This kit allows students to create Toroidal Vortex Rings using dry ice. A double vortex ring generator is also included to demonstrate the coalescing of the 2 rings. Topics for discussion include friction and pressure to explain how they occur, and their natural occurence in volcanoes and dolphins blow holes. The kit contains 10 single vortex generators, 1 double vortex generator and comprehensive teacher's notes. A minimum of 5kg dry ice will be required, but 10kg is recommended and needs ordering in advance.