You know bubbles. It is just air entrapped by some kind of liquid. We loved it when we were younger as we try to pop every single we see. A delicate swoosh of air can explode it, so capturing the action in a photograph is a deal with timing.
Bubble photography amazes me. It takes a simple act of joy to the level of immense creativity. Tom Falconer’s flickr has a great set of bubbles in photos.