A water-powered generator having a vessel and a variable density body situated within the vessel. The vessel is partially filled with a fluid, such as water. The variable density body moves between a first position near the bottom of the vessel to a second position between the bottom of the vessel and the top. The variable density body is configured to have a changeable total density such that the total density may be changed from a first density which is greater than the fluid and a second density which is less than the fluid. The movement of the variable density body is converted to a useful form of energy, such as electric current.