Consider two hollow glass spheres, one containing water and the other containing mercury. Each liquid fills about one-tenth of the volume of the sphere. In zero gravity environment

In a zero-gravity environment, the behavior of liquids is primarily governed by surface tension and adhesive forces rather than gravity [t3][t8]. Water is a wetting liquid for glass, meaning its adhesive forces with the glass surface are stronger than its cohesive forces. Consequently, water seeks to maximize its contact area with the glass, spreading out to form a thin layer or coating on the inner surface of the hollow sphere [t2][t5]. Conversely, mercury is a non-wetting liquid for glass with a high contact angle (greater than 90 degrees). Its cohesive forces are much stronger than its adhesive forces with glass, causing it to minimize contact area. In microgravity, mercury will pull itself into a spherical shape and float freely within the sphere to minimize surface energy, rather than spreading across the walls [t2][t4].

Sources

1. [1] https://www.nasa.gov/wp-content/uploads/2019/10/iss-fluid_physics_tagged.pdf