How much? It’s one of those basic journalism questions, but when it comes to many science stories, it can be a tough one to answer in meaningful way. In most of my writing and reporting, I’m trying to find analogies to describe features smaller than the eye can see. But on the macroscale– like with the current oil spill in the Gulf of Mexico– comparisons are equally challenging.

This weekend, NPR’s On The Media looked at how reporters have characterized the size, scope, and political implications of this environmental disaster. Here’s a piece of the size discussion:

BROOKE GLADSTONE: Jackie Savitz, a senior scientist with Oceana, an international ocean conservation association, says that describing the scale of the leak in geographical terms, or how it looks from outer space, gives the public an incomplete understanding of the spill’s true dimension.

JACKIE SAVITZ: It may paint a picture of an area on the surface of the ocean that’s the size of Delaware, to the exclusion of all that area down below the surface, where lots of fish and other marine animals live who are also being exposed to the contamination. It might be more telling to think of it in terms of volume, like how many Olympic-sized pools is that or how many stadiums would that be, or what lake might that be equivalent to.

BROOKE GLADSTONE: Does the fact that can see it from space actually convey anything meaningful?

JACKIE SAVITZ: Most people don’t really have a sense of how far away space is, and even when you say it I’m not really sure how far away you’re talking about. Is it a satellite that’s circling the Earth or are you seeing it from the moon, right?

Yet another reminder to think carefully about analogies to thread that needle between cliche and useful comparison.

Listen to the whole segment here.