Final answer:
A perpetual motion machine violates the law of conservation of energy and is not possible according to the first law of thermodynamics. A filling buoyant object that sinks when filled and releases when bottoming out would require energy input and eventually stop. The drinking bird toy operates based on evaporation and condensation, needing an initial energy input as well.
Step-by-step explanation:
A perpetual motion machine is a hypothetical machine that can operate or produce useful work indefinitely. However, according to the first law of thermodynamics, energy cannot be created or destroyed, only converted from one form to another. Therefore, it is not possible to create a perpetual motion machine that violates the law of conservation of energy.
In the case of a filling buoyant object that sinks when filled and releases when bottoming out, it would require energy to fill the object and release it again. This energy input would eventually lead to the object running out of energy and stopping. Thus, it would not be a perpetual motion machine.
For example, let's consider a similar device called the drinking bird. It appears to be a perpetual motion machine as it continually dips its head into water and returns to its original position. However, the drinking bird operates based on the evaporation and condensation of the fluid inside it, involving an energy input to wet its head. Without this initial energy input, the bird would not be able to continuously move.