How big is a phone book, and other ways of illustrating size

In terms of representing scale, one of the most powerful mechanisms I find useful is to use examples people can grasp in meaningful terms. In the Boston seminar, ET uses the “amount of data in a phone book” as one of those conceptual hooks. I think I caught him say that a typical phone book contains 38,000 characters. Did I hear that right?

And, while I raised the topic, do you have other credible examples of this kind of metric? For example, I’m trying to explain to people how much a terabyte of data is; the best example I have found so far is that the entire Library of Contents is estimated to be about 10 terabytes of data. That’s a good way to make that staggering number real.

And, today, I heard another one, that there are about a billion bags checked for air travel, world wide, in a year.

I’m curious if anyone else has some favorite ways of representing scale in concrete, understandable terms.