparatus was invented in 1742 by the English mathematician Benjamin Robins. William Thomson (Lord Kelvin) regularly demonstrated the apparatus using his Jacob militia rifle resting on the pendulum guard. His rifle, still in its case with embossed brass powder horn, is also in the collection of the Hunterian Museum.

The guard of this particular ballistic pendulum is slightly damaged due to inaccurate shooting over successive teaching generations.