I like the fact that the bubbles are both the same colour and that the reflections are similar. I shot this early this morning out in a wide open space, yet close enough to a dark hedge (need a dark background). Nice to get strong green reflections in a blue bubble too!
You can actually see the early morning clouds more clearly in the small bubble, which is quite strange. The different sized bubbles tend to pick up the light differently. To me, it seems random how they do this, in that sometimes a small bubble will be darker than the large bubble and sometimes it will be brighter. There's no doubt some theory that could explain this.
The strangeness of these reflections actually reward some close viewing. Spend a while in there! Have a wander!
I was going to name this bubble 'Clean', because it's so clean. Lots of times when you blow a bubble inside a bubble, bits stick to the side, or tiny bubbles of different colours get stuck between the larger bubbles. They're nice in their own way, but it's also sweet to get a more simple and minimalist shot like this one.