And then they go down, and they go hunting for fish... [I]t comes time to go back up to the surface and hop out onto the ice past the s. - Helen Czerski

So this is brilliant, because it's this wonderful interaction of all sorts of things. It's a physical process. The reason the bubbles come out as the penguin swims up is because the pressure is decreasing, and the bubbles are expanding, so they can come out of the feathers.

This is why I love physics. Everything you learn will come in useful somewhere else, and it's all one big adventure...

[W]e're past the point now where we say you have to go to sea to be an oceanographer, because it's not true, and it's actually very important that it isn't true.