How does it work:
The current moving through the copper conductor naturally generates an orthogonal (right hand rule) magnetic field, which opposes that of the permanent magnet, causing a force to push them away from each other. Notice the way the ‘bottom’ of the copper wire is shaped such that it comes in sideways before it touches the magnet, this part is where the magnetic field is generated which opposes that of the permanent magnet, the rest of the generated magnetic field is essentially not used, which is why this is a relatively inefficient motor. every DC motor you’ve ever used (e.g. computer fans) operate on this same principle.
Similarly, if you hooked up a multimeter to a the ends of a disconnected ring of conductor (copper), then moved a strong permanent magnet through the ring, it would induce a current, and in turn a voltage differential that would be measurable on the multimeter. This is an example of magnetism generating electricity, whereas with the homopolar motor in the video electricity is generating magnetism. These two phenomena happen trillions of times a second in an EM wave like light and allow light to move through space or other media.