Pitch tar drop finally falls!

Here's what's probably the longest running experiment in the world, right here in sunny Ireland! In 1944, physicists at Trinity College Dublin set up an experiment to demonstrate that, firm and stable appearances aside, tar pitch is, in fact, a liquid. The pitch-drop experiment was born. Tar pitch is the material used to coat roofs and pave roads. If you hit it with a hammer, it shatters like a solid. But it’s actually a liquid. It even flows like a liquid. It just does it very, very, very slowly. Finally, after 69 years, the tar pitch dropped! According to Nature, the Trinity College team has estimated the viscosity of the pitch “in the region of 2 million times more viscous than honey, or 20-billion times the viscosity of water.”