this device a nano magnet in water vibrates randomly, which is
invisibly attached to another magnet located in honey (viscous
Falsification: This would break the 2nd Law of Thermo if the honey heats up and the water molecules slow down (cool). For this to not work, the honey would have to transfer heat back into the water immediately so that no temperature differential occurs over time. An insulation layer may be needed to block heat from transferring back into the water. If insulation can be used, it seems unlikely to falsify it this route. Another potential falsification of this device is that the micro magnet in the water simply moves slowly but does not continually slow down over and over. It would seem that if there is drag on the magnet it would slow down with time, while the honey heats up and randomly disperses heat eventually reaching the heat sink at the top. This device may be falsified in such a way that the honey never heats up and the magnet just slowly vibrates without continually losing speed. It would need to be empirically tested in a nano lab.
One can change the viscosity of the fluid to the desired property. The most likely falsification of them all seems that the magnet just slowly vibrates permanently but never continually slows down over and over. However one option to consider is that the device is not falsified, and it actually breaks the second law. Breaking the second law would falsify the second law, but the 2nd law would still hold true for most macroscopic systems. Since the 2nd law is scientific, it must be falsifiable and one cannot reject this device based on circular reasoning that the the 2nd law is just always true, since it could be that the 2nd law is not true in all cases. This viscosity differential device would have to be empirically tested in a nano institution to verify that it works to separate hot from cold. Insulating the device so that room temperature does not cause equilibrium is the only tricky problem with building the device. Otherwise it is extremely simple to build without complexity.