When black sand is not agitated, there is no true panning

This short educational video will show black sand in the pan, but it is not agitated. There is shaking and movements of hands and the Garrett Prospecting Pan. Yet one can see that the black sand in the gold pan is not agitated. It does not move as slurry. It is not liquid and not stirred with the water.

Gold particles inside of this non-agitated black sand are trapped and have no space nor time to fall into the riffles and to get into concentration.

This will tell you that shaking has the purpose to agitate the soil or black sand in the gold pan so that gold particles may be concentrates at one spot underneath.