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A couple of nuclei have spin-isomer (IIRC) decays that emit both the expected high-energy photon, but also a second visible one. I no longer remember which. :/ The challenge with seeing a single atom naked-eye, is getting visible photons fast enough. For some value of see - it's just a point source. I had a professor object "that's not seeing the nucleus - it's just a diffraction-limited dot". Funny thing was, they were about to travel to a big star party, to I guess "not see" stars. Sigh. Admittedly the argument for pedagogical value is limited. But at least the years-later long-exposure photo of a single atom was interesting enough for popular press. With an atom's electrons, the bottleneck is electron transition cycle time. So your photon budget is small and isotropic. And the retina requires localized hit(s) on deadline. With an pumped atom outside the eye, even with optics, my impression is you at best have a limits-of-perception experiment: "ok, I've a 50% confidence (my dark-adapted eyes) just saw a flash there". Nuclear transitions are plenty fast. But they're also higher energy, and you can't see X and gamma rays. Well, except for the flash of retinal cell death, as with cosmic rays in astronaut eyes. So with a nucleus that emits visible photons, you can tweeze, trap, strip and bombard an atom to fluorescence in a vacuum chamber, have a window that passes visible, and get a little dot, naked-eye visible with ambient room illumination. It's a cover photo somewhere IIRC, but I years back burned out on trying to re-find it. But it's a fun concept, isn't it? And makes for a compact example of needing expertise. More compact than say a marine bio professor, writing a children's picture book on photosynthesis, burning lab time to figuring out what bottlenecks world phytoplankton mass. But they're sort of toy examples. Real need is more like being able to ask "Instead of an atoms-up primary school learning progression, might we do nucleons-up to materials? What might that look like? What stories might we use? What cross-cutting ideas might tie it together?". I wish I knew how to make progress on this. |