The Kelvin Water Dropper: Converting a physics toy into an educational device

Abstract

The Kelvin Water Dropper was discovered by Lord Kelvin in 1867 and it works on the principle of electrostatic induction. A working model of Kelvin Water Dropper is fabricated in the workshop facility of Physical Research Laboratory, Ahmedabad. We, for the first time, performed a quantitative measurement of the temporal development of charge using a new method that we call "Effective Capacitance method". With this, the Kelvin Water Dropper experiment can be introduced in undergraduate curriculum, where students can perform quantitative measurements with the apparatus using our "Effective Capacitance method". This should change the generally held view of Kelvin water dropper as being an entertaining toy to a mature educational device.