Inspired by the infamous Queensland Pitch Drop Experiment and the Johnny-come-lately Pitch Drop experiment at Trinity University, Andy Gibson (@Lopek) created his own version of the experiments using Silly Putty, and then tweeting about it. The result has been put together in Storify and it is pretty interesting to look at. Here are my comments on what is occurring as the experiment proceeds. Rheologically, of course.
First off, I am not commenting on every single picture available, just certain key elements. Also, note that the geometry chosen has a major influence over what you see. If the funnel was higher off the desk, the results could vary. The same goes for the diameter of the outlet (more about that specifically in a minute), the slope of the funnel and the amount of Silly Putty used. Temperature would also affect the results, but I'll leave that topic for another day (if ever!). Change any of these and you could generate completely different images. There is another geometric variable that would be interesting to see sometime too, but I'm not going to mention it now. I'll try and set up the experiment myself and then expand on that topic.
Experiments such as these are a gobbled-up mix of shear, elongation, surface tension and other forces at work, all being influenced at different rates. You should see some similarities with the Pitch Drop experiments, but as the geometries of the funnels and the rheology of the materials are different, there is not an exact 1-to-1 correspondence.