|Greetings from the Critique Club
Interesting image. Lava lamps are so much fun to watch. I like the colours, the purple globs, the gold outline. I also like it that the background works both as a background and as a frame.
I think the exposure is right on for what you seeminly wanted to achieve. It was a wise decision to use a tripod, because at 1/5 of a second, handheld would not have worked. The colours are beautiful, quite rich, and the black is deep. I like the specks, they add life to the whole thing. I'm not sure how you processed this, but one thing that might help a bit is to sharpen the image a tad - the bubbles look a bit soft.
As for the challenge, it meets the challenge in that there are bubbles in the image. It might be that not everybody recognizes these as bubbles though, especially during voting, when images only get a few seconds viewing from each voter. The image doesn't really "sell" the idea of bubbles, in other words, it doesn't scream, "bubbles!"
Overall, a pleasing image, but it could be a bit sharper. A good entry to the challenge, but without selling the concept.
I hope this helps. If you have questions, complaints, comments, feel free to contact me.