How this calculator works
Full immersion displaces the outside volume of the object. Subtract the displaced-fluid weight from true weight to obtain the required support force. Dividing by gravity gives the apparent scale mass. A negative result means the object needs downward restraint. The comparison table uses rounded textbook reference states; household oils, syrups and detergents vary with composition, so use their measured density in the main input. Ballast adds both mass and displaced volume.
Formula
m_apparent = m - rho_liquid V; W_apparent = g(m-rho_liquid V). Neutral-ballast volume = max(0,(rho_liquid V-m)/(rho_ballast-rho_liquid)).
Worked example
A 10 kg object displacing 0.001 m3 in 1000 kg/m3 water has apparent mass 9 kg. At g = 10 m/s2 its support force is 90 N and buoyancy is 10 N.
Advertisement
Frequently asked questions
Is immersed weight a mass?
The support force is in newtons. The apparent mass is the equivalent reading of a mass-calibrated scale.
What if the object is less dense than the liquid?
It rises unless restrained. The signed support force becomes negative.
Can I use rubbing alcohol or honey?
Yes. Enter a measured density for the particular mixture and temperature; their names do not specify one reliable density.