b'Branch newsASEG newsASEG national calendarDate Branch Event Presenter Time VenueNov WA Annual Student Presentation Night Various 17:30 TBA28 Nov ACT Christmas party and Tech talk TBA 17:00 Geoscience Australia, Symonston & Rubicon, Griffith,Canberra29 Nov SA-NT SAEMC Various Adelaide Convention Centre, Adelaide05 Dec TAS Tasmania Geoscience Forum Various 09:00 Tidal Waters Resort, 1 Quail St, St Helens05 Dec QLD Christmas drinks 16:00 Jade Buddha, 14/1 Eagle St, Brisbane06 Dec WA ASEG-PESA WA 32nd Annual Golf Classic08:30 Joondalup Resort, Country Club Boulevard, Connolly08 Dec SA-NT Geofamily Christmas in the Park 10:00 Point Malcolm Reserve, 343 Military Road, Semaphore11 Dec NSW Quiz night Various 17:30 99 on York Club, 99 York St, Sydney12 Dec SA-NT Mentor wrap-up, Honours night andVarious Hotel Richmond, AdelaideChristmas partyDec WA AGM and Christmas party Various TBA TBA12-14 Feb TAS GMS InSAR Workshop Berhard Rabus and Nick09:00 HobartRoberts21 WA GSWA Open Day Various 08:30 Esplanade Hotel, FremantleTBA, to be advised (please contact your state Branch Secretary for more information).Henderson byte: Galvani and VoltaRecently I was in Bologna, Italy, the home of Luigi Galvani (17371798) who was a pioneer of animal electricity. A statue in Luigi Galvani square shows him holding a plate on which there is a frog. In 1780 Galvani observed that frogs legs twitched and retracted when two probes of different metals were applied across them to form a circuit. He attributed this to a new phenomenon, which has been called bioelectricity or, more recently, electrophysiology, a field that today still studies the electrical patterns and signals from tissues such as the nerves and muscles. Along with his contemporaries, Galvani regarded the activation of muscles as being generated by an electrical fluid that is carried to the muscles by the nerves.Onto this scene came Alessandro Volta (17451827) a professor of experimental physics in the University of Pavia, near Milan. Atfirst Volta embraced the theory of animal electricity. However, he began to doubt that the contractions were caused by a specific electricity intrinsic to animals legs or other body parts. Rather, he believed that the contractions depended on thetwo-metal cable Galvani used to connect the nerves and muscles in his experiments.Volta demonstrated that when two different metals are separated by a brine-soaked cloth they produce an electric current chemically. He realised that the frogs legs merely served as a conductor of electricity, or what we would now call an electrolyte. Such a configuration is called a galvanic cell (sic), or voltaic cell.In 1799 Volta stacked several pairs of voltaic cells together through which an electric current flowed in what became known asvoltaic pile (the French word for battery is pile). Thus, Volta had invented the first battery, which he then used to disprove Galvanis theory of electricity being intrinsic to animals.The requirement that the metal electrodes be of different metals is a recognition of their different electrical potentials. The amount of difference is the electromotive force, or emf, of the cell. It is after Volta that the SI unit of electric potential is named as the volt (V).Galvanis name is not used officially for a standard unit in physics, however it has provided us with the verb to galvanise, meaning to stimulate or energise.Roger Henderson rogah@tpg.com.auDECEMBER 2019 PREVIEW 12'