Measurement of bitumen viscosity in a room-temperature drop experiment: student education, public outreach and modern science in one

Abstract

The slow flow of a viscous liquid is a thought-provoking experiment that challenges students, academics and the public to think about some fundamental questions in modern science. In the Queensland demonstration—the world's longest-running experiment, which has earned the Ig Nobel prize—one drop of pitch takes about ten years to fall, leading to problems for actually observing the drops. Here, we describe our recent demonstration of slowly-flowing bitumen where appreciable flow is observed on the timescale of months. The experiment is free from dissipative heating effects and has the potential to improve the accuracy of measurement. Bitumen viscosity was calculated by undergraduate students during the summer project. Worldwide access to the experiment, as it runs, is provided by webcams uploading the images to a dedicated website, enhancing the student education experience and promotion of science. This demonstration serves as an attractive student education exercise and stimulates the discussion of fundamental concepts and hotly debated ideas in modern physics research: the difference between solids and liquids, the nature of the liquid–glass transition, the emergence of long timescales in a physical process and the conflict between human intuition and physical reality.