World's Slowest-Moving Tar Pitch Drop Caught on Camera (Video)

Tar pitch is thick and viscous, appearing to be almost solid as it slowly oozes. About 69 years ago, scientists set up a pitch-drop experiment to test exactly how long it would take for a single piece of the black substance to fall into a beaker. Now the experiment is finally over--the researchers have caught the falling drop on camera.

The Dublin pitch-drop experiment was first set up in 1944 at Trinity College Dublin. The researchers wanted to demonstrate the high viscosity of pitch, a material that appears to be solid at room temperature but is, in fact, just moving extremely slowly. Now, researchers have shown exactly how long it takes for a drop of pitch to fall.

Yet this isn't the only pitch-drop experiment. Another one was set up at the University of Queensland in Brisbane. This better-known experiment experienced a drop in 2000. Unfortunately, the camera was off at the time and it wasn't caught on film.

So how was this experiment set up in the first place? The scientists heat a sample of pitch and pour it into a sealed glass funnel. Then, this pitch is given time to settle and consolidate before the sealed stem of the funnel is cut. In the case of the Queensland experiment, this took about three years.

Then comes the waiting. It takes about seven to 13 years for a drop to fully form, but only seconds for it to fall. This means capturing the event on camera can be difficult if the scientists aren't vigilant. In this case, though, they met with success. On July 11, the researchers finally watched as the pitch dripped.

The experiment revealed that pitch is about two million times more viscous than honey, which is 20 billion times the viscosity of water. Although the speed of drip formation depends on the exact composition of the pitch, the new findings reveal a little bit more about the material, according to Nature.

The findings are published in the journal Nature Communications.

Want to see the dripping pitch for yourself? Check out the video below, courtesy of YouTube.