At The Pump

Did you ever play with Silly Putty™ as a kid? Silly Putty is a bizarre polymer, and seems to like switching back and forth from gooey almost-liquid to bouncy almost-solid. But like most polymers, it has a transition temperature at which its physical properties change. In this case, there is a glass transition temperature T_g, below which Silly Putty will behave like glass, and shatter instead of squishing.

Often, the viscoelastic properties of polymers have a rate dependence, and this is the case with Silly Putty. Do the same amount of work over a shorter period of time -- say, hit it with a hammer instead of squishing it between your butt cheeks -- and Silly Putty behaves as if its T_g has been raised. It'll blow into a million pink bits. Don't get it in your hair.

Another cool thing you can do with Silly Putty is squish it onto a comic book or a newspaper, and a ghostly reproduction of the image will be transferred onto the Putty. If you squish it around for a bit, the image will appear to dissolve, but your Putty is a little less pink now. Do this enough times and it'll turn an ugly shade of gray.

Silly putty also bounces, stretches and flows. It is very resilient.

So with all of these wonderful, seemingly magical properties, Silly Putty seems to me to be the perfect metaphor for ... something. But what?