Why did it take eight years to see that drop?

At room temperature, pitch may appear solid. We can even break it. Thomas Parnell at the University of Queensland, however, wants to show that it flows, at an extraordinarily low speed.

In 1927, he poured heated pitch into a closed funnel. He lets it stabilize for three years before opening the bottom. The first drop then takes eight years to fall.

The editing looks like an experience that could be installed for a course. His pace, on the other hand, exceeds the duration of a student’s studies. Temperature influences the flow, and the observations extend over generations. The pitch does not deceive us: it is our usual time of observation that is too short to see what it does.