# Drop tower setup to study the diffusion-driven growth of a foam ball in supersaturated liquids in microgravity conditions

## TL;DR

This study investigates the microgravity-driven growth of foam balls in supersaturated liquids using drop tower experiments, providing insights into foam dynamics relevant for space manufacturing and celestial geology.

## Contribution

It presents an experimental setup in a drop tower to observe foam growth in microgravity, revealing foam size scaling over extended times beyond Earth's gravity influence.

## Key findings

- Foam size scales with time in microgravity conditions.
- Gravity influences foam dynamics within milliseconds on Earth.
- Preliminary results extend understanding of foam growth in space-like environments.

## Abstract

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.