Making plaster cast of footprint

University of Colorado-Boulder Professor Payson Sheets uses dental plaster to cast a footprint found on an elevated road, known as a sacbe (SOCK-bay), that was buried under 16 feet of volcanic ash. The large, white road led in and out of the Maya village of Ceren in El Salvador. In A.D. 660, the ...This is an NSF Multimedia Gallery item.
Source: NSF Multimedia Gallery - Category: Science Source Type: video