Trinity pitch-drop falls for first time in five years

The funnel, dated October 1944, is the second oldest example of this experiment.

On October 24, the pitch-drop experiment saw drop fall for the first time since 2018.

The apparatus was housed in the orientation area between the libraries, however has since been moved to the physics department, to facilitate easier viewing, and to allow continuous filming of the experiment. The experiment aims to demonstrate the extremely high viscosity of pitch, with the frequency of movement occurring every 5-10 years.

Pitch, the material inside the apparatus, is a black polymeric material with an incredibly high viscosity. Pitch is solid when held and will shatter when hit. If left for a long enough period of time under the force of gravity, pitch will flow, like liquid.

The funnel containing the material was discovered in the 1980s, when the School of Physics found the apparatus gathering dust amongst their antique products in the department. The funnel, dated October 1944, is the second oldest example of this experiment.

A similar funnel is located at the University of Queensland, which caught public attention when a drop was produced in November of 2000.

The origin of the experiment is not known, though some presume it to have been created by the physics Nobel laureate and Trinity professor Ernest Walton, famed for splitting the atom.

In 2013, video footage of a drop in the Trinity pitch funnel was uploaded to YouTube, attracting over a million views. The event was listed in Discover magazine as one of the year’s top 100 science stories, and the following drop took place five years later in 2018, though was not caught on camera. 


It must be noted that the pitch-drop lacks many qualities required to define it as a true experiment, with nothing around the funnel controlled. As stated by physicist and University College Dublin (UCD) assistant professor in science education  Dr Shane Bergin: “It’s not an experiment. It was designed as a curiosity, and I guess it’s interesting because it is a curiosity, because for someone who isn’t a scientist, they can be as enthralled by it as someone who is. Scientist or a mathematician.”

The funnel and apparatus of the pitch-drop can now be viewed in the School of Physics.