Giant soap curtains for public presentations

Hydrodynamicists have produced giant soap curtains for laboratory research and adapted them to public presentations. For the World Year of Physics 2005, we have automated their method. We have made thousands of 10, 15 and 18 m high soap curtains, with width up to 4 m, surface up to 34 m 2 and lasting up to 20 min. We explain here the methods we use, from the simplest one, a 2 m high curtain you can prepare in 30 min in your kitchen, to the most elaborate. We review some pedagogical projects which have been stimulated by soap curtains and suggest how to have a lot of fun. The present paper is thus a complement, oriented towards public presentations, of Rutgers et al 's more specialized article (Rutgers M A, Wu X L, Daniel W B 2001 Rev. Sci. Instrum. 72 3025).