In the library lobby, students stand transfixed by the sandbox. As they smooth, spread, and pile up sand, an infrared light above them senses their movements and responds to the changing landscape they’re creating.

The tool is Bowdoin’s new augmented sandbox, which mesmerizes as it demonstrates hydrological and geological concepts, such as how water moves through land, both during floods and in droughts.

“One of the aims of this device is to help people visualize topography, watersheds, and catchment areas — what they look like in three dimensions,” explained Paul Benham, an academic technology consultant at Bowdoin.

With help from Bowdoin’s physics machine shop, Benham created the augmented reality sandbox and set it up in the Hawthorne-Longfellow Library (where it will be for the next few weeks). Its permanent home will be in Druckenmiller Hall, where students studying earth and oceanographic science can use it to augment their studies.