Archimedes Principle (Upthrust)

$$\begin{align*} \text{upthrust} &= \rho g V \\ &= \text{density} \cdot \text{gravitational acceleration} \cdot \text{volume} \\ &= \text{weight of liquid displaced} \end{align*}$$

Derived from:
upthrust = upwards force on bottom surface - downwards force on top surface

Float - The weight of water displaced > weight of object
Float - Upthrust > weight
Sink - The weight of water displaced < weight of object
Sink - Upthrust < weight