I was interested to see how he’d try to demonstrate this, but I came away with the same assumption I started on, which is that there’s no convincing, easy-to-see demonstration. The effect you’re looking for is so small, and that amount of light can produce so much heat, that it will never be obvious that you’re not seeing some thermal effect. Like, in that vacuum chamber test, I might be seeing the armature buckling, or evaporation from the foil surface, or convection in the less-than-perfect vacuum, or electrostatic effects due to thermionic emission.
I’m sure you can measure light pressure with precision instruments, I just don’t think you can do it in a way that’s both scientifically sound and interesting to look at.
