How this calculator works
A spherical cap of height h occupies pi h^2(r-h/3). Each liquid supports the weight of the volume it displaces. At equilibrium the two buoyant forces add to the sphere weight. Setting upper-fluid density to zero gives a one-liquid experiment with negligible air buoyancy. Use measured solution densities; salt concentration alone needs a temperature-dependent density model. Surface tension, mixing and wall contact are excluded.
Formula
V = 4 pi r^3/3; V_lower = pi h^2(r-h/3); m = rho_lower V_lower + rho_upper(V-V_lower).
Worked example
A sphere with r = 0.05 m has volume 0.000523598776 m3. At an interface between 1000 and 1200 kg/m3 liquids, half-volume immersion supports mass 0.575958653 kg.
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Frequently asked questions
Can I use salt water?
Yes. Enter the measured density in kg/m3 or another offered density unit.
What if the object sinks?
If its density exceeds both fluid densities, there is no floating interface solution. The tool reports that condition.
Is a hollow ball allowed?
Yes, if it is rigid and sealed. Use its total mass and outside diameter.