During a test run of the DJI Phantom II quadcopter on July 22, 2014, the quad flew away and landed in a field. This video was recorded and shows its 2300-meter-long adventure through the University of York campus and to a nearby school field. Dave Hay, from the Environment Department, put this video on YouTube […]
Obsidian tools
Obsidian is a volcanic extrusive rock with a glassy texture that is very hard and dense. The volcanic glass is usually black in colour, but it can also be dark green and brown. In rare cases trace elements of mineral crystals can cause obsidian to reflect light in various colours, or even the colour spectrum […]