Yes, I had to test that! :-D

Top pic: Ice cubes (left) and leftover uranine solution from when I was preparing those ice cubes Bottom left pic: Melting the ice cubes in a water bath to see if they start glowing again when melting. Bottom right pic: Yes, they do! :-)

Why do I find this exciting? Because that means that a phase change of the water switches fluorescence as a tracer of that water on and off. Or the other way round: Seeing water fluoresce (or not) tells you what state the water is in without having to figure out anything else about that water.

…and funny how that the apprenticeship as chemical technician that I started in parallel to finishing high school (and didn’t finish because other stuff — oceanography — became more interesting) does come into play in the most unexpected moments :-)