More bubbles in microgravity
I find it interesting that, contrary to terrestrial experience with drops on a surface, the colliding drops tend to scatter rather than coelesce. In microgravity the drops are spherical, which is the minimum-energy configuration, so I expect this presents an activation barrier of sorts. The collision needs to be strong enough to perturb the shape of the drops, so that combining them doesn’t represent a configuration that requires more energy than is present.