  The diffusion-driven growth of a foam ball is a phenomenon that appears in
many manufacturing process as well as in a variety of geological phenomena.
Usually these processes are greatly affected by gravity, as foam is much
lighter than the surrounding liquid. However, the growth of the foam free of
gravity effects is still very relevant, as it is connected to manufacturing in
space and to the forma- tion of rocks in meteorites and other small celestial
bodies. The aim of this research is to investigate experimentally the growth of
a bubble cloud growing in a gas-supersaturated liquid in microgravity
conditions. Here, we describe the ex- periments carried out in the drop tower
of the Center of Ap- plied Space Technology and Microgravity (ZARM). In few
words, a foam seed is formed with spark-induced cavitation in carbonated water,
whose time evolution is recorded with two high-speed cameras. Our preliminary
results shed some light on how the size of the foam ball scales with time, in
particular at times much longer than what could be studied in normal
conditions, i.e. on the surface of the Earth, where the dynamics of the foam is
already dominated by gravity after several milliseconds.
