I’ve been puzzling over two words that both can be translated as “experience” – das Erlebnis and die Erfahrung. I learned the first of these early on as I wanted to be able to describe my “experiences” with living in Germany and this word seemed to fit. Recently, I have been doing some online exercises about the German educational system and one of the key words that came up was die Erfahrung. As in English, this can be a section on one’s CV/resume (der Lebenslauf – worth a post in itself!) where you describe the different jobs, paid and unpaid, that you have done. Two German friends seemed surprised that I would find these two words confusing, they argued that die Erfahrung is associated with learning something new. In support of this they cited the proverb durch Erfahrung wird man kluge – “one learns by experience” or perhaps “through experience one becomes wise.”
My current hypothesis, based on this explanation, is that while you may set up the conditions that produce ein Erlebnis – going on a vacation or to a new restaurant or for a walk in the park – the “experience” just happens to you, you are somewhat passive. For it to be eine Erfahrung, you must put in some sort of effort, you don’t simply collect these “experiences,” you build them.
Earthquake Words/Erdbeben Wörter 
I think both meanings can occur through happenstance. The distinction between the words might be clarified if one thinks of them as follows: Meeting a celebrity would certainly be an erlebniss (result in being exposed to something unique), but it wouldn’t necessarily allow one to sammel erfahrung (gain experience). Meeting the Dalai Lama would probably qualify as both.
I would distinguish the first usage of experience is ephemeral, while the second implies something richer perhaps even informing the further development of the individual who had the experience.
Without erfahrungen one can’t learn or become wise, but mere erlebnisse would never produce such a result.
Ephemeral – that captures my hypothesis perfectly, thank you! Now, what would be your preferred translation of “ephemeral” be?