Abstract: An energy generating device may include a first body portion with at least one first force input structure coupled to the first body portion and configured to receive an external force. The energy generating device also may include a second body portion, the second body portion rotatable relative to the first body portion. Further, the energy generating device may include an electrical generator configured to use the relative motion between the first body portion and the second body portion to generate electricity. The first body portion and the second body portion are configured to descend through a medium at least partially under the force of gravity or ascend through the medium at least partially by buoyant forces in such a way that the medium causes a force on the at least one first force input structure by impinging on the at least one force input structure causing relative rotation between the first body portion and the second body portion.