Mainz Science Market

Modelling the earth: from computer to lab
09 September 2017/10 September 2017

Linfeng Ding

Beatriz Martínez

Mainzer Wissenschaftsmarkt (the Mainz Science Market) is a major festival for Science in Mainz, which is held once a year to show basic science and research to the general public. People come to the festival to explore the broad spectrum of research in world, establish a dialogue with researchers and have the opportunity to participate in scientific exhibitions and demonstrations. For this reason, this event constitutes a great bridge to connect scientists and local citizens of all ages.

The theme of this year’s Mainz Science Market, “People and Environment”, has been motivated by concerns such as climate change or increasing social injustice, and aimed at making us realize that our actions are decisive for the future development of our planet.

This time, Linfeng and Beatriz, together with the group header Boris, their colleague Xinxin, and the two master students Olga and Jan were responsible for representing the Geophysics group of the Institute of Geosciences at Johannes Gutenberg University in Mainz. For this purpose, we built our exhibition in three blocks: video projection, numerical simulations and basic geophysical experiments.

Attached is the information of our exhibition area on the official Wissenschaftsmarkt webpage:https://www.wissenschaftsallianz-mainz.de/wissenschaftsmarkt/2017/zeltplaeneprogramm/zelt-gruen/modellierung-der-erde-vom-computer-ins-labor/.

For the first block, we prepared a poster summarizing the research projects currently being
conducted by the group, as well as some videos related to the investigation of earthquakes, destruction of volcanic islands, evolution of crustal magmatic systems, subduction zones and lithospheric deformation. We realized, during our stay in the market that one of the main concerns of people was earthquakes, probably due to the recently occurred earthquake in Mexico. Many people asked if it is possible to predict an earthquake and whether it could happen in Mainz. We tried to explain how impossible it is to predict an earthquake even today, but also highlighted the great advances in earthquake mitigation by the construction of safe buildings and the education/ training in dealing with these occurrences.

For the second block, we made available a computer with the tool of visualization ParaView with some 3D-numerical simulations, in order that people could play and analize the data from a setup of the magma chamber of Yellowstone National Park or the subduction collision zone in the Taiwan region.

When we signed up to participate to this science market, we were alerted by the organizers that the public prefers to experiment (to touch, play, ask), and that a large number of children were expected to attend accompanied by parents and grandparents, bursting with curiosity that is not easily extinguished. Therefore, for the third block of our exhibition, taking advantage of our knowledge in analogue modelling acquired in Orsay in the CREEP short course number 4, we took the plunge and organized the experiments section, the higlight of our exhibition. The objective was to let people, especially young children, find out for themselves the basic properties of the materials, their different behaviours when forces are applied on them and to show how the investigation on this subject leads us to better understand our planet.

Therefore we prepared some experiments to explain density, viscosity, cohesion, permeability and porosity, as well as some others to show visco-elasto-plasticity and unexpected behaviours (such as a non-Newtonian fluid).

Among those, the “density” and the “non-Newtonian fluid” experiments attracted the most people. For the density experiment, people could pour in a transparent glass different fluids (e.g., honey, dish soap, colored water or oil) and observe how, surprisingly, the fluids remained unmixed in different layers. Then, they could drop in the glass some solids such as nuts, grapes, foam, marbles or dices, guessing in which of the layers these objects would be trapped. With the beautiful colorful result of the experiment, children had a more intuitive feeling about the concept of “density”. For the non-Newtonian fluid experiment, also quite popular among the older audience, we mixed water and corn starch, and visitors were able to test with their own hands how the mixture behaved as a liquid if manipulated slowly or as a solid if manipulated fast.

In conclusion, we spent this wonderful weekend of exhibition at the Mainz Science Market, ending it exhausted but happy to have had the opportunity to share, from the heart, the small wonders of science with the hundreds of visitors of all the ages, and also for having realized how people trust scientists and how much responsibility our work involves.