After 69 years, 'pitch drop' experiment finally caught on video

In 1927, a researcher at the University of Queensland in Australia began what's widely recognized as the longest-running experiment ever, the so-called "pitch drop." It's a simple set up: fill a flask with tar pitch and let it ooze out the bottom to see how quickly it flows, and eventually it makes a proper drop that falls down -- about once every ten years or so. Tar pitch is a substance that appears to be solid, but in fact is actually a slowly flowing liquid. However, since the beginning of t...