When I first learned about bowl feeders I thought that there was some sort of rotation that would cause it to go up, but apparently it is caused by vibrating the bowl.
I do not understand how vibrations can cause a part to move upwards. From what I understand, vibrations will have a similar effect to reducing friction, which means that it would cause the parts to fall down the slope more easily.
How does it work? Is the vibration applied in a certain direction/rotation/etc. which causes this upward movement? Or is it just normal vibration?