MASS CAFÉ: Picturing Uncertainty within Coffee Ring Effect


Session Title:

  • Technology (Papers)

Presentation Title:

  • MASS CAFÉ: Picturing Uncertainty within Coffee Ring Effect




  • This paper suggests ‘picturing uncertainty’ by utilizing the coffee ring effect and the uncertainty principle in the communicative space. The shape of a coffee bean is handsome like a human brain, which is divided into left and right cerebral hemispheres. In fact, coffee has an arousal effect associated with the human brain. Coffee has released various     research topics in physics. One of them is the coffee ring effect that coffee particles become concentrated along the edge of a stain as the coffee liquid evaporates. It is familiar to anyone who has observed the drying process of coffee liquid. The exhibition project, ‘MASS café’ was held in the space MASS in Seoul, Korea, November 23‑29, 2013. In the project, we installed “Picturing Uncertainty: Coffee Ring Traces” that viewers enjoyed coffee time in the space. It was to archive various coffee rings as a communicative media on the site. Variable coffee rings have been collected for the past half-year under several controlled conditions. We coined conditions by putting the uncertainty principle into the coffee ring effect. The key formula of Heisenberg’s uncertainty principle is:


    It simply says that the location and momentum of a particle cannot be simultaneously measured with high precision. That is, the more certain particles’ momentum is, the more uncertain particles’ location is (or vice‑versa). According to the interpretation, we thought that uncertain locations of particles can be pictured in a small cup. In fact, we were able to get diverse pictures of coffee rings by controlling the speed and spatial variation of the evaporation. The controlled conditions were related to the degree of uncertain momentum (Δp) and resulted in changing the degree of uncertain location (Δx). Here, drying temperature and solution viscosity play an important role as main moderating variables. The high uncertainty of momentum is caused by high temperature as well as low viscosity; higher temperature or lower viscosity allows the particles to move in the more diverse directions. Then it leads to the low uncertainty of location; higher uncertainty of momentum helps the specific particle to be detected in the specific site with higher probability. But to the contrary, low temperature and high viscosity lead to the low uncertainty of momentum and the high uncertainty of location. These processes of the uncertainty principle are eventually connected with the shapes of coffee rings. While the shapes caused by high uncertainty of momentum and low uncertainty of location are various as well as unpredictable, the shapes caused by low uncertainty of momentum and high uncertainty of location are stable as well as analogous to ellipse. The result implies the relationship between particles’ locations and particles’ movements in the microscopic world. Furthermore, in this project, we conceptualize coffee ring traces as pictures of uncertainty, speculating individuals’ locations and movements in the communicative world. It might be possible for us to understand the relationship between individual locations and individual movements in our world