Teaching erosion and landscape evolution with an Augmented Reality Sandbox

Augmented-reality sandboxes are increasingly used for outreach purposes in many fields. Here we show the benefits of modifying a standard AR sandbox to significantly improve its teaching capability in Earth Science.

First prototypes of AR sandboxes date back to at least (Microsoft Fest conference in Prague), consisting of a Kinect card scanning the surface of the sand and producing a digital elevation model (DEM) of it in real time. This DEM is used to compute the flow of virtual water on the surface and produce an image combining the DEM and the water, which are projected back on the surface through a standard image projector, also in real time. In this way, water appears to flow on top of the actual sand topography, responding to any manipulation of the surface within a time lag shorter than 1s. The idea was popularized thanks to the open-source ARSandbox distribution published by Reed & Kreylos (2014). 

In our portable sARndbox device, we have modified the original GLSL (OpenGL Scripting Language) SARndbox code with the purpose of teaching experimentally how erosion and geodynamics interact during the development of Earth's topography and relief. Our version of the Fragment Shader file allows to visualize the areas of enhanced erosion and sedimentation driven by high and low water energy, respectively, to better communicate its role in shaping landscape. This is done by colour-shading water as a function of water flow energy, which is approximated as proportional to water depth and velocity at each location. The modified scripts and other info is available on GitHub (https://github.com/danigeos/sARndbox). 

The setting has proved useful in conveying basic principles of landscape evolution to students ranging from primary school to master level. We used this in combination with 3D prints of real tectonic plates and concept explanations, in sessions lasting typically between 30 and 60 minutes.