What determines the shape of water during free fall?
Due to surface tension, a property that minimizes surface area, liquid would become spherical if allowed to free fall without the Earth’s gravity. On Earth, gravity overpowers surface tension, and liquids form flat surfaces. However, in very small areas (capillary tubes less than 5 mm in diameter, such as thermometers) surface tension dominates and liquids form spherical (convex or concave) surfaces.
