Thomson's jumping ring experiment

This project is being designed for SciWorld a South Australian not-for-profit organisation full of people who are passionate about science. They provide science outreach programs in various locations around Adelaide and South Australia. 

The jumping ring experiment demonstrates how a conducting non-magnetic ring can be thrown into the air using an alternating magnetic field. The well-known experiment was originally discovered by Elihu Thomson an English engineer and inventor (March 29, 1853 – March 13, 1937).

An aluminium, copper or brass (non-magnetic) ring is placed over an iron core with a coil at the base. The coil is connected to an alternating current (AC) supply and when switched on the observer(s) will see the ring jump quickly into the air reaching a height of about 1 meter.

The height of this jump can be dramatically increased by cooling the ring to the temperature of liquid nitrogen (-196 °C). The ring may easily jump to a height well over 6 meters!

The coil, the ring and the core act as a transformer. The ring in this case can be considered as the secondary coil. The induced current in the ring produces a magnetic field in such a way that the ring is repelled. A stronger magnetic field is produced when the ring is cooled, so it will jump to a greater height.  At low temperatures, metals will have lower electric resistance and so electric currents can reach higher values, and so the repelling force will be stronger.

Draft design in planning stages - 07/12/2104