Originally Posted by

**Cragyon**
Density = Mass / Volume

or

p = m / V (a)

Density change

*E = - dp / (dV / V*_{0})

* = - (p*_{1} - p_{0}) / ((V_{1} - V_{0}) / V_{0}) Equation A

Where:

*E = bulk modulus - liquid elasticity (N/m*^{2})

The minus sign corresponds to the fact that an increase in the pressure leads to a decrease in volume.

With* (A)* - the final volume after pressure change can be expressed as

*V*_{1} = V_{0} (1 - (p_{1} - p_{0}) / E) (Ab)

Combining *(Ab)* with *(a)* - the final density can be expressed as:

*ρ*_{1} = m / (*V*_{0} (1 - (p_{1} - p_{0}) / E))

These are the equations you need to calculate the amount of pressure you need to float an object..