I vaguely remember having tried this myself with a very small aquarium and liquid latex (IIRC), filmed with my Super 8 cam in slow motion (which meant 36 frames instead of 18).

The results weren't that impressive, but it was fun, as was all the Super 8 stuff. I kind of miss those times and I see at least one other poster seems to have similar recollections :)

To add another nice example of this effect, which is where I learned about it, is The NeverEnding Story (1984). There it's used for the "nothing" (https://www.youtube.com/watch?v=rPfQogtS2Eo) and also in the opening of the US release (https://www.youtube.com/watch?v=CCgfRC6gHtI). The original German release only had text on a black background.

It might not look the most realistic, but IMHO it still looks beautiful.