The Kaye effect revisited

WHEN a thin stream of certain solutions of polyisobutylene in dekalin is poured on to an open evaporating dish, a heap of the liquid forms at the point of contact with the dish. As pouring proceeds a small streamer of liquid emerges from the heap, leaving it at a low trajectory, which gradually steepens before the streamer collapses. The whole effect lasts for about one second 1–3 . Using a new filming technique and a film speed of 250 frames s −1 , we have observed that the emergent streamer is really a loop of liquid, and we here propose a mechanism for this effect. The second frame in Fig. 1 shows the effect. Such looping of the emergent streamer is not unexpected as the liquid is pituitous. In the following frames the loop extends outwards until the bottom of it strikes the surface of the liquid on the flat glass plate. As the streamer is cutting off the liquid from the heap, the heap collapses and flattens, presenting a smaller angle of incidence to the incident stream and causing the bouncing streamer to steepen in trajectory and move azimuthally, as suggested by Kaye. The base of the streamer's trajectory is often as large as 100 mm.