Since you seem to have done some experiments, what effect does increasing the bottle size have on the glow? Duration or brightness changed? No visible effect?
You max out pretty fast. Most people don't understand the incredibly wide (over so many orders of magnitude) ranges our eyes (and ears) function over. Once you're in the dark, the glow is quite visible but it wouldn't have been very notable before. And so the absorb-release cycle can penetrate rather rapidly. If I had to guess, with the gravel, that would die off at maybe a few centimeters of depth.
Essentially, you're getting just surface area at a given brightness, despite the interior gravel getting charged.
With the zinc sulfides, they really did take much longer to hit their max charge, although I never measured it.
> Most people don't understand the incredibly wide (over so many orders of magnitude) ranges our eyes (and ears) function over.
For sure. Last year while walking through the woods on a cloudy, new moon, 3am morning I saw a green light piercing through the trees. It was difficult to find because it was over a hundred feet away. Once I reached it, I found a single green LED. It wasn't an ultra-bright variant or anything-- just a normal LED attached to a camera.
I wonder, if one were to specifically design some kind of lamp based on this, what would be the ideal shape to maximize the emitted useful light for a given volume.
