Small brass floor plug is part of big project

brass gravity plug

Field technicians working with the National Geodetic Survey stopped by the Christian Petersen Art Museum in Morrill Hall on July 15 with a heavy-duty drill and a brass plug. Their job was to drill a hole in the floor and glue the plug in place. Next summer, researchers will set a nearly $2 million instrument on the plug to measure absolute gravity at that spot. The mark allows researchers to do any follow-up studies at the same spot.

Franek Hasiuk, assistant professor of geological and atmospheric sciences, says gravity varies depending on your distance from the center of the Earth and the material underground. The field work is part of an update of the National Spatial Reference System, the basis for all federal mapping activities. Here, technician Don Breidenbach shows off the Ames gravity mark. Photo by Mike Krapfl.