My question relates to this video illustrating the Heisenberg uncertainty principle.
The video shows light being shot through a slit forming a spot on a screen. As the slit narrows, the width of the spot narrows, until eventually the width of the spot starts increasing. The person in the video says this is counterintuitive.
I'm slightly puzzled as to why this is counterintuitive. Isn't this just like classical single-slit Fraunhofer diffraction, which would work with water waves?
So what I'm guessing is the experiment is counter-intuitive using a particle view of light?
So does this mean Heisenberg's Uncertainty principle is somehow equivalent to wave-particle duality?
Looking to clarify if my thinking is correct.